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Benefits of Bats

With more than 1,400 species of bats worldwide, over 40 species in the U.S. alone, and in making up 25% of the world’s total mammal population, these nocturnal flying creatures have quite a large footprint. As the Bat World Sanctuary (BWS) shares, “Consider this: if your day includes soap, shampoo, cosmetics, a toothbrush and toothpaste, coffee, margarine, paper or ink, cushions, wood furniture, fuel or lubricating fluids, sisal used to make rope and twine, timber, boats or canoes, ornamental trees, life saving medicines, air fresheners, candles, rubber, chewing gum, spices, vegetables, fruits, chocolate or even margaritas or beer, you are not only involved with bats, you are dependent upon bats.” 

Ecosystem Services 

Bats, among other wildlife including birds and bees, provide important ecosystem services through pollination, management of pest populations, and contributing to plant resilience and productivity. The importance of bat species and their services cannot be understated. Bats are the only nocturnal insect predator in the U.S. and are one of two primary nocturnal pollinators (along with moths) — important roles for night-flowering plants and for farmers.  

Bats are one of many under-appreciated pollinators, but bat pollination, technically known as chiropterophily, is integral for many wild and commercial tropical fruits. Pollination occurs when the bats feed from nectar and collect pollen in their fur that they then transport to numerous other flowers. Indeed, over 500 plants worldwide are completely or partially dependent on bat pollination. The next time you eat a guava, avocado, fig, peach, clove, cashew, or mango you might want to thank the bats.  

Seed dispersal is another important service bats provide. “Some seeds will not sprout unless they have passed through the digestive tracts of a bat. Bats spread millions of seeds every year from the ripe fruit they eat... Fruit bats are responsible for 98% of the reforestation of the world’s rain forests (the lungs of our planet). Without fruit bats we would lose entire forests without felling a single tree,” BWS notes.  

Bats’ pest control services—relatively invisible because they do their insect marauding at night when humans are not watching—represent an excellent nontoxic, biological control for some agricultural pests, as well as for mosquitoes that may be human disease vectors. This highlights the public health benefits from bats, as they lower health care costs by reducing toxic pesticide use on chemical farms and in their ability to lower the rate of mosquito borne disease. Bats are also incredibly useful in the study of emerging viral diseases such as coronaviruses, and add an inherent, existential value to natural landscapes. 

These organisms not only consume mosquitoes that can carry diseases, such as West Nile virus, Eastern equine encephalitis (EEE), Zika virus, malaria, dengue fever, yellow fever, and others, but their management of pests protects millions of dollars in agriculture. As declines in bat populations and other pollinators continue to occur, it is becoming increasingly clear that the ecosystem services provided by bats cannot be adequately replaced by human activities. These species are both integral to biodiversity as well as agricultural production. 

Approximately 70% of bat species are insectivores, including pests that consume the crops we rely on for food. The two species of brown bats (the “big” and the “little”) most common in the U.S. are voracious, consuming 3,000–7,000 insects per night. “Who needs pesticides when we have bats?,” Bat Conservation International says. They continue: “Scientists estimate that insect-eating, or insectivorous, bats may save U.S. farmers roughly $23 billion each year by reducing crop damage and limiting the need for pesticides. Most, on average, can eat up to half their body weight in insects, while pregnant or nursing mothers will consume up to 100 percent of their body weight each night.” Adding to this, BWS states, "The 20 million bats that roost at Bracken Cave in Texas, eat 200 tons of insects each summer evening. They eat crop pests that cost farmers billions of dollars annually. Insect control by bats keeps down prices of fruits and vegetables in the market place.” 

Bats and Pesticides 

Bats are also considered an “indicator species,” meaning that they interact with many elements of their environment and that their well-being is a barometer for the health of those ecosystems. While degradation of ecosystems is attributable to many factors, pesticide use accounts for an important element in harm to bats and overall biodiversity. Bats also tend to have only one offspring each year, making them vulnerable to the population impacts of negative reproductive effects caused by pesticides, because low reproductive rates require high adult survival rates to avoid population declines. 

Because bats are unusually long-lived for animals their size—with lifespans ranging from 20 to 40 years—their bodies can accumulate pesticide residues over a lengthy period, exacerbating adverse effects associated with those pesticides that can accumulate in fatty tissue. Also, during migrations or winter hibernation (when their fat stores are metabolized), bats’ consumption of large volumes of pesticide-contaminated insects can mean that these compounds may reach toxic levels in their brains — making them more susceptible to white-nose syndrome (WNS), a fungal disease that impacts several cave-dwelling bat species.  

This invasive fungus (Pseudogymnoascus destructans), as highlighted in an article in the New York Times, has caused three species of bats in North America to be decimated by this syndrome, and bats with WNS have been confirmed in 40 states and nine Canadian provinces. WNS causes bats to behave uncharacteristically by waking up more frequently during the winter and flying during the day. These changes use up their limited fat reserves too quickly, leaving them debilitated. WNS has killed millions of bats since the introduction of the fungal disease in 2006. In just the first five years from onset, scientists estimated between five and seven million bats died as a result of WNS. 

According to bat experts, as of 2023, 52% of bat species in North America are at risk of severe declines over the next 15 years. With the collapse of many bat populations from WNS, farmers turn to toxic chemicals to replace the ecosystem services bats usually provide. These chemicals, however, lead to ripples throughout the ecosystem and create a cyclic problem for bat species. By further suppressing their immune systems, it only adds to their susceptibility to WNS.  

Additionally, when insect-eating bats encounter food exposed to pesticide treatments, the pesticides can diminish their ability to echolocate, causing them to travel on less established paths and frequently become lost while hunting. Preservation of habitats frequented by bats, including scrub and saguaro desert; deciduous, pine, and oak forests; and canyons, as well as their food sources within those environments, is imperative to protect the future of all bat species.

Resources 

Scientific Studies

Precision foraging: Bats in organic desert palm plantations hunt where it is most needed. (Russo, D. et al. 2025) Bats are crucial in suppressing pest arthropods in agroecosystems, contributing vitally to sustainable agriculture. However, the importance of bats in agriculture in extreme environments, such as deserts, has received far less attention. Date palm plantations represent one of the few productive systems in hyper-arid regions. We studied habitat use in an organic date palm plantation in the Arava Valley (Southern Israel) employing acoustic surveys to assess bat activity and foraging behaviour. According to our predictions, bats preferentially foraged in the plantation’s most productive areas, with most of the 13 recorded species exhibiting significant activity in older, sheltered plots. Higher wind speeds correlated with decreased foraging across most species, but sheltered habitats often buffered this effect. While species richness remained stable across habitats, according to our prediction, activity levels varied according to habitat type and wind conditions. In general, bat activity increased in old productive plots in the plantation’s core section and decreased elsewhere in response to strong winds. These results highlight the importance of maintaining older productive areas within the interiors of date palm plantations to support bat populations and enhance their pest-suppressing roles. Management strategies should design wind-buffering plantations to protect critical bat foraging areas and provide water sources. As date palm plantations act as "oases" in unproductive landscapes, many bats likely travel significant distances to forage there. Protecting bat habitats on a large scale and prioritising multiscale conservation is crucial to preserving bats and their ecosystem services.

To improve or not to improve? The dilemma of “bat-friendly” farmland potentially becoming an ecological trap. (Russo, D. et al. 2024) Conventional agriculture occupies a substantial portion of Earth’s terrestrial surface and adversely affects biodiversity through pesticide spread, mechanisation, and loss of spatial and temporal heterogeneity of farmed landscapes. Consequently, conventional agriculture has become a primary target of many restoration projects operating at various scales, from habitat to landscape. While these restoration efforts aim to increase farmland biodiversity and promote the delivery of associated ecosystem services, unintended consequences may arise when important threats are not mitigated. For instance, animals may be led to make maladaptive choices, and lured to attractive sites with poor habitat quality (ecological traps), resulting in adverse effects on individual fitness and demography. We focus our review on European farmland as a case study because of its extensive presence on the continent and the particularly articulated legal framework regulating agriculture and biodiversity within the European Union. Europe's policy framework is dual-faced: one promotes farmland development regardless of management practices, while the other advocates for biodiversity protection measures that sometimes lack strong supporting evidence or overlook critical management aspects. Insectivorous bats contribute significantly to ecosystem service delivery through insectivory in agricultural landscapes, consuming large numbers of pest arthropods. However, when restoring habitats for bats in conventional farmland, potential unintended outcomes must be considered, particularly if restoration actions are not accompanied by mitigation of key threats. These threats include the persistent and widespread use of pesticides, road networks, the siting of wind turbines in farmed landscapes, and opportunistic predators, especially domestic cats. We argue that installing bat boxes and enhancing habitat and landscape features, such as increasing connectivity and diversity, potentially trap bats in attractive yet unsuitable environments if such threats are not mitigated. While environmental restoration in farmland is highly valued for supporting bat populations, it is crucial to avoid neglecting factors that could have the opposite effect, turning 'improved' farmland into a sink. Research is urgently needed to understand such potential unintended effects and inform farmland management and policymakers. 

A bat a day keeps the pest away: Bats provide valuable protection from pests in organic apple orchards. (Ancillotto, L. et al. 2024) Organic farming is an essential component of sustainable agriculture that can help maintain biodiversity in agricultural landscapes, providing benefits for both human well-being and environmental conservation. Recent studies have highlighted the vital role of insectivorous bats in farmland ecosystems in controlling pest insect populations. Our research focuses on the direct economic value of bat insectivory in woody crops, specifically in apple orchards affected by the codling moth Cydia pomonella. We conducted an exclusion experiment followed by an economic evaluation to estimate the impact of bat insectivory on crop damage and economic savings. Our results demonstrate that the presence of bats in apple orchards can significantly reduce the damage caused by C. pomonella, resulting in a 32.1% reduction in affected apple trees and a 50% reduction in the total weight of damaged apples per tree. This translates to estimated economic savings of 551 €/ha/y by reducing the need for insecticide applications and, consequently, minimizing the negative impacts of such chemicals on the environment and human health. Moreover, the presence of bats can lead to higher crop yields and protect the quality of the product, resulting in higher profits for farmers. Our findings highlight the critical role of bats in maintaining ecosystem services and provide valuable information for the sustainable management of farmland ecosystems. 

The economic impacts of ecosystem disruptions: Costs from substituting biological pest control. (Frank, E. 2024) Scientists have long theorized that declines in biodiversity and continued degradation of ecosystem functioning would lead to meaningful negative impacts on human well-being. Quantifying those impacts is challenging because of the limited measurements available on wildlife and plant populations as well as the ethical and feasibility constraints involved with randomly manipulating ecosystems at scales that would allow for the testing of key theoretical predictions. This work makes a contribution to our understanding of the relationship between ecosystem functioning and human well-being by using a natural experiment—an occurrence resulting from unexpected changes in environmental conditions that approximates a randomized control trial. Specifically, I use the sudden emergence of a deadly wildlife disease in insect-eating bats—known as white-nose syndrome—to quantify the benefits from their provision of biological pest control. I validate previous theoretical predictions that farmers respond by substituting bats with insecticides; however, because those are toxic compounds, by design, this substitution leads to higher human infant mortality rates in the areas affected by the bat die-offs.

Pest suppression by bats and management strategies to favour it: a global review. (Tuneu-Corral, C. et al. 2023) Fighting insect pests is a major challenge for agriculture worldwide, and biological control and integrated pest management constitute well-recognised, cost-effective ways to prevent and overcome this problem. Bats are important arthropod predators globally and, in recent decades, an increasing number of studies have focused on the role of bats as natural enemies of agricultural pests. This review assesses the state of knowledge of the ecosystem services provided by bats as pest consumers at a global level and provides recommendations that may favour the efficiency of pest predation by bats. Through a systematic review, we assess evidence for predation, the top-down effect of bats on crops and the economic value of ecosystem services these mammals provide, describing the different methodological approaches used in a total of 66 reviewed articles and 18 agroecosystem types. We also provide a list of detailed conservation measures and management recommendations found in the scientific literature that may favour the delivery of this important ecosystem service, including actions aimed at restoring bat populations in agroecosystems. The most frequent recommendations include increasing habitat heterogeneity, providing additional roosts, and implementing laws to protect bats and reduce agrochemical use. However, very little evidence is available on the direct consequences of these practices on bat insectivory in farmland. Additionally, through a second in-depth systematic review of scientific articles focused on bat diet and, as part of the ongoing European Cost Action project CA18107, we provide a complete list of 2308 documented interactions between bat species and their respective insect pest prey. These pertain to 81 bat species belonging to 36 different genera preying upon 760 insect pests from 14 orders in agroecosystems and other habitats such as forest or urban areas. The data set is publicly available and updatable. 

The Contribution of Desert-Dwelling Bats to Pest Control in Hyper-Arid Date Agriculture. (Schäckermann, J. et al. 2022) Over 40% of the Earth’s surface has been converted to agricultural use and agroecosystems have become important habitats for wildlife. In arid regions, intensive agriculture creates artificial oasis-like habitats due to their high irrigation inputs. Date production is one of the primary agricultural practices in the deserts of the Middle East and North Africa. Insectivorous bats are known to use agricultural areas, but the role of date plantations as their foraging habits and the importance of insectivorous bats as date bio-pest control agents are still unknown. We assessed the role of date plantations as foraging habitats for local desert bat species by acoustically recording bat activity in conventional and organic date plantations in the southern Arava Valley, Israel. In addition, we captured bats in the plantations and collected feces for DNA metabarcoding analysis to investigate the presence of pest species in their diets. We found that 12 out of the 16 known species of bats in this region frequently used both conventional and organic date plantations as foraging habitats. Species richness was highest in the organic plantation with complex ground vegetation cover. Foraging activity was not affected by plantation type or management. However, bat species richness and activity increased in all plantations during summer date harvesting. Molecular analysis confirmed that bats feed on a variety of important date pests, but the particular pests consumed and the extent of consumption varied among bat species. Our results highlight a win–win situation, whereby date plantations are an important foraging habitat for desert bats, while bats provide bio-pest control services that benefit the date plantations. Therefore, date farmers interested in bio-pest control should manage their plantations to support local desert bat populations. 

Bats provide a critical ecosystem service by consuming a large diversity of agricultural pest insects. (Maslo, B. et al. 2021) Biodiversity directly influences the delivery of multiple ecosystem services, most notably within agriculture. Projected future global demands for food, fiber and bioenergy will require enhancement of agricultural productivity, but favoring biodiversity-based ecosystem services generally remains underutilized in agricultural practice. In addition, agricultural intensification is a key driver of biodiversity loss. A significant obstacle preventing the adoption of ecologically sensitive practices is a lack of knowledge of the species delivering the services. Insectivorous bats have long been suggested to regulate insect pest populations and may be a critical component of biodiversity-based ecosystem services. Bats may also serve as agents of insect pest surveillance through environmental DNA (eDNA) monitoring approaches. However, the biological and economic importance of bats to agriculture remains under-quantified. Here we catalogued the dietary niche of two North American bats, little brown bat (Myotis lucifugus) and big brown bat (Eptesicus fuscus), through DNA metabarcoding of guano collected from seven roosting sites over a 26-week period. We measured the frequency of occurrence of known pest species in guano samples, compared interspecific differences in diet, and examined seasonal patterns in prey selection. Overall, we detected 653 unique prey species, 160 of which were known agricultural pests or disease vectors. Species diversity of prey species consumed varied by bat species and across the season, with big brown bats accounting for the majority of arthropod diversity detected. However, little brown bats consumed relatively more aquatic insects than big brown bats, suggesting that increased bat species richness in a landscape can amplify their net pest regulation service. Further, we hypothesized that detection probabilities of target insect pests would be higher in guano samples than in conventional survey methods. Multi-survey occupancy modeling revealed significantly lower detectability in bat guano than in conventional monitoring traps, however, highlighting important tradeoffs in selection of survey methods. Overall, the results presented here contribute to a growing evidence base supporting the role bats play in the provisioning of biodiversity-based ecosystem services. 

Insectivorous bats provide significant economic value to the Australian cotton industry. (Kolkert, H. et al. 2021) Insectivorous bats exert top-down pressure on pest insect populations in agricultural systems globally. However, few economic estimates exist of their value as pest control agents in many high value crops. We calculated the economic benefit of direct predation of insect pests by bats and the damage averted to cotton yield, a high value commodity crop in Australia. Using a combination of bat dietary studies, average daily energy requirements (estimated by field metabolic rate), prey energy content and acoustic data of bat feeding attempts in cotton crops, we show the direct value of insectivorous bats to the Australian cotton industry is likely between $99–126 ha−1 in dryland Bt-cotton and $286–361 ha−1 in irrigated Bt-cotton through the consumption of pest moth Helicoverpa armigera, amounting to $63.6 million annually. We estimate that a population of bats can remove between 77–119 t of moths from Australian cotton crops in an average year across the growing season. However, different bat species consume different insect pests, highlighting the need to conserve bat diversity in agroecosystems. These results provide further incentive for growers to manage non-crop bat roosting habitat to benefit from natural pest control in crops. 

An appetite for pests: Synanthropic insectivorous bats exploit cotton pest irruptions and consume various deleterious arthropods. (Cohen, Y. et al. 2020) Conservation biological control (CBC) seeks to minimize the deleterious effects of agricultural pests by enhancing the efficiency of natural enemies. Despite the documented potential of insectivorous bats to consume pests, many synanthropic bat species are still underappreciated as beneficial species. We investigated the diet of Kuhl's pipistrelle (Pipistrellus kuhlii), a common synanthropic insectivorous bat that forages in urban and agricultural areas, to determine whether it may function as a natural enemy in CBC. Faecal samples of P. kuhlii were collected throughout the cotton-growing season from five roost sites near cotton fields located in a Mediterranean agroecosystem, Israel, and analyzed using DNA metabarcoding. Additionally, data on estimated abundance of major cotton pests were collected. We found that the diet of P. kuhlii significantly varied according to sites and dates and comprised 27 species of agricultural pests that were found in 77.2% of the samples, including pests of key economic concern. The dominant prey was the widespread cotton pest, the pink bollworm, Pectinophora gossypiella, found in 31% of the samples and in all the roosts. Pink bollworm abundance was positively correlated with its occurrence in the bat diet. Furthermore, the bats’ dietary breadth narrowed, while temporal dietary overlap increased, in relation to increasing frequencies of pink bollworms in the diet. This suggests that P. kuhlii exploits pink bollworm irruptions by opportunistic feeding. We suggest that synanthropic bats provide important pest suppression services, may function as CBC agents of cotton pests and potentially contribute to suppress additional deleterious arthropods found in their diet in high frequencies. 

Effects of imidacloprid, a neonicotinoid insecticide, on the echolocation system of insectivorous bats. (Wu, C. et al. 2020) Imidacloprid, a widely used neonicotinoid insecticide, has led to a decline in the honey bee population worldwide. An invertebrate insect prey with neonicotinoid toxicity can adversely affect insectivores, such as echolocating bats. The aim of the current study was to examined whether imidacloprid toxicity may interfere echolocation system such as vocal, auditory, orientation, and spatial memory systems in the insectivorous bat. By comparing the ultrasound spectrum, auditory brainstem-evoked potential, and flight trajectory, we found that imidacloprid toxicity may interfere functions in vocal, auditory, orientation, and spatial memory system of insectivorous bats (Hipposideros armiger terasensis). As suggested from immunohistochemistry and western blots evidences, we found that insectivorous bats after suffering imidacloprid toxicity may decrease vocal-related FOXP2 expressions in the superior colliculus, auditory-related prestin expressions in the cochlea, and the auditory-related otoferlin expressions in the cochlea and the inferior colliculus, and cause inflammation and mitochondrial dysfunction-related apoptosis in the hippocampal CA1 and medial entorhinal cortex. These results may provide a reasonable explanation about imidacloprid-induced interference of echolocation system in insectivorous bats. 

Novel perspectives on bat insectivory highlight the value of this ecosystem service in farmland: Research frontiers and management implications. (Russo, D., Bosso, L. and Ancillotto, L. 2018) Bats are major consumers of arthropods, and there is ever growing evidence that they play a pivotal role in the fight against agricultural pests. However, relatively little research has addressed explicitly this important topic, and studies in temperate regions (especially European case studies) are infrequent. In the last few years, state-of-art molecular methods to identify prey remains in droppings and new experimental approaches to assess the actual magnitude of this ecosystem service have opened new perspectives in research. In this review, we discuss such aspects with an emphasis on temperate regions, and identify new research frontiers. These comprise: (1) detecting new bat species that consume pests, and further pest insects that bats might eat; (2) exploring sublethal effects of bat echolocation calls on tympanate moth pests; (3) getting a better understanding of bat predation over blood-sucking arthropods that parasitize livestock; (4) unveiling indirect effects of bat predation on plant pathogens; (5) implementing models to map the occurrence of bat insectivory and the potential to promote it; and (6) analyse bat droppings for active surveillance of arthropod pests and the diseases they carry. We also highlight that so-called “common” bat species, often neglected in conservation actions, are likely to provide the bulk of pest suppression in agroecosystems. All such aspects merit investigation and may lead to novel management practices aimed at conjugating bat conservation with economic and social sustainability of farming. 

Imidacloprid toxicity impairs spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. (Hsiao, C. et al. 2016) It has been reported that the decimation of honey bees was because of pesticides of imidacloprid. The imidacloprid is a wildly used neonicotinoid insecticide. However, whether imidacloprid toxicity interferes with the spatial memory of echolocation bats is still unclear. Thus, we compared the spatial memory of Formosan leaf-nosed bats, Hipposideros terasensis, before and after chronic treatment with a low dose of imidacloprid. We observed that stereotyped flight patterns of echolocation bats that received chronic imidacloprid treatment were quite different from their originally learned paths. We further found that neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas of echolocation bats that received imidacloprid treatment was significantly enhanced in comparison with echolocation bats that received sham treatment. Thus, we suggest that imidacloprid toxicity may interfere with the spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. The results provide direct evidence that pesticide toxicity causes a spatial memory disorder in echolocation bats. This implies that agricultural pesticides may pose severe threats to the survival of echolocation bats. 

Economic Importance of Bats in Agriculture. (Boyles, J. et al. 2011) White-nose syndrome (WNS) and the increased development of wind-power facilities are threatening populations of insectivorous bats in North America. Bats are voracious predators of nocturnal insects, including many crop and forest pests. We present here analyses suggesting that loss of bats in North America could lead to agricultural losses estimated at more than $3.7 billion/year. Urgent efforts are needed to educate the public and policy-makers about the ecological and economic importance of insectivorous bats and to provide practical conservation solutions.

Bat activity and species richness on organic and conventional farms: impact of agricultural intensification. (Wickramasinghe, L. et al. 2003) Agricultural intensification is perceived to be a major cause of the decline in many European bat populations. Because organic farming prohibits the use of agrochemicals, we compared organic vs. conventional farm types to test the hypothesis that agricultural intensification based on high levels of agrochemical use has been a factor in bat population declines. Bat activity and species richness were compared on matched pairs of organic and conventional farms. Bat activity was quantified using acoustic surveys within specific habitats on farms in southern England and Wales. Eighty-nine per cent of bat passes were identified to species level using artificial neural networks (ANN). A further 9% were identified to genus. Total bat activity was significantly higher on organic farms than on conventional farms. Significantly more bat passes were recorded over water on organic farms than on conventional farms. Foraging activity (quantified in two ways: total feedings buzzes and feeding buzzes per pass) was significantly higher on organic farms than on conventional farms. The dominant species on both farm types were Pipistrellus pipistrellus and Pipistrellus pygmaeus. Significantly more passes of Myotis species were recorded on organic farms than on conventional farms. This difference was also significant when water habitats were considered alone. The activity of both Myotis daubentonii and Myotis brandtii was significantly higher on organic farms than on conventional farms. The activity of Myotis bechsteinii and Myotis brandtii was significantly higher over organic water habitats than over conventional water habitats. Rhinolophus hipposideros and Rhinolophus ferrumequinum were only recorded on organic farms in wooded, arable and pasture habitats. Synthesis and applications. This study highlights the position of bats as bioindicators and victims of agricultural change. The differences in bat activity between farm types may reflect features such as taller hedgerows and better water quality on organic farms. Higher foraging activity also suggests that habitat quality in terms of prey availability is greater on organic farms. Less intensive farming benefits bats, and as the number of organic enterprises increases it may help to reverse declines in bat populations.