Celebrating Our Unsung Pollinator Heroes

The Baltimore oriole (Icterus galbula) is Maryland's state bird and the namesake of its professional baseball team. The Baltimore oriole (and all American orioles) are actually members of the blackbird family, and are related to the tricolored blackbird. For a time, the Baltimore oriole was “lumped” together with the Bullock’s oriole to the west under the name “northern oriole.” The “splitters” have won out again, and the two are recognized as separate species, except in the Western prairies, where they hybridize. In fact, the Baltimore oriole shows more genetic similarities to the Altamira oriole (which lives in Mexico, northern Central America, and a tiny part of Texas), and especially to the black-backed oriole (from Mexico).

Fun fact: The Baltimore orioles’ slender beaks allow them to feed in an unusual way. By first piercing soft fruits with their closed bills, the birds open their mouths to cut a strip through the juicy fruit, allowing them to drink the gushing liquid with their brushy-tipped tongues, in a process called “gaping.”

Range

Baltimore orioles are commonly found during spring and summer months in the eastern and central U.S., and in southern Canada. They will migrate in July to warmer habitats in southern U.S. states and Mexico, as well as in South America, where they will winter in open-forest habitat on shade-grown coffee and cacao plantations. Baltimore orioles avoid the dry season, returning to the Northern hemisphere when food and water in southern climes become scarce. The Audubon Society predicts that climate change will move the oriole’s nesting range further north over the coming century, eventually driving it out of Baltimore.

Physiology

The male has brilliant orange plumage with black and white wings. His tail is also black, with orange, flaring edges. He has a sharp-pointed silver-black bill, and a black head and upper back. The female’s bill is also pointed. Her colors, however, are somewhat subdued —her head and back are gray-olive, her breast and tail a lighter yellow-orange, and her wings gray-brown with white accents. Both males and females are medium-sized and have three toes pointing forward and one pointing back, a branch grip that enables the birds to perch. Both male and female sing — a song the Cornell Lab of Ornithology describes as “flute-like,” and “[consisting] of a short series of paired notes, repeated 2–7 times, lasting 1–2 seconds.”

Baltimore orioles are known for their distinctive hanging, pouch-shaped nests, typically anchored in drooping branches of tall shade trees such as the American Elm. Females take one week to build their nests out of flexible materials ranging from Spanish moss and twigs to fishing line and horsehair. Adults lay one clutch of 3–7 eggs per season. In summer, after breeding and before migrating, Baltimore orioles will molt their plumage. The diet of Baltimore oriole adults, while breeding and feeding their young, consists mostly of nutrient-rich insects, but they also consume sugar-rich fruits to store energy prior to and during their long migration.

Ecological Role and Threats to Existence

During the breeding season, Baltimore orioles eat a wide variety of insects, including many so-called “pest” species, such as larvae within plant galls, tent caterpillars, gypsy moth caterpillars, fall webworms, and spiny elm caterpillars, that many other bird species avoid. By foraging through the treetops, leaves, and branches, and feeding on large quantities of larvae and insects, the Baltimore oriole protects trees from suffering extensive damage.

During northern winter months, Baltimore orioles feed on fruit trees and vines in the Neotropics. While enjoying the fruit, many birds may ingest and excrete whole seeds, a symbiosis that feeds the bird while aiding the dispersal of the seeds through the oriole’s flight.

In visiting flowering trees and vines in search of nectar, Baltimore orioles become much-needed pollinators. In the process of reaching for nectar, having a comparatively shorter beak than the hummingbird’s, a Baltimore oriole’s body becomes covered with pollen, dusting the forehead, chin, bill, and feathery breast. As birds move from plant to plant, they carry pollen to nearby and adjoining flowers, pollinating plants wherever they feed.

A Baltimore oriole’s preferred plants have tight clusters of fruit and flowers, as well as sturdy supporting branches to enable a secure perch while feeding. Like the liana Combretum fruticosum of Mexico and South America, plants that attract Baltimore orioles and other strictly perching, or “passerine,” birds, produce very hexose-dominant (low in sucrose) nectars, which makes them poor hummingbird food.

Habitat loss at breeding and wintering grounds, pesticide use on neighboring farm fields and gardens, and collisions with glass are the principal threats to this species. In addition, in the mid-twentieth century, Dutch elm disease infected and killed a majority of American elm trees — favorite nesting trees for Baltimore orioles because of their spreading form and drooping branches.

How to Protect the Species

To deter collisions with frenzied flyers, put startling images or light-reflecting stickers on windows to make the surface more visible. See the American Bird Conservancy’s suggestions.

Protect existing wild spaces and large shade trees. As Baltimore orioles breed in open forest edges and riparian areas, on farms, and in fruit orchards, plant trees and native hedgerows along rivers and lakes. Water saplings regularly, apply mulch before harsher winter months, and monitor the health of maturing trees in your community.

Avoid using pesticides! Many toxic chemicals applied on lawns, farms, and sports fields are toxic not only to birds, but also, to insects. Pesticide spray can similarly poison Baltimore orioles’ much-loved fruit trees.

Backyard feeders are a great way to attract and sustain Baltimore orioles under stress, or during their preparation for southern migration to over-winter. Given orioles’ fondness for fruit and nectar, as well as insects, those interested in creating Baltimore oriole feeders in their backyard or school playground can incorporate orange slices, or even jam as a sugary nectar alternative. Baltimore orioles are especially attracted to dark-colored mulberries, cherries, and grapes.

Contact the American Bird Conservancy for further information.

Citations:

American Bird Conservancy, Baltimore Oriole: https://abcbirds.org/bird/baltimore-oriole/

The Cornell Lab of Ornithology:https://www.allaboutbirds.org/guide/Baltimore_Oriole/overview

Avian Pollination: ftp://169.158.189.34/pub/Biotropica/1990s/1990/22-3/Biotropica-1990-22-3-p266.pdf

All About Birds, Baltimore Oriole: https://www.allaboutbirds.org/guide/Baltimore_Oriole/lifehistory

 All About Birds, Baltimore Oriole, Bullock’s Oriole: https://www.allaboutbirds.org/guide/spp_photos.aspx?spp=3&sppid=36&keepThis=true&TB_iframe=true&height=488&width=875

Journey North, Oriole, “From Northern Oriole to Baltimore and Bullock's 
A Split Decision”: https://journeynorth.org/tm/oriole/Baltimore-BullocksSplit_Rising.html

Audubon Guide to North American Birds, Baltimore Oriole: http://www.audubon.org/field-guide/bird/baltimore-oriole

 

Beetles in the family Cantharidae are known as soldier beetles, a name that is based on the resemblance of the elytra (wing covers) to certain military uniforms. These beetles superficially resemble fireflies (family Lampyridae), but lack light-emitting organs and the covering obscuring the head of fireflies. Like fireflies, soldier beetles are distasteful to most predators.

Range

There are 16 genera, containing 455 species, of soldier beetle native to North America, including Chauliognathus marginatus, which is commonly seen on goldenrod in late summer and early fall. Worldwide, there are approximately 5,100 species across 160 genera, widely distributed in all but the polar regions. Most frequently active in summer and early fall, adults can be found on various flowers, including sunflower, tansy, zinnia, marigold, goldenrod, and coneflower. Females lay eggs in clusters in the soil. They live through the winter under loose soil, and become active during spring. Larvae normally pupate in early summer and adults first emerge in mid-summer.

Physiology

The soldier beetle’s body is ½ to ¾ inch long. Adults are black or brown, usually with red to yellow markings, an “aposematic” signal to predators, warning of an unpleasant taste. The elytra are soft wing covers, hence the nickname “leatherwings.”

Adults and mature larvae have chewing mouthparts. After hatching, the larvae are tiny and white, but 24 hours after their first molt, they begin to move and darken. To quote University of Minnesota Extension Entomologist Jeff Hahn, the dark larvae come to “resemble miniature alligators.”

Soldier beetle adults and larvae, when attacked, can emit a spray of dihydromatricaria acid from glands along their bodies, causing the majority to be either avoided or outright rejected by potential predators, such as birds, mice, and jumping spiders.

Ecological Role and Threats to Existence

After soldier beetles hatch in the summer, larval activity increases with each successive molt. Soldier beetle larvae are largely carnivorous, foraging for soil insects, aphid eggs, worms, slugs, and snails among assorted plant debris. As they feed, soldier beetle larvae reduce the number of eggs and larvae of other soft-bodied insects, such as aphids, thereby limiting the ability of those insects to damage crops.

Soldier beetle adults feed on the pollen and nectar of flowers, as well as other insects, pollinating the flowers as they move about. Beetle-pollinated flowers are generally open and fragrant, allowing beetles to pollinate the flowers as they scramble across them. The same flowers serve as mating sites for the soldier beetles.

Although harmless to humans, the soldier beetle is among a long litany of “non-target” species that may be poisoned, or whose source of both food and habitat may be poisoned, by the use of pesticides.

How to Protect the Species

Swaths of wildflowers, native shrubs and trees, and urban green spaces provide good habitat for adult soldier beetles and other pollinators. Similarly, because the beetles deposit eggs into soil, or loose leaf litter, it is critical to eliminate the use of synthetic fertilizers and toxic pesticides that threaten soil life. Adopting organic land management practices, such as planting pollinator habitat conservation strips and cover crops, using mulch for weed control, and adding compost to gardens, lawns, and farm fields, helps to build and protect biodiversity. The resulting rise of soil organic matter provides healthy hunting grounds for voracious soldier beetle larvae.

Citations:

University of Minnesota Extension: https://extension.umn.edu/yard-and-garden-insects/soldier-beetles

University of Kentucky Entomology: http://www.uky.edu/Ag/CritterFiles/casefile/insects/beetles/soldier/soldier.htm

Virginia Cooperative Extension: https://vtechworks.lib.vt.edu/bitstream/handle/10919/51406/ENTO-53.pdf?sequence=1&isAllowed=y

Encyclopedia Britannica: https://www.britannica.com/animal/soldier-beetle

United States Department of Agriculture, Forest Service: https://www.fs.fed.us/wildflowers/pollinators/animals/beetles.shtml

Bug Guide. Family Cantharidae, Soldier Beetles. http://bugguide.net/node/view/118

Cirrus Images. Soldier Beetles, Family Cantharidae. http://www.cirrusimage.com/beetles_soldier.htm

Jesse, Laura. Iowa State University Extension and Outreach, Horticulture and Home Pest News, July 1, 2009. Soldier Beetles Common on Blossoms Now. https://hortnews.extension.iastate.edu/2009/7-1/soldierbeetle.html

Pleasant, Barbara. Mother Earth News, Feb. 6, 2013. Soldier Beetle Facts: Attract This Bustling Beneficial. https://www.motherearthnews.com/organic-gardening/pest-control/soldier-beetle-facts-zw0z1302zkin

White, R.E., 1983. A Field Guide to the Beetles of North America. Peterson Field Guide Series, Houghton-Mifflin, Boston, MA.

The bog copper butterfly (Lycaena epixante) is a member of the second largest family of butterflies, Lycaenidae, which includes more than 4,700 species worldwide. Also known as the cranberry-bog copper butterfly, the species has strong biological ties to the cranberry plant and its associated habitat.

Range

Bog coppers are unevenly distributed throughout Northeast United States and into Canada, with some ranging as far west as Minnesota. Populations are generally concentrated in acidic bog environments containing wild cranberry, but have also been sighted in other damp acidic habitats, such as wet meadows. The butterfly requires an environment that is wet year-round, with ample sunlight. Bog coppers are highly adapted to this environment and do not migrate.

Diet and Pollination

The life cycle of the bog copper strongly depends on cranberry plants. Female butterflies lay single eggs on leaves in late summer or early fall, on the underside of a cranberry, usually near the edge of the bog, where the cranberries live among taller sedges. Each female may lay 20–40 eggs. After developing into a first-stage larva within the egg, the larva is protected from ice and freezing temperatures during the winter by entering a state of diapause, or dormancy. The egg is protected from desiccation by the moist environment under the leaf, and from flooding by a convoluted membrane that traps bubbles of air. Bog coppers spend roughly 85% of their lives in their egg stage, emerging as larvae in spring to feed on cranberry leaves where the egg was laid. After a brief pupation period, bog coppers emerge as adults, and mating occurs 2–3 days before the females lay eggs. Cranberry-bog copper adults feed almost solely on cranberry nectar, and their life cycle is timed so that emergence of adults coincides with the flowering of cranberry plants. It may come as no surprise that the species is an important pollinator of wild cranberries.

Physiology

The bog copper is the smallest of the copper butterflies found in the U.S., with a wing span ranging from 3/4” to just under an inch. The wings of both males and females are dark grey to brown on the front side, with a tinge of purplish gloss. Males also have black dots and an orange zig-zag line at the base of the front side of their wings. Both sexes have a white border around the wing edges. The back side of both males and females is generally gray to tan with small black spots and a reddish zig-zag at the base.

Ecological Role and Threats to Existence

Bog coppers are important pollinators of both large and small cranberry plants but not an important part of commercial cranberry production because the butterfly is highly sensitive to insecticide exposure. Thus, bog coppers are rarely found in commercial cranberry farms, leaving pollinators like the honeybee to perform the necessary pollination.

Recent research from Ellwood, et al. finds that as a result of climate change, bog coppers and cranberry plants are increasingly mismatched ecologically. Cranberry plants flower earlier in warmer years. This is leading to unhappy consequences for bog coppers, which have not been known to alter their behavior in response to temperature changes. Thus, if cranberries flower earlier than bog coppers emerge as adults, the butterflies are likely to miss out on their critical food source. For any bog coppers who may incidentally be on a nonorganic cranberry farm, early flowering may mean that the bog copper emerges at a time when insecticide spraying is most active.

Cranberry-bog coppers are at risk from habitat destruction, as well as from insecticide use. Acidic areas where the insects live are prime spots for the development of peat mining or the creation of industrial cranberry operations. Natural hazards have always posed a threat — beavers, ecosystem engineers that they are, can both create and destroy the conditions that bog coppers need to thrive. This small pollinator is also at risk from fire, natural succession to forests, and severe floods.

How to Protect the Species

Encourage a safer environment for cranberry-bog coppers by purchasing organic cranberries and cranberry products. Conventional cranberry production is known to make use of neonicotinoid insecticides, which, once applied, will make their way into a plant’s vascular system and express themselves in its pollen and nectar. Given that the bog copper’s entire life cycle depends on consuming the cranberry plant, it is little wonder that so few are found in and around commercial cranberry bogs. In addition to insecticides, conventional cranberry production applies significant quantities of fungicides, such as chlorothalonil and azoxystrobin, which are also likely to affect non-target pollinator species such as bog coppers. Buying organic cranberry products will encourage the industry to transition to practices that do not necessitate the use of these toxic chemicals, and are likely to make commercial cranberry production a safer environment for the bog copper.

Although bog copper populations are considered relatively stable, their long-term outlook is questionable. Though many states and localities protect native cranberry bogs, pressures from climate change and development will remain a factor for many years to come. Protecting these species will require concerted efforts to preserve their native habitat, and eliminate the introduction of environmental stressors such as pesticides. 

Citations

Averill, A. and Sylvia, M., 1998. Cranberry Insects of the Northeast, University of Massachusetts Amherst. http://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1023&context=cranberry_factsheets

Ellwood, et al., 2013. Cranberry flowering times and climate change in southern Massachusetts. International Journal of Biometeorology. DOI 10.1007/s00484-013-0719-y https://www.researchgate.net/publication/256480641_Cranberry_flowering_times_and_climate_change_ in_southern_Massachusetts

Encyclopedia of Life, N.D. Bog Copper. http://eol.org/pages/2682626/details#cite_note-rcgt-2

Butterflies and Moths of North America, N.D. Bog Copper. https://www.butterfliesandmoths.org/species/Lycaena-epixanthe

Pennsylvania Natural Heritage Program, N.D. Bog Copper. http://www.naturalheritage.state.pa.us/factsheets/11718.pdf

Pelikan, Matt. MVtimes, 2014. A highly evolved butterfly. http://www.mvtimes.com/2014/07/02/highly-evolved-butterfly/

Severns, P.M., Boldt, L., and Villegas, S., 2006. Conserving a wetland butterfly: quantifying early lifestage survival through seasonal flooding, adult nectar, and habitat preference. Journal of Insect Conservation, 10(4), pp.361–370.

United States Department of Agriculture, Forest Service, N.D. The Bog Copper. https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/bog_copper.shtml

Wright, D.M., 1983. Life history and morphology of the immature stages of the bog copper butterfly, Lycaena epixanthe (Bsd. & Le C.) (Lepidoptera: Lycaenidae). Journal of Research on the Lepidoptera.

Pollen wasps, of the small subfamily Masarinae, are the only “vegetarian” wasp in the family Vespidae. They feed solely on nectar and pollen, unlike their more aggressive Vespid wasp cousins. There are 300 species of pollen wasp from 14 genera spread across the globe; however, in the United States, all 14 species of pollen wasps originate from the genus Pseudomasaris.

Range

Pollen wasps are found throughout the world, though they tend to concentrate in arid areas of southern Africa, and North and South America. They are not documented in the tropics or in Antarctica. In the U.S., they can be found from Washington State to as far south as New Mexico, and as far east as Nebraska. They are solitary pollinators who make their nests out of mud, often attached to branches or rocks, or hanging off ledges. 

Diet and Pollination

Pollen wasps differ from their omnivorous Vespid wasp relatives by rearing their young on nectar and pollen, rather than other insects. They are the only Vespid species that do so. Their nests, an amalgam of soil and nectar, usually comprise 4–10 parallel cells that hold an egg, nectar, and a small pollen patty. Pollen wasps then seal their nests with mud. Before emerging, newborn larvae consume the stored food, pupate, and then break through the mud seal as adults.

Pollen wasps are known to specialize in foraging on very specific flowers, including beardtongues, borage, and tansies, though there are also reports of their feeding on mallows and marigolds. These wasp pollinators have long proboscises that allow them to reach nectar in their preferred flowers species. Most bees will use the corbicula, or “pollen basket,” a small indent on their back legs, surrounded by hairs, to secure collected pollen before bringing it back to a nest or hive. However, pollen wasps do not have corbiculae; instead, they collect pollen in their crops. The crop is an expanded portion of the pollen wasp’s digestive track that can be used to store pollen and nectar temporarily, and subsequently, used to feed its young.

Physiology

Pollen wasps are generally striped with colors that may include red, brown, black, white, and yellow. Pseudomasaris species in the U.S. are often mistaken for yellow jackets, as they both share the same striped yellow and black pattern across the tops of their abdomens. The major distinguishing characteristic between the two wasps is the shape of their antennae: yellow jacket antennae stick straight out, whereas pollen wasp antennae are “clubbed” at the end. In contrast to the mud nests of the pollen wasp, a yellow jacket nest is made of paper and grows to thousands of cells by late summer.

There is no reported explanation in current scientific literature for the similarity in appearance between pollen wasps and yellow jackets. However, it may be a form of Batesian mimicry, whereby the relatively docile pollen wasp may evoke avoidance in potential predators because the pollen wasp may be perceived as the more-aggressive yellow jacket. Though pollen wasps rarely sting, they are capable of doing so. Unlike honeybees and like their closer wasp relatives, their stingers are not barbed, allowing the insects to sting multiple times.

Ecological Role and Threats to Existence

Pollen wasps can play an important role in pollinating certain flowers. For instance, the United States Forest Service (USFS) notes that the pollen wasp species Pseudomasaris vespoides specializes in pollinating beardtongue. It has been observed pollinating the blowout beardtongue, an endangered flowering plant limited in range to nine counties in Nebraska and one location in Wyoming. A number of additional rare beardtongue species rely on P. vespoides pollination, giving the insect an important role in maintaining ecological diversity in the Western U.S.

As the National Research Council (NRC) noted in its 2007 report on the status of pollinators in North America, data on the prevalence and distribution ofPseudomasaris species are sparse. For example, P. micheneri has been observed only in the Inyo Mountains of California, and that research was conducted as far back as the 1940s. Another species, P. macswaini, is suspected of having a very limited distribution in California and may be at risk, according to NRC.

How to Protect the Species

One of the most important actions one can take to protect pollen wasps is eliminating the use of pesticides that can harm these unique insects. Neonicotinoids, once applied, will make their way into a plant’s vascular system, and express themselves in pollen and nectar, putting pollen wasps at risk. Other insecticides, like synthetic pyrethroids, are acutely toxic to many non-target pollinators, and may, once applied, leave harmful residue on plants and their flowers. Given the relative paucity of data on the range and distribution of pollen wasps, encouraging public land managers to forgo the use of insecticides and herbicides in natural areas can have an important impact on the availability and quality of forage for pollen wasps.

Although there is insufficient data on pollen wasp flower preferences, and one cannot, for instance, guarantee that the strain of beardtongue planted will be attractive to pollen wasps, establishing a diversity of flowers in one’s garden will foster a diversity of pollinators. In addition to beardtongues, residents within pollen wasp range can try to attract these insects by planting waterleaf species, such as borage and tansies. Last, use careful judgment before swatting at lone yellow jackets, or going after their nests, as they may easily be mistaken for pollen wasps.

Citations

BugGuide, 2005. Subfamily Masarinae — Pollen Wasps. http://bugguide.net/node/view/22272

Eaton, Eric, 2011. Wasp Wednesday: Pollen Wasp. http://bugeric.blogspot.com/2011/11/wasp-wednesday-pollen-wasp.html

Encyclopedia of Life, N.D. Pollen Wasps. http://eol.org/pages/5243/details

National Research Council, 2007. Status of Pollinators in North America. https://www.nap.edu/catalog/11761/status-of-pollinators-in-north-america

United States Forest Service, N.D. Pollen Wasps. https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/masarines.shtml 

Xerces Society, 2011. Attracting Native Pollinators.https://books.google.com/books?id=iTwPEDL3nvMC&printsec=frontcover#v=onepage&q&f=false

Hoverflies, also known as flower flies and syrphid flies, are members of the “true fly” order Diptera, family Syrphidae. There are roughly 200 genera and 6,000 species of hoverflies throughout the world.

Range

Hoverflies are commonly seen in in flowering landscapes across the globe. According to the United States Forest Service (USFS), there are almost 900 species of the family in North America. They live in a range of habitats, including decaying wood, still and moving freshwater, on plants, and sometimes even in other insects’ nests. They are not often found in desert regions, and no known species have been discovered in Antarctica. 

Diet and Pollination

The diet of hoverflies varies widely among species. In general, they are vital pollinators for a range of common flowering plants. Most adult flower flies have generalized mouthparts structured to sap up nectar and harvest pollen from open flowers; others use a long, beak-like proboscis to imbibe nectar from tube-shaped flowers; and some reportedly feed on the honeydew secreted from aphids. Because certain syrphid flies will feed on human perspiration, they are often mistaken for sweat bees. Unlike sweat bees, however, flower flies cannot sting. 

In addition to being crucial wild pollinators, larvae of many flower flies, such as the common Allograpta obliqua, are voracious predators of garden and agricultural pests — particularly aphids. Approximately 40% of larval stage hoverfly species prey on soft-bodied pests. Larvae of these species use their piercing mouthparts to suck aphids dry. The larvae of other hoverflies are not predatory, but instead, feed on fungi or plant material. Some syrphid flies lay their eggs in the nests of ants or bees. Hoverfly larvae inhabiting ant nests consume eggs and larvae of the ants. On the other hand, Volucella species larvae eat dead bees and other organic matter in bumblebee nests.

Physiology

Flower flies provide an excellent example of Batesian mimicry. Although hoverflies do not have stingers, a majority of North American species are black and yellow, resembling some bees or wasps, thus mimicking the warning signals of more dangerous insects. In addition to deterring predators, this camouflage permits certain flower fly species to lay their eggs in other creatures’ nests.

Hoverflies and other Diptera species can be distinguished from bees and wasps by the number of their wings. Flies have one pair of wings, while bees have two. As their name implies, their wings are used to hover over flowers, providing hoverflies an ability to change direction and location quickly. They are among the small number of insects who can fly backwards.

Syrphid fly larvae are much less charismatic than adults: they grow out of dull-colored, oval-shaped eggs, and are born legless and blind. Hoverflies undergo complete metamorphosis, meaning that they will pupate for one to four weeks before emerging in their adult form. 

Ecological Role

Syrphid flies are important pollinators, and many are critical to the cross-pollination of certain plant species. Accounts of pollinators in Colorado’s prairie found that 44% of flowering plants species investigated were pollinated by 16 hoverfly species. While a few species specialize in pollinating certain flowers, most flower flies are generalist pollinators, though they do show a notable preference for white and yellow flowers. Certain hoverfly species are laboratory reared and placed in greenhouses for pepper pollination, or for the production of seeds for seed banks.

Flower fly larvae play an ecological role in pest control and nutrient cycling. Of those that feed on aphids, high larval populations can reduce aphid numbers by 70 to 100%, according to the University of Florida. The larvae of some hoverfly species have been shown to consume an average of more than 30 aphids per day. Although ladybugs and lacewing larvae are more recognizable pest predators in gardens and crop fields, the unassuming larvae of the flower fly may deserve a good share of the credit. For instance, preliminary research finds syrphid flies able to maintain adequate control of aphids in California lettuce crops. Flower fly larvae will also feed on mealybugs, scales, and caterpillars. Syrphid larvae who live in other habitats often assist in the decomposition of organic wastes.

Threats to Existence

Research conducted in Europe finds that hoverfly diversity differs significantly between areas of high and low human activity. Flower fly populations in natural, undisturbed areas are more diverse, with a higher number of species specializing in the pollination of specific flower species. In areas with high levels of human activity, researchers discovered that more generalist hoverflies tend to dominate the landscape. USFS notes that, although no syrphid flies are currently listed under the Endangered Species Act, this may be a result of a dearth of information about these pollinators.

The University of Washington indicates that flower flies are “highly susceptible” to insecticides, and recommends pest managers forgo insecticidal control of aphids if hoverfly larvae have been spotted feeding on them. There is also evidence that pesticide use may deter flower flies from moving into an area in the first place. A 2013 study indicates that syrphid flies may avoid feeding in areas where field-realistic levels of bee-toxic neonicotinoid class insecticides are present.

How to Protect the Species

People can protect hoverflies through some simple actions. Planting a diversity of flowers in and around one’s garden and yard is a surefire way to promote flower fly populations. Flowers in the carrot family, such as dill, Queen Anne’s Lace, fennel, and parsnip are favorites of many species. Hoverflies will also frequent daisies, asters, borage, and buckthorn, as well as perennials such as goldenrod. Try to cultivate a variety of flowers that bloom throughout the year to ensure that forage is always available.

Avoid the use of pesticides that can harm these valuable insects. Neonicotinoids, once applied, will make their way into a plant’s vascular system, and express themselves in pollen and nectar, putting flower flies at risk. Other insecticides, like synthetic pyrethroids, are acutely toxic to many non-target pollinators, and may leave harmful residue on plants and their flowers once applied. Avoid herbicide use as well, which can destroy important habitat and nesting grounds for flower flies. Fostering biodiversity in your yard and garden will ensure a strong population of syrphid flies and other natural predators that will eliminate the need for insecticide use in the first place. 

Citations

BugGuide, N.D. Syrphidae. http://bugguide.net/index.php?q=search&keys=syrphidae

Encyclopedia of Life, N.D. Syrphidae: Flower Flies and Syrphid Flies. http://eol.org/pages/9017/details

Brenner, Kelly, 2015. The Metropolitan Field Guide. Urban Species Profile: Hover Flies.http://www.metrofieldguide.com/urban-species-profile-hover-flies/

Lavoipierre Frederique. Pacific Horticulture, 2017. Garden Allies: Hover Flies.https://www.pacifichorticulture.org/articles/hover-flies/

Ssymank, et al, 2008. Biodiversity. Pollinating Flies (Diptera): A major contribution to plant diversity and agricultural production. Vol 9 (1 & 2). https://repository.si.edu/bitstream/handle/10088/9619/FCT_115.pdf 

University of Illinois Extension, 2014. In the Backyard: Sweat Bees and Syrphid Flies. https://extension.illinois.edu/blogs/flowers-fruits-and-frass/2017-07-20-hover-flies 

University of Florida, 2014. Featured Creatures. http://entnemdept.ufl.edu/creatures/beneficial/hover_fly.htm

Shepherd, Matthew, and Scott Hoffman Black, N.D. USDA/Forest Service. Flower Flies. https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/flower_flies.shtml

Warner, Geraldine, 1993. Washington State University. Syrphid flies (hover flies, flower flies). http://treefruit.wsu.edu/crop-protection/opm/syrphid-flies-hover-flies-flower-flies/

Wikipedia. List of Syrphidae Genera. https://en.wikipedia.org/wiki/List_of_Syrphidae_genera [for a hint of the diversity of the family] 

Hawk moth is the common name for Sphingidae, a family of over 1,400 moth species. They are also commonly referred to as sphinx moths. This family is divided into two subfamilies, five tribes, and 205 genera. The voracious tomato hornworms and tobacco hornworms are larvae of two hawk moth species.

Range

According to a study by the University of Nebraska, hawk moths can be found in all parts of the world except Greenland. Some areas only host these moths for part of the year because many species make seasonal migrations to find reliable food sources and to breed. The study notes that some hawk moth species can even be found in Antarctica and the North Pole.

Diet and Pollination

The hawk moth drinks nectar from sweet-smelling flowers, many of which bloom at night. Most hawk moth species have a long proboscis. This hollow, tongue-like appendage is used to access nectar deep inside flowers. The family has the longest tongues in the moth and butterfly order. In some species, the proboscis reaches over a foot in length. These impressive tongues allow the moths to feed on and pollinate the deepest flowers.

The adults contribute to pollination in a manner similar to many other pollinators. Pollen sticks to the moth’s face, proboscis, and legs when it feeds. It then transports the pollen to successive flowers. A 1995 study at University of Massachusetts, Boston on the speed of hawk moths noted that the family uses a hovering method, similar to that of hummingbirds, while feeding on flower nectar. Additionally, tobacco, tomato, and other nightshade species play host and food source to the hawk moth larvae.

Physiology

The USDA Forest Service notes that some of the largest moths in the world belong to the sphingidae family. Moth size varies by species, but the largest can have wingspans over ten centimeters. Hawk moths are fast and powerful flyers. The University of Massachusetts, Boston study found one species capable of flying at a speed over twelve miles per hour.  They have four long and narrow wings that they use to travel great distances in search of food and in annual migration. The University of Nebraska study reported that off-shore studies have been conducted that attracted moths for study with ship lights as many as sixty miles from land.

The many hawk moth species vary in color and pattern. Their bodies are covered in narrow scales, similar to a mammal fur, which act as insulation to maintain a high temperature. They have been observed “shivering” in a similar manner to mammals in low temperatures.

Science Magazine reports that the hawk moth is among a number of insects that use their antennae as gyroscopes to maintain stability in flight. The antennae allow the moth to sense rotations, which are adjusted for by the four wings.

Ecological Role

The hawk moth plays an important role as both a pollinator and prey. As previously mentioned, the hawk moth pollinates as it feeds on flower nectar. Moth pollination is important for night-blooming plants, which are not readily serviced by daylight pollinators like bees. Additionally, the University of Nebraska study notes that hawk moths and their larvae are prey to birds, bats, small mammals, and even other insects. Their vulnerability to predation has resulted in the evolution of protective mimicry –as in the appearance of the bumblebee hawk moth and the inflatable snake head on the tail of Hemeroplanes triptolemus larvae.

Threats to Existence

The hawk moth, as a large family of moths, is not endangered. Its broad speciation and range indicate the family’s adaptation to different conditions. However, the International Union for Conservation of Nature’s Redlist lists threats to a couple of hawk moth species. The Prairie Sphinx Moth, native to the United States, has been considered critically endangered since 1996. It faces an extremely high risk of extinction in the immediate future. The Fabulous Green Sphinx Moth of Kauai was considered extinct between 1986 and 2002. However, the moth was observed in limited numbers and noted as “data deficient” in 2002 before being reclassified as endangered in 2004. It faces a high very high risk of extinction. The most up-to-date assessments identify as threats to this species and the diversity of plants and insects on the island a number of factors, including agricultural development and the plants and animals it brings to the island. Further disturbance, such as hurricanes, exacerbates the problem. The 2015 study Effects of neonicotinoids and fipronil on non-target invertebrates names moths among other beneficial insects as likely to experience “wide ranging negative biological and ecological impacts.”

How to Protect the Species

The steps you take to protect the hawk moth depend on which species live in your area. Use the Butterflies and Moths of North America Checklist to determine which species of moth are common in your area. The website will also provide you with the information you need to help protect pollinating moths, including their migratory schedule, preferred habitat, caterpillar host plants, and adult food plants. Once you’ve found that information, you can make sure your garden includes flowering plants that are available for nocturnal pollinators.

You can also support the hawk moth family by providing a range of flowers they prefer in your garden. They are particularly fond of petunias, trumpet vine, jimpsonweed, and Queen of the night cactus. These flowers all exhibit strong, sweet fragrance, long floral tubes, and large volumes of nectar. More generally, you can plant white and yellow night-blooming flowers in addition to those previously mentioned.

In addition to providing food and habitat for your local hawk moth species, take measures to ensure your garden is not contaminated with pesticides. Neonicotinoids are a particularly harmful class of pesticides that enter plants, contaminate nectar and pollen, have been documented to decimate non-target insect populations. Avoid introducing plants that have been treated with pesticides, especially neonicotinoids. Read more about the effects of neonicotinoids on our page Chemicals Implicated.

Citations

Buchman, Steve Hawk Moths or Sphinx Moths (Sphingidae) https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/hawk_moths.shtml

IUCN Red List Euproserpinus wiesti http://www.iucnredlist.org/details/8373/0

IUCN Red List Tinostoma smaragditis http://www.iucnredlist.org/details/21913/0

Messenger, Charlie The Sphinx Moths (Lepidoptera: Sphingidae) of Nebraska http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1071&context=tnas

Sane, Sanjay P. Antennal Mechanosensors Mediate Flight Control in Moths http://science.sciencemag.org/content/315/5813/863

Stevenson, R.D. Cage Size and Flight Speed of the Tobacco Hawkmoth Manduca Sexta http://jeb.biologists.org/content/jexbio/198/8/1665.full.pdf

Pisa, L.W. Effects of neonicotinoids and fipronil on non-target invertebrates https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4284392/

Name

The Mexican long tongued bat, scientific name Choeronycteris mexicana, is a species of bat aptly named for its tongue, which has the remarkable ability to extend to nearly a body length. It is less-commonly referred to as the hog-nosed bat.

Range

The Mexican long-tongued bat’s range extends from the southwest of the United States through Mexico and into Central America, according to the International Union for Conservation of Nature (IUCN). In the United States, the bat is restricted to the far-south of California, Arizona, Nevada, New Mexico, and Texas. It is found in most areas of Mexico but is absent from the Yucatan peninsula and the gulf coast. Further south, the bat is also found in southern Guatemala and El Salvador in addition to northern Nicaragua. The Mexican long-tongued bat participates in seasonal migrations rather than hibernation. The Texas Parks and Wildlife Department admits that the study of the bat’s migratory patterns has been inadequate. However, it is known that the females establish maternity roosts in the southwest of the United States in late spring. They and their young depart for Mexico and Central America with the onset of cold weather in October and November. There is some evidence that a few individuals will remain in warmer northern areas over the winter.

Diet and Pollination

Mexican long-tongued bats feed primarily on the nectar and pollen of night-blooming flowers. Favorites include agave and cacti. They are also known to eat cactus fruit as well as insects found on flowers and fruit where they feed. Their preferences for agave and cactus makes them an important pollinator as they carry pollen from one plant to another. The United States Department of Agriculture Forest Service notes that bats primarily pollinate large flowers that produce strong fragrance and large volumes of nectar. Over three-hundred species of fruit-bearing plants depend on the Mexican long-tongued bat and other bat species for pollination.

Physiology

The Mexican long-tongued bat belongs to the group of phyllostomid or “leaf nosed” bats. These bats are characterized by a projection from the end of the nose that looks like a leaf. The Texas Parks and Wildlife Department advises that the Mexican long-tongued bat can be distinguished from other “leaf nosed” bats by their short ears, narrow snout, and presence of a small tail. The Smithsonia Museum of Natural History notes that the nose leaf may help direct the bat’s echolocation signals. The National Science Research Library at Texas Tech University describes the Mexican long-tongued bat as medium sized – between three and four inches in length and weighing less than a tenth of a pound – with sooty-gray to brown coloration. Their extendable, long, tapering, brush-tipped tongues allow them to access nectar from deep within a great variety of night-blooming flowers while hovering.

Ecological Role

The Mexican long-tongued bat plays a multifaceted ecological role as predator, prey, and pollinator. Their diet largely consists of agave nectar and they play a major role in the pollination of non-cultivated agave. While nectar and pollen are their primary food source, they also prey on any insects who are present when they are feeding at a flower. In addition to their role in pollination, the bats also contribute to the survival of cacti by dispersing their seeds. According to the food-web site, What Eats, bats play an ecological role as part of the diet of a number of predators. Predatory birds, like hawks and owls, in addition to snakes and predatory mammals are known to include bats among their prey.

The role of the Mexican long-tongued bat in pollination has been somewhat diminished by the expansion of agriculture in its range. According to a 2014 Wired article, cultivated agave is actively pruned to prevent flowering. These agave reproduce via proliferation of plantlets. The Mexican-long tongued bat and other bat species mentioned in the article do not play a primary role in producing commercial agave “nectar,” which is not floral nectar, but a synthetic syrup made from the sap of the agave plant. In fact, destruction of habitat to create commercial agave fields may actually be hurting the bat populations.

Threats to Existence

The International Union for Conservation of Nature’s Red List categorizes the Mexican long-tongued bat status as “near threatened.” This means that the species is not currently endangered or vulnerable but is close to qualifying for those designations and is expected to move to a threatened category in the near future. The IUCN cites its wide range across North and Central America as an encouraging point but also cites concerns regarding the species dependence on fragile agave populations which are subject to infringement by livestock grazing and the practice of prescribed fires.

In addition to danger relating to the availability of agave, the Mexican long-tongued bat is subject to the threat of loss of roosting sites. The caves which harbor these bats are increasingly being invaded by miners and caving tourists which render the caves inhospitable. The Texas Parks and Wildlife Department clarifies that the bats are very sensitive and, when disturbed, will abandon their roost.

A recent study in Taiwan connected the use of imidacloprid, a neonicotinoid pesticide, to diminished ability to echolocate among bats. They found that bats who fed on insects exposed to imidacloprid developed difficulty travelling on established paths and frequently became lost while hunting. The researcher noted “When toxic substances accumulate to a certain level, they damage the bats’ neurons and destroy their echolocation system.”

Threats to bat species are particularly concerning because of their slow rate of reproduction. Bat mothers only give birth to a single pup each year. This renders bat populations particularly vulnerable to factors that might disturb food sources or prevent successful migration during mating season.

How to Protect the Species

Mexican long-tongued bats live in a range of environments including scrub and saguaro desert, deciduous, pine, and oak forests, and canyons. Preservation of these habitats as well as food sources is imperative to protect the future of the Mexican long-tongued bat. Similarly, insisting on habitat preservation and personally fostering food sources for your local bats is necessary to protect your regions species. Even if the Mexican long-tongued bat’s range doesn’t reach your region, there are many other species of bats who act as beneficial pollinators. Consult these species profiles to determine which bats contribute to pollination in your area.

It is also critical to avoid planting any seeds or flowers that have been coated in pollinator-toxic neonicotinoids. As established in the aforementioned study which linked imidacloprid to loss of ability to echolocate in bats, these chemicals can undermine your intent to provide habitat for wild pollinators. See Beyond Pesticides’ Pollinator Friendly Seed and Nursery Directory to source safe seeds. For more information, see the webpage on Managing Landscapes with Pollinators in Mind. You can also get active in your community to protect these pollinators by holding native planting days in the spring, and advocating for changes to community pesticide policies.

In addition to actively opposing destruction of habitat and food sources, you can provide personal support to local bat populations. One option is to install a bat house on your property. You can build your bat house yourself or order one online to provide non-traditional habitat for your region’s species.

Further, Mexican long-tongued bats and other bat species have been known to visit hummingbird feeders. If you do host a number of local species at your hummingbird feeder, refer to this recipe, endorsed by the Smithsonian’s National Zoo, to ensure the health of hummingbirds and bats alike. Make sure to use organic sugar to avoid exposing visitors to unnecessary pesticides. The Texas Parks and Wildlife Department supports the use of feeders to support bats which arrive too early in spring or which remain through the winter. However, they also note that sugar water, while helpful sustenance, will not support long-term survival of bats because it lacks important nutrients.

It is important to educate others to dispel the myths surrounding bats in your community. Bats are an important part of local ecosystems and play a large role in pollination and control of insect populations. There are only three species of bats feeding primarily on blood. These species are not found in the United States but have created a widespread fear around the larger 1,200 species order. Another myth is that bats are a common carrier of rabies. Bats, like all mammals, are capable of carrying rabies. However, infection is not widespread and the odds of a bat exposing you to rabies are very low. Know that individual bats who are active during daylight hours and those who are not disturbed when approached by humans are more likely to be infected. Remember, bats are wild animals and should only be handled by trained professionals. The organization Bat Conservation International has more information on bat myths here.

Citations

Chen, Chi-chung and Elizabeth Hsu, Research finds pesticide impairs echolocation ability in bats http://focustaiwan.tw/news/asoc/201701110013.aspx

Godínez-Alvarez, H., Valiente-Banuet, A. and Rojas-Martínez, A., 2002. The role of seed dispersers in the population dynamics of the columnar cactus Neobuxbaumia tetetzo. Ecology, 83(9), pp.2617-2629.International Union for Conservation of Nature, Redlist of Threatened Species: Choeronycteris mexicana   http://www.iucnredlist.org/details/4776/0

Pearson, Gwen, Tequila, Booze, and Bats https://www.wired.com/2014/06/tequila-booze-and-bats/

Smithsonian National Museum of Natural History, North American Mammals: Choeronycteris mexicana https://naturalhistory.si.edu/mna/image_info.cfm?species_id=43

Texas Parks and Wildlife Department, Mexican Long-tongued Bat http://tpwd.texas.gov/huntwild/wild/species/mexlong/

Texas Tech University, National Science Research Library, Mexican Long-tongued Bat https://www.depts.ttu.edu/nsrl/mammals-of-texas-online-edition/Accounts_Chiroptera/Choeronycteris_mexicana.php

USDA Forest Service, Bat Pollination https://www.fs.fed.us/wildflowers/pollinators/animals/bats.shtml

What Eats, What Eats a Bat? http://www.whateats.com/what-eats-a-bat

Winter, Y. and von Helversen, O., 2003. Operational tongue length in phyllostomid nectar-feeding bats. Journal of mammalogy, 84(3), pp.886-896.

Name

Tumbling flower beetle is the common name for Mordellidae, a family of beetles comprising over 1,500 species, 200 of which are found in North America according to the Field Guide to Beetles of California. Their common name is derived from the movement pattern they exhibit when disturbed. The beetles use their large rear legs to kick, jump, and tumble in an erratic pattern to the confusion of predators and the amusement of human observers.

Range

The differentiation in this large family lends itself to near ubiquity. According to the Encyclopedia of Life, the tumbling flower beetle can be found on every continent except Antarctica. Texas A&M notes the individual species are not overly adapted to specific environments and a number of species frequently overlap within a single ecosystem.

Diet and Pollination

Beetles are frequently overlooked in the world of pollinators. According to the United States Department of Agriculture’s Forest Service, the tumbling flower beetle’s ancestors were some of the earliest insects to utilize flowers for food and habitat. In doing so, these ancient pollinators began an important collaboration between flowers and beetles which continues today. Mature tumbling flower beetles feed on the pollen of flowering plants. They pollinate as they feed, transporting pollen on their body from a previous flower to successive locations. Idaho State University notes that beetles play a more important role in the pollination of tropical regions than in temperate ones. Even so, there are approximately 50 native plant species in the United States and Canada which depend upon beetle pollination.

Physiology

The large number of tumbling flower beetle species are unified by general appearance. Texas A&M describes the beetles as small, narrow, and wedge-shaped at just 1/4 inches long. Most species are black or dark brown but some are yellow or reddish and can exhibit thick bands, small stripes, and even spots. Their bodies are covered in fine hair which, in some species, becomes iridescent in sunlight. The tumbling action, for which the beetle is named, is caused by their jumping technique. They are equipped with large and strong rear legs for powerful jumping. Interestingly, they use a single leg of the rear pair to apply an uneven force to the ground and cause their body to both roll and somersault. According to the Encyclopedia of Life, the beetle uses this action to reposition its body for takeoff and may make successive tumbles until the correct position is achieved. Tumbling flower beetles are strong fliers but also frequently elect to tumble to the safety of ground from their perch.

Ecological Role

The guidebook Attracting Native Pollinators notes that the life cycle of the tumbling flower beetle revolves around the flowers it pollinates. With the onset of spring, the beetles reach maturity and begin to mate. In most species, the females lay their eggs in the stalk and stems of those same flowers. There, the larvae will develop and feed until the following spring when they emerge and repeat the process.  Some other species prefer to lay their eggs in decomposing wood where larvae play a limited role in recycling dead plant material. The tumbling flower beetle also plays an important ecological role as prey to other creatures. The article Bird predation and the host-plant shift by the goldenrod stem galler notes that downy woodpeckers and other birds eat tumbling flower beetle larvae. Adults are hypothesized to be prey to birds as well in A mordellid-meloid mimicry. Further, crab spiders are known ambush predators of a wide range of insects which frequent flowers.

Threats to Existence

The tumbling flower beetle family of species is currently thriving and is not listed on the International Union for Conservation’s Red List of Threatened Species. This means there is no evidence that the existence of the family is currently at risk. Even though the tumbling flower beetle is not in immediate danger, conservation efforts to protect its future should not be ignored. According to Kansas State University and Texas A&M, the tumbling flower beetle does little to no damage to crops and is not considered an agricultural pest. However, its larvae do bore into stalks and may be grouped with other stalk-boring insects which collectively cause crop damage. The crops which house the tumbling flower beetle larvae may be treated with pesticides targeting more destructive insects to the detriment of tumbling flower beetle populations. However, the stem-boring habit of the larvae generally protects them from non-systemic pesticides.

How to Protect the Species

There are steps that can be taken to ensure that the tumbling flower beetle continues to thrive. Noted favorite plants in the Field Guide to Beetles of California are buckwheat and sunflowers. Texas A&M suggests the composite and umbelliferous flower families are also popular. Planting these preferred varieties of flowers is a great way you can support the tumbling flower beetle. They will use the plants’ stems to host their larvae and their pollen as a food source. The females will insert their eggs beneath the skin on stems. According to Kansas State University, as many as 40 larvae may be distributed throughout the plant in this way. Avoiding the use of pesticides is paramount in protecting beneficial pollinators in your area. Tumbling flower beetles can be exposed by interacting with plants, soil, or air that have been subjected to pesticides. You should be aware of the chemicals used in your gardening solutions and avoid buying products that that contain neonicotinoids, a class of chemicals linked to pollinator declines. For more information on the impact pesticides have on non-target organisms read Beyond Pesticides’ report on Bees, Birds, and Beneficials, which can be found here. Switching to organic means of pest control around your home and garden is the best way to protect the health of pollinator populations in your community. For more information on how you can get involved in pollinator conservation throughout the nation, see Beyond Pesticides BEE Protective webpage.

Citations:

Deyrup, M. and Eisner, T., 1987. A mordellid-meloid mimicry. Psyche (Cambridge, Massachusetts), 94(3), pp.215-218. http://biostor.org/reference/175288

Encyclopedia Britannica https://www.britannica.com/animal/tumbling-flower-beetle

Encyclopedia of Life http://eol.org/pages/399/overview

Evans, Arthur V. and Hogue, James M., Field Guide to Beetles of California. Click here to see citation.

Idaho State University https://www.isu.edu/biology/potential-pollinating-insects/beetles/

Kansas State University, Department of Entomology http://entomology.k-state.edu/extension/insect-information/crop-pests/sunflowers/tumbling-flower-beetle.html

Morse, D.H., 1986. Predatory risk to insects foraging at flowers. Oikos, pp.223-228. https://www.jstor.org/stable/3548353?seq=1#page_scan_tab_contents

Poff, A.C., Haynes, K.J., Szymanski, M., Back, D., Williams, M.A. and Cronin, J.T., 2002. Bird predation and the host-plant shift by the goldenrod stem galler. The Canadian Entomologist, 134(02), pp.215-227 http://www.jcronin.biology.lsu.edu/publications/canent02.PDF

Shepherd, Matthew and Vaughn, Mace, Attracting Native Pollinators. Click here to see citation.

Texas A&M Agrilife Extension https://texasinsects.tamu.edu/tumbling-flower-beetle/

USDA Forest Service https://www.fs.fed.us/wildflowers/pollinators/animals/beetles.shtml

Name

The Fig wasp is a highly evolved pollinator crucial to the life cycle of the fig tree.  Part of the chalcidoid family, the Fig wasp is a member of the agaonidae sub family, which consists of both mutualistic pollinating, and parasitic, non-pollinating, fig wasps. 

Fig wasps have a mutually beneficially relationship with fig trees, as both the tree and the wasp rely on each other for reproduction.  According to the Encyclopedia Britannica, there are about 900 species of pollinating fig wasps that are responsible for pollinating 900 different fig tree species. The relationship between fig trees and fig wasps is so evolved that each type of fig wasp pollinates only one specific type of fig tree, creating a beautiful and interdependent evolutionary partnership.

Range

The range of the fig wasp is dependent on the range of fig trees, which, according to the Encyclopedia of Life, are mainly found in the tropical and subtropical areas of the southern hemisphere. The most widely known fig tree, the common fig tree, or Ficus carica, is native to southwest Asia and the Mediterranean, and range anywhere from Afghanistan to Portugal.  The strong demand and high commercial value of the fig fruit has led to the naturalization of the common fig tree in additional parts of the world that have the requisite mild and semi-arid climate required for the species to grow.  California, Oregon, Texas, Utah and Washington all commercially produce the common fig tree.

Western consumers predominately eat figs from the common fig tree. This is due largely to the fact that this variety does not require pollination to the same extent as other fig species, making them easy to grow at home or in climates without naturally occurring fig wasp populations. However, there are two species of fig wasps that have been introduced in North America, which are typically used to pollinate the commercially valuable Smyrna fig.

Diet, Pollination, and Life Cycle

The fig wasp, as mentioned earlier, exclusively coexists with fig trees, which makes the fig fruit their primary source of nutrition.  In order to understand the diet and method of pollination of the fig wasp it is important to understand their life cycle, which is heavily intertwined with the fig fruit. Fig wasps can be separated into two different groups, pollinating and non-pollinating, each of which plays an important role in the life cycle of a fig. Pollinating wasps provide a mutually beneficial service to the trees in the form of pollination, while non-pollinating wasps use the plant as a source of food, and often act as a parasites to either the fig plant or the pollinating wasps. 

The first stage in the fig wasp’s life cycle occurs when a female fig wasp first enters an unripe fig fruit through a small opening known as the ostiole, and travels to the synconium, or inner part of the fig fruit, which contains both male and female flowers. Once inside, she will lay her eggs in the shorter flower structures. The longer flower structures remain unfertilized and eventually develop into the seeds you see inside of a fig. While laying her eggs, the female fig wasp inadvertently pollinates the female flowers found inside the fig fruit by transferring traces of pollen particles from the fig fruit in which she originally hatched. Once their eggs are laid, female fig wasps die within the fig. 

As the fig fruit and the eggs mature, male wasps hatch and emerge from their eggs, known as galls, traveling within the fruit towards the synconium in search of females to fertilize. After doing his part to fertilize the female, a male fig wasp will begin digging escape tunnels for the females once they hatch, though he will never get to benefit from them himself, as males die within the fig fruit during this process. Because they never leave the fruit in which they were born, male fig wasps do not have wings.

As all of this is happening, the male flowers are maturing and creating pollen for the new batch of female fig wasps to transfer to the next fig fruit. Once the female hatches she makes her way through one of the escape tunnels dug by the males, picking up pollen from the male flowers in the process. With pollen now in tow via her body, the female emerges in search of a new fruit to lay her eggs in, pollinating another fig in the process and starting the cycle all over again. It is through this process that the highly specialized and enclosed flowers within the figs are pollinated, further demonstrating the interdependence between the life cycle of the fig wasp and the fig tree.

Physiology

Fig wasps are much smaller than common wasp species and more closely resemble a fruit fly, with body lengths reaching only 1-2 mm in length.  With around 900 different species of fig wasps there are physical differences from one species to the next due to coevolution with their host fig tree species.  Despite this highly evolved individuality, fig wasps do share some general some characteristics across the species.

Female fig wasps are larger in size than male fig wasps and, as mentioned above, females have wings while males do not, as they do not leave the fig within their life cycle.  However, because one of their primary roles is to create tunnels for female wasps to exit the fig, male fig wasps have strong, specialized mandibles built to chew through the fig’s tough outer flesh.  Females, on the other hand, are equipped with wings to travel to another fig tree or fig fruit to lay eggs. 

According to the Encyclopedia of Life the female fig wasp’s body has evolved over time to fit into the ostiole of the fig.  There are special appendages on her head that help her body inch through the tight opening on the fig.  Additionally, some species of female fig wasps have evolved to have an extremely long ovipositor, the body part responsible for laying eggs.  This allows the female to lay her eggs from the outside of the fig without entering and trapping herself within the fruit.  Fig wasps have very short life spans, living only between 1-2 days once hatched from their eggs.

Ecological Role

The fig wasp may seem like a menial pollinator given that they only pollinate one type of plant, but that is far from the case!  The fig wasp is an integral species, as the fig tree has been identified as a keystone species in tropical rainforests where they help maintain the population and diversity of a variety of species.  The Encyclopedia of Life defines a keystone species as “a species within the ecosystem that exerts a major influence on the composition and dynamics of the ecosystem of which it lives.”  This means that the fig tree is a species that has a disproportionally large effect on its environment, relative to its abundance within the ecosystem.  

Many species rely on the fig fruit and its leaves as their main source of nutrients.  The Encyclopedia of Life lists the fig as a key resource for many fruit eating animals including fruit bats, several species of monkeys, and a plethora of birds.  Insects like caterpillars, moths and beetles all feed on the leaves of the fig tree. In fact, over 1,200 different species of birds and mammals have been recorded to eat fig fruits.

Threats to Existence and How to Protect Species

Currently the fig wasp and the fig tree are not in immediate danger, however some scientists are concerned that climate change and global warming could have a negative impact on fig wasp populations.  In a study done in Singapore in 2013, researchers studying fig wasps discovered that fig wasp survivability drastically reduced in climates that were warmer than their desired habitats.  More extreme climates could threaten the productivity of fig wasps, possibly causing a decline in fig tree populations.  They hypothesize that as climate change continues to intensify, the insects will alter their behavior in order to adapt to warmer climates. However, if the changes in temperature take place too quickly for these adaptations to occur, it could conceivably threaten the existence of the fig wasp.

Tropical rainforest deforestation also poses a threat to fig wasps.  As human development and agricultural activity continues to expand, forests around the world are being cleared at alarming rates, especially in developing countries where most of the world’s tropical rainforests are located.  Fig trees and their companion pollinators are incredibly important to rainforest ecosystems, as they provide a popular source of food and attract seed dispersing animals.

There are a few things that can be done within your community to protect and foster fig wasps and fig tree populations.  For starters, if you live in an area with an appropriate climate, consider planting a fig tree in your yard, garden, or community! The next vital step in protecting fig wasps and fig trees is to avoid the use of pesticides in your community.  You should be aware of the chemicals used in your gardening solutions and avoid buying products that that contain neonicotinoids, a class of chemicals linked to pollinator declines. Neonicotinoids are systemic by nature, and if sprayed near a fig tree could be transported through the roots into the flower of the plant, threatening the fig wasps who live inside. For more information on the impact pesticides have on non-target organisms read Beyond Pesticides’ report on Bees, Birds, and Beneficials, which can be found here.

Switching to organic means to control pests around your home and garden is the best way to protect the health of pollinator populations in your community.  For more information on how you can get involved in pollinator conservation throughout the nation, see Beyond Pesticides BEE Protective webpage.

Citations

Cook, James M. and West, Stuart A. Figs and Fig Wasps. Current Biology Vol 15, No 24. https://www.cell.com/current-biology/pdf/S0960-9822(05)01466-1.pdf

Encyclopedia Britannica https://www.britannica.com/animal/fig-wasp

Encyclopedia of Life (Fig Wasp) http://eol.org/pages/736/details

Encyclopedia of Life (Fig Tree) https://eol.org/pages/594632/

Jevanandam N, Goh AGR, Corlett RT. 2013 Climate warming and the potential extinction of fig wasps, the obligate pollinators of figs. Biol Lett 9: 20130041. http://dx.doi.org/10.1098/rsbl.2013.0041

Name

A quick flash of red and green will likely be the most you’ll see of the Ruby Throated Hummingbird.  They are one of nature’s most nimble and agile birds, hovering over flowers for just a second or less before moving on to the next.  The Ruby Throated Hummingbird, or Archilochus colubris, is the most abundant species of hummingbird specific to the eastern half of North America.  They are named after the coloration of ruby red feathers around their throat.

Range

The Ruby Throated Hummingbird is the most populous hummingbird found east of the Mississippi.  They enjoy mild habitats such as pine and deciduous forests, and can also be found zipping around urban and suburban gardens and orchards.  Ruby Throated Hummingbirds “winter,” meaning they migrate to warmer parts of the globe during the colder winter months.  They typically spend that time in parts of Central America and southern Mexico, but have been known to travel as far south as Costa Rica and the West Indies, according to Animal Diversity Web.  They will often migrate without stopping, traveling distances as great as 1600 km in one trip.

According to the Encyclopedia of Life, the hummingbird’s mating grounds are typically east of the 100^th meridian in the United States and parts of southern Canada.  Their ability to inhabit such a diverse range of habitats make them an important pollinator to many ecosystems across eastern North America.

Diet and Pollination

Nectar from flowering plants comprises the majority of the Ruby Throated Hummingbird’s diet, but fat and protein are supplied by small insects, including mosquitoes, spiders, gnats, fruit flies, and small species of bees. They have also been observed eating tree sap, and their northern limit is probably determined by the availability of sap provided by the drilling of sapsuckers.

According to the Encyclopedia of Life, Ruby Throated Hummingbirds have adapted to be able to see the UV spectrum of light in addition to the visible light spectrum, which helps them locate and differentiate between a variety flowers. Their favorites include:  Red Buckeye, Jewel Weed, Trumpet Creeper, Red Morning Glory, Coral Honeysuckle and the Cardinal Flower, just to name a few.

Physiology

Most hummingbirds are small statured compared to their other avian counterparts, and the Ruby Throated Hummingbird is no exception. Ranging in length from 7 to 9 cm and weighing only a few grams, the bird can easily fit in the palm of your hand.  Their incredible flying abilities are attributed to their lightweight and stream line bodies. Spectacular as those abilities are, however, they can be taxing on the bird and require a lot of energy. Because of this, the Ruby Throated Hummingbird will consume twice their body weight in food each day.

Ruby Throated Hummingbird’s coloration is striking, featuring beautiful shades of green, white and red. Males can be distinguished from females by their tail feathers, as males have a forked feather configuration while females boast a square feather configuration with white tips. Males additionally have the characteristic red, ruby throat while females will have a duller, grayish-red colored throat. Females are larger than their male counterparts.

Ruby Throated Hummingbirds are migratory birds, returning to their breeding grounds in eastern North America each spring. Males generally return to the breeding grounds ahead of females to stake out their territory for mating. Once a female enters a male’s territory, the male bird will court the female with a dive display meant to impress the female. As part of this display, the male will do a variety of loops and acrobatic flying maneuvers, beating its wings up to 200 times per second. After successful breeding, the female constructs a nest for her eggs out of bud scales and lichen, held together with spider’s silk and lined with plant down. There the female will lay one to three eggs, which are incubated for 10-14 days before they hatch, a cycle that is repeated two or three times per breeding season. The average lifespan of the Ruby Throated Hummingbird is about nine years.

Ecological Role

Ruby Throated Hummingbirds live on a diet of nectar from a variety of flowering plants and, as previously stated, consume up to twice their bodyweight in nectar each day. This requires constant foraging for sources of nectar and the birds spend most of their day flying flower to flower in search of this food source. They are equipped with a long, skinny modified beak that allows them to access nectar, as well as a long tongue that can further be extended into the flower.

While foraging for nectar the hummingbird simultaneously contaminates itself with pollen particles from the flower. The pollen sticks to the birds’ feathers and beak, allowing the bird to transport it to the next flower it visits. Once that pollen comes in to contact with a new flower, the plant is inadvertently cross-pollinated, allowing the plant to reproduce. The abundance of Ruby Throated Hummingbirds make them an integral pollinator to ecosystems across the eastern United States and parts of Canada. Partners for flight, an organization that tracks land birds for conservation purposes, estimates the Ruby Throated Hummingbird population in North America and Canada is as great as 34 million.

Threats to Existence

The Ruby Throated Hummingbird is currently a thriving species, labeled as a species with “Least Concern” by the International Union for Conservation. This simply means their existence is not currently at risk. The United States Geological Service Patuxent Wildlife research center, which has been tracking land bird species since the 1960’s, has found that Ruby Throated Hummingbird populations have been on the rise since their studies began. Even though the species is not currently at risk, however, conservation efforts to protect the birds’ future success should not be ignored. Destruction of natural habitat is a primary risk that can affect the hummingbird’s ability to prepare for migration, as well as diminish the bird’s breeding grounds and disrupt its reproductive success. The bird’s exposure to systemic pesticides that move through a plant’s vascular and is expressed in nectar is of particular concern.

How to Protect the Species

There are steps that can be taken to protect Ruby Throated Hummingbirds, one of the most popular being to install a hummingbird feeder in your yard or garden. Simple actions, like placing your hummingbird feeders away from windows to prevent collisions, or situating feeders in places where cats and other neighborhood predators will have a difficult time reaching the birds, are important ways to help hummingbirds thrive.  Routine cleaning of hummingbird feeders is also important, as rancid feeders can be detrimental to hummingbird health. Supplying your hummingbird feeder with the right nectar solution is also important. You can find a trusted nectar recipe recommended by the Smithsonian National Zoo by clicking here!  Be sure to use organic sugar in your mix, as it will ensure that your nectar solution is free of pesticides and additives.

Planting the aforementioned flowers preferred by the Ruby Throated Hummingbird is another way you can preserve hummingbird populations, as they require nectar for survival.  Avoiding the use of pesticides is also paramount in protecting bird populations in your backyard.  Birds can be exposed to pesticides indirectly through the ingestion of insects that have been in contact with pesticides, or directly by interacting with plants that have been subjected to pesticides. You should be aware of the chemicals used in your gardening solutions and avoid buying products that that contain neonicotinoids, a class of chemicals linked to pollinator declines. For more information on the impact pesticides have on non-target organisms read Beyond Pesticides’ report on Bees, Birds, and Beneficials, which can be found here.

Switching to organic means to control pests around your home and garden is the best way to protect the health of bird populations in your community.  For more information on how you can get involved in pollinator conservation throughout the nation, see Beyond Pesticides BEE Protective webpage.

Citations

Animal Diversity Web, Encyclopedia of Life, The Birder's Handbook by Paul Ehrlich, David Dobkin, and Darryl Wheye (1988).

Name

Over 5,000 species of Bombyliidae (Bee Flies), a large family within the order Diptera, can be found across the globe. While few of these species have been researched in great depth, they all have similarities that tie them to their classification. The vast majority of Bee Fly species have larvae that are parasitoids, and all adults feed on a diet of pollen and/or nectar, making them important pollinators.

Photo by AJC1 on Flikr

Range

Bee Flies have been discovered on every continent but Antarctica. The most diverse group of species can be found in semi-arid and arid (desert) environments such as western North America, southern parts of South America, along the equatorial lines of Africa, and the mid latitudes of Eurasia.

Diet and Pollination

Most Bee Flies in their larval stage are parasitoids to the larvae of other soil-inhabiting insects. As opposed to parasites, which usually live off their host, but do not always cause death, parasitoids like the Bee Fly always kill their host. According to the World Catalog of Bee Flies, larvae of some Bombyliidae species prey on major agricultural pests, such as locusts, grasshoppers, armyworms, slugs, and caterpillars. However, select species have been found to be parasitoids of other pollinators like solitary bumblebees. And a small number species of Bee Fly larvae simply prey on insect eggs.

Most adult Bee Flies, once fully mature, feed on nectar from a variety of native flowering plants. Females are required to consume pollen in order to provide the protein and nourishment necessary for the development of eggs and reproduction. Bee Flies are thought to be responsible for what are called “pollination syndromes,” meaning many native flowering plants coevolved and adapted with Bee Flies.

Physiology

Adult Bee Flies are adapted for a pollen and nectar diet, and their physiology shows it. They have small bodies which range in length from 1mm to 2.5cm, depending on the species. Their wingspan can be as small as 1.5mm, though larger species can have a span of more than 60mm.  Many species utilize biomimicry, in terms of their coloration, often resembling bees (hence their common name as the Bee Fly) or wasps. This offers them protection, as their predators assume that they have the temperament of a more aggressive species. Nonetheless, some species simply have a solid coloration of grey or rusted brown. Bee Flies’ wings appear swept back when at rest, and their legs are generally long and skinny compared to their body, with bristles at the ends. Many Bee flies are equipped with a very long proboscis (tubes that enable them to lap up nectar) that allows them to collect nectar from flowers with long narrow floral tubes. The Bee Flies’ proboscis is fixed, and cannot be retracted, giving it a tusk-like resemblance.  

Ecological Role

Bee flies play an important ecological role as pollinators, particularly for flowering desert plants in the U.S. Southwest. Although the Bombyliidae family is understudied, the World Catalog of Bee Flies notes that because many flowering plants require Bee Fly pollination in order to propagate, some endangered plant species are likely reliant on the conservation of certain bee fly species. In addition to providing valuable pollinator services as adults, as noted earlier, Bee Fly larvae can play an important role in pest control. In addition to controlling agricultural pests like slugs and locusts, some species prey on the tste fly, which are infamous for their ability to transmit human diseases like trypanosomiasis, or sleeping sickness.

Threats to Existence

A literature review by the Bureau of Land Management (BLM) notes, “At any single locality a population of bee flies may be considered to be endangered, but throughout the desert areas they may not appear to be so because of their apparent wide distribution.” Because their interaction between specific flowers and certain Bee Fly species is so closely intertwined, habitat loss represents a significant threat to the Bombyliidae family. BLM’s literature review provides an example of the importance of maintaining habitat in the Algodones Dunes near Imperial County, CA. Areas open to recreational vehicles like ATVs resulted in the loss of a majority of flowering plants. While Bee Fly numbers in these areas became locally extinct, areas adjacent to the recreational area maintained their population numbers.

Pesticides, particularly persistent, systemic neonicotonoid insecticides, also represent a serious threat to many Bombyliidae species. Because many species feed on agricultural pests, they are more likely to be exposed to pesticides in these areas. Although the impacts of neonicotinoids and other pesticides on wild pollinator species are understudied when compared to investigations on honey bees, research that has been performed is cause for concern.

How to Protect the Species

There are a few simple ways to protect Bee Fly populations. Providing habitat by planting native flowers is an important first step for Bombyliidae conservation. Providing native habitat is especially important for individuals in arid or semi-arid regions of the U.S. Southwest, and these flowers are relatively easy to maintain as they do not require a lot of water and there is plentiful sun.

It is also critical to avoid planting any seeds or flowers that may be coated in pollinator-toxic neonicotinoids, as these chemicals can undermine your intent to provide forage and habitat for wild pollinators. See Beyond Pesticides’ Pollinator Friendly Seed and Nursery Directory as a starting place. And for more information, see the webpage on Managing Landscapes with Pollinators in Mind. You can also get active in your community to protect these pollinators by holding native planting days in the spring, and advocating for changes to community pesticide policies. Lastly, by buying organic, you can support an agricultural system that eschews the use of toxic pesticides like neonicotinoids that harm native pollinators.

For more information on how you can get involved in pollinator conservation throughout the nation, see Beyond Pesticides BEE Protective webpage.

Citation/Additional Resources

Evenhuis, N.L. 2015. World catalog of bee flies (Diptera: Bombyliidae) web site. http://hbs.bishopmuseum.org/bombcat/

Hall, J. 1979. Review of literature and museums for groups of the bombyliidae, bee flies, and outline of the districution fo rate and potentially endangered species in the California Desert Conservation Area. http://www.biodiversitylibrary.org/item/121097#page/1/mode/1up

Yeates, D and Lambkin, C. 2004. Tree of Life web project. http://www.tolweb.org/Bombyliidae