19
Nov
Climate Change Threat to Ecosystem Management of Insects Focus of New Book
(Beyond Pesticides, November 19, 2025) In the book, Biological Control Systems and Climate Change, published this month, Danilo Russo, PhD—a speaker during the first session of our 42nd National Forum, The Pesticide Threat to Environmental Health: Advancing Holistic Solutions Aligned with Nature—and other researchers add to the existing literature on the climate change threat to ecosystem services. Dr. Russo’s chapter, entitled “Impact of Climate Change on Bats Involved in Biological Control,†explains one of the lost benefits of ecological balance attributable to the climate crisis.
As explained in the book: “In conservation biological control, habitats surrounding and within crops are managed to favour an increase in natural enemy populations while suppressing pest populations. These agroecological systems can be complex, and are affected by climate change.†The ability of climate change to influence the effectiveness of biological control systems is explored, showing the “effects on the large diversity of macro- and microorganisms involved in biocontrol, and the possible increase or decrease in pest outbreaks following changes in characteristics (morphology, physiology, behaviour….), distribution or phenology.â€
Dr. Russo is a full professor of ecology at the University of Naples Federico II, an international leader in bat research, and coauthor of A Natural History of Bat Foraging: Evolution, Physiology, Ecology, Behavior, and Conservation. Dr. Russo’s interests include habitat selection, resource partitioning, sensory ecology, social behavior, evolutionary biology, biogeography, and invasion ecology. Much of his research focuses on bats, but he also works on a range of other model organisms to answer the specific questions related to ecosystem services. Dr. Russo has published over 200 scientific articles in internationally respected journals, including Nature Communications, Current Biology, Ecology Letters, and Biological Reviews. He has conducted fieldwork in diverse regions and environments across the globe, from African rainforests to Israeli deserts and European beech forests. (See more about Dr. Russo here, as well as the recording of his talk during the National Forum here.)
As Dr. Russo states in previous research: “The ongoing biodiversity crisis highlights the need for targeted conservation efforts, yet the focus often remains on rare and endangered species. This overlooks the vital role of common species, which are the ecological backbone of ecosystems, supporting the stability and functioning of biodiversity. We argue that common species, especially their population dynamics and potential tipping points, are too often neglected and that their conservation is urgent. We illustrate this issue using bats (Chiroptera) as a model. This diverse mammalian order features key ecosystem service providers, including insectivores, pollinators, and seed dispersers. Bats are sensitive to anthropogenic pressures, and many species, including common ones, face population declines and the impact of ecosystem disruption.â€
The Important Role of Bats and Impacts of Climate Change
The new book, the second in the CABI Ecostacking Series, informs students, researchers, lecturers, and stakeholders engaged in biological control worldwide on the impacts of climate change. Biological control (referred to as “biocontrolâ€) in agriculture is described as the use of natural enemies (predators, parasitoids, or pathogens) for the management of pests in crops.
In the chapter by Dr. Russo et al., bats are highlighted for their “indispensable role in agricultural systems worldwide, serving as natural enemies of arthropod pests and significantly reducing the use of pesticides.†The ability to benefit from the natural predation provided by bats as an alternative to pesticides helps protect biodiversity, soil health, and human health, while also mitigating the impacts of climate change.
Petrochemical pesticides contribute to climate change throughout their entire lifecycle, from manufacturing, application, and disposal, by releasing greenhouse gases like carbon dioxide, methane, and nitrous oxide, and by creating a “vicious cycle” as climate change leads to increased pesticide use. About 99% of synthetic pesticides are derived from fossil fuels, and their production is an energy-intensive process that releases greenhouse gases. Not only can pesticide manufacturing release significant amounts of carbon dioxide, but synthetic nitrogen fertilizer applications used in combination with pesticides increase the production of nitrous oxide, a potent greenhouse gas, in soils. Soil degradation is another concern, as pesticides can negatively impact soil health, hindering its ability to sequester carbon.
As Dr. Russo points out, “Climate change can disrupt predator–prey interactions in agricultural systems by altering species’ physiology, distribution and behaviour,†including deleterious impacts on bat populations. Changes to temperatures and precipitation can destabilize the dynamics of existing resources, which can “reduce natural pest control effectiveness, increasing reliance on chemical methods.†Research, outlined below, shows that climate change impacts bat distribution, reproduction, behavior, and survival through heat stress and drought, among other factors.
Shifts in weather patterns that occur as a result of climate change “disrupt bat–pest interactions, creating mismatches between pest outbreaks and bat presence,†the authors state. They continue, “Climate change also affects insect emergence and bat reproduction timing, potentially leading to pest outbreaks.†Growth rates, reproductive cycles, and the habitat ranges of both predators (bats) and prey (insects) are impacted by alterations in temperature and precipitation patterns, which complicate the stability of ecological interactions and can cause cascading effects throughout the ecosystem.
The researchers share: “Climate-induced changes in prey vulnerability due to changes in body condition or habitat significantly influence predator responses. For instance, changes in the prey’s body condition might make the prey vulnerable to predation… Climate change also alters species distribution, leading to potential mismatches between predators and prey. Mathematical models predict that global warming and wind flow can affect prey and predator populations, potentially leading to instability in predator–prey interactions. Specifically, changes in prey distribution due to warming are predicted to disrupt established interactions with potential implications for ecosystem stability.â€
These impacts alter population dynamics and thus alter the effectiveness of biological pest control and farmland productivity. “This process can result in increased pest populations and reduced crop yields in agricultural systems,†the authors note. “For instance, if predators do not adjust their breeding times to match the peak abundance of their prey, their effectiveness in controlling pest populations may be compromised, leading to increased reliance on chemical pest control methods.â€
While these effects of climate change on predator–prey interactions are not exclusive to bats and insects, bats are particularly sensitive creatures. The proportions of their wings and tail to their small bodies leave them prone to dehydration, their position in the food web requires stability, and their low reproductive output makes them particularly vulnerable to population impacts, with very slow recovery. These factors cause bats to be sensitive to extreme events, such as heatwaves, droughts, wildfires, and storms.
Ecosystem Services of Bats
As cited on Beyond Pesticides’ Benefits of Bats page, as well as in Dr. Russo’s research, there are more than 1,400 species of bats worldwide, with over 40 species in the U.S. alone, and they make up 25% of the world’s total mammal population. Dr. Russo et al. write: “Bats’ diverse hunting strategies, which target various insect pest species, make them remarkably versatile and effective in pest suppression across many crop types, from rice and corn to fruit orchards and cotton plantations… This wide variety of feeding strategies makes bats crucial providers of ecosystem services such as regulation of arthropod populations.â€
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. Over 500 plants worldwide are completely or partially dependent on bat pollination. Seed dispersal is another important service bats provide.
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. 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 crops. These bats “employ different hunting strategies depending on their foraging guilds.†As Dr. Russo states: “Some are specialized in capturing flying insects (aerial-hawking bats), while others seize prey directly from foliage or the ground (gleaning bats), and some skim it from the water surface (trawling bats). These varied hunting strategies make bats versatile and effective predators in different environments and on a wide variety of prey.â€
Previous Research
Within the chapter, the researchers cite evidence that shows the impacts of climate change on bats, with implications not only for bat and insect populations, but the economy, overall biodiversity, agricultural productivity, and human health.
This includes:
- In the U.S., droughts are associated “with up to 50% reduction in reproductive output of several Myotis bat species.†(See study here.)
- Estimations for fringed myotis bats (Myotis thysanodes) show population decreases of up to 90% across the range of the species under future climate change scenarios due to reduced reproductive rates.
- Growing evidence suggests that climate change may be causing bats to give birth earlier in the season. (See research here, here, here, and here.)
- “Unstable weather conditions may also reduce bat pup survival, further diminishing the population of pest predators.†(See here and here.)
- Bats “provide substantial economic benefits across a wide range of crops, including cereals such as rice or corn, fruit trees like vineyards and apple orchards, oil palm plantations, plantations of coffee or sugarcane, and non-food crops such as cotton or rubber trees.â€
Previous coverage from Daily News highlights the threats from pesticides and climate change that cascade from bat population impacts to infant mortality. Earlier research demonstrates the decline of bat populations in the USA resulting from the spread of white-nose syndrome (WNS), a lethal fungal disease caused by Pseudogymnoascus destructans. This mortality, due to the loss of ecosystem services that bats provide as natural predators, leads to dramatic increases in pesticide use. A 2024 study finds that as a result of these implications, a corresponding rise in infant mortality also occurs. (See Daily News here.)
Farmers rely on bats as alternatives to pesticides to protect their crops from insects, but WNS has greatly impacted bat populations since 2006. With the collapse of many bat populations in counties in North America, these farmers turn to toxic chemicals to replace the ecosystem services bats usually provide. These chemicals, however, endanger human health.
The Benefits of Organic and Additional Resources
As Dr. Russo et al. summarize: “Numerous studies highlight the ecological importance of bats in agroecosystems, emphasizing their ability to reduce crop damage and yield loss. This, in turn, decreases the need for agrochemical pesticide application, which not only reduces costs for farmers but also mitigates the negative impacts of these chemicals on ecosystems and human health. Ultimately, by lowering pest levels and promoting more sustainable farming practices, bats contribute to the long-term viability of agricultural systems and save substantial amounts of money for farmers and land managers, reinforcing their crucial role in the farming economy.â€
The path forward to protect beneficial organisms such as bats, along with all wildlife, the environment, and human health, is organic land management. Organic practices provide health and environmental benefits while combating current crises of biodiversity and climate change. (See Daily News Bats in Organic Agriculture: Precision Foraging as Pest Management for more information.) Â
“As invaluable allies in sustainable farming practices, bats globally contribute to the natural balance of agroecosystems,†Dr. Russo concludes. “Therefore, the conservation of bat populations is paramount for preserving the stability, health and resilience of agricultural environments world-wide, which, in parallel, enhances long-term food production.â€
Help support Beyond Pesticides’ mission of transitioning to a world free from toxic pesticides by becoming a member today. Learn more about the impacts of pesticides on health with the Pesticide-Induced Diseases Database and safer alternatives here and here.
Join us for the SECOND session of the National Forum on December 4, 1 – 3:30 Eastern! Featuring Carolina Panis, PhD, Jabeen Taiba, PhD, and Emile Habimana, M.S. in a compelling discussion that elevates public understanding on the scientific data linking petrochemical pesticides to the crisis in breast cancer, pediatric cancer, and sewage sludge (biosolids) fertilizer—supporting the imperative for ecological land management.
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All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Russo, D. et al. (2025) ‘Impact of Climate Change on Bats Involved in Biological Control’, in Biological Control Systems and Climate Change. CABI Ecostacking Series, pp. 104–116. Available at: https://www.cabidigitallibrary.org/doi/10.1079/9781800625099.0008.
