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Celebrating Our Unsung Pollinator Heroes

When it comes to pollination, bees tend to get all of the buzz. While they are crucial to pollinating many crops, it is important to note that bees aren’t the only pollinators working hard to provide the ecosystem services we rely on to support our food system. In fact, one out of every three bites of food we take is made possible by pollinators. In order to raise awareness for the unsung pollinator heroes all around us, Beyond Pesticides created the Polli-NATION Campaign, which highlights the important work of a relatively unknown pollinator each month. With it, we will raise public awareness about these pollinators, their contribution to plant health and productivity and the preservation of natural resources, and the threats they face in their daily lives, including toxic pesticides and habitat loss. Polli-NATION members include species like butterflies, wasps, flies, beetles, birds, bats, and more. By taking the time to read about our featured Polli-NATION pollinator, you will not only learn about the many diverse species we call pollinators, but also discover what you can do in your daily life to help ensure their survival.

February 2017: Ruby Throated Hummingbird

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 100th 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).

January 2017: Bee Flies

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