Introduction
When people think of pollinators, bees and butterflies are likely the first creatures that come to mind. In the Midwest, we are taught about these pollinators as key ecological regulators. That may be why we often forget about the other amazing pollinators of the world - such as bats! Like many of the most prominent pollinators on Earth, there are bats that live migratory lifestyles while others hibernate or do a bit of both. There are countless regions that benefit from the ecosystem services bats provide. Desert and Tropical regions are the most reliant on bat pollination, with the majority of the world's flower-pollinating bats being concentrated in Africa, Southeast Asia, and the Pacific Islands (1). Bats consume nectar from night-blooming flowers (2). Since a bat typically visits many plants in one feeding, it can carry lots of pollen on the fur of its face (3). A bat serves as a pollinator when it transfers pollen from one plant to another. Pollinating bats prefer large nectar-rich flowers with light color and a strong aroma (4). With their unique anatomy and lifestyles, bats fill a crucial niche in plant pollination. There are many plants that have co-evolved with bats and are dependent on them for survival, including over 300 fruiting species (4). Bats that serve as pollinators are often referred to as flying foxes or fruit bats. Unfortunately, bats are highly misunderstood creatures. If bats can do so much to support our ecology, economy, cultures, and food systems, then we can do more to protect and understand them, too!
Cultural Connections
PC: Penny Burke
Across the globe, a variety of cultures view and treat bats harshly. Superstition, legend, and misinformation about bats has caused various negative circumstances to persist over time. For example, the aforementioned fruit bats of the agave industry (which are harmless to humans) have their threatened status largely due to the fact that they are killed by humans who fear Vampire bats, which can be found in some of the same geographic areas (10). It is common for bats to be feared and admonished just for their supposed disease carrying potential. This idea came to a head particularly after the outbreak of COVID-19. According to lifetime bat researcher Merlin Tuttle, there is a long history of bats being unfairly blamed for disease outbreaks, and statistics about bat-human disease contraction being exaggerated (11). More and more research is beginning to challenge the outdated culture of bat-blaming. This data can bring people peace of mind knowing that the likelihood of contracting a disease from bats is extremely low (12). In fact, few people acknowledge the essential role bats play in pest and disease control. In many habitats, a single bat can catch and eat up to 1,000 mosquitoes in a single hour (13). When we imagine how many mosquitoes (which carry diseases like west nile and malaria) are suppressed by the population of bats that consume them, bats' role as disease controllers becomes obvious. Bats’ abilities to control insects is also largely undervalued in agricultural systems. Fortunately, there are some historical examples where the value of bats has been acknowledged. Before the rise of artificially produced fertilizers, bat excrement or guano had been utilized worldwide as fertilizer. This practice has been monumentally important in the historical evolution of agriculture. Guano fertilizer use can be traced to indigenous communities in South America; it is known for being heralded by Incan peoples. The traditional technique of guano application is a standout example of indigenous farming practices that have survived the test of time, colonial claims to globalize, and the threat of war (14). Another noteworthy example of bats being viewed in a positive way is in Chinese culture.The word Biānfú, meaning bat, sounds phonetically the same as words such as happiness, blessing, and good fortune (fú). Bats have been considered symbols of good luck in China for thousands of years (15).
At its core, the relationship between humans and bats exemplifies the way humans often disrespect the natural world - we shift blame and villainize the targeted beings, instead of taking accountability for our abundant ecological damages. For every negative encounter humans have with bats, the blame placed on the bat can most likely be reframed. It's probable that a person threatened the bats' security, be it physically or secondarily, where the actions of humanity at large caused the animal to be displaced or lacking essential resources. In order for these pollinators and ecosystem service providers to thrive, it is crucial for our understanding of bats to change, and for us to give credit where credit is due.
Pollinator’s Role in the Food System
Bats are pollinators for key food crops across the world. One key example relative to our part of the world is agave pollinating bats in the southern U.S., Mexico, and Central America. The entire agave industry is reliant on bats for pollination, pest control, and other ecosystem services. Agave is used for countless purposes, but the most common reasons for cultivation are for producing tequila, mezcal, and agave syrup. The three main bats that have a mutualistic relationship with agave are the Lesser long-nosed bat, the Greater long-nosed bat, and the Mexican long-tongued bat. In order to harvest the best agave, flower stalks (quiotes) are cut down (5). This is common practice in the industry, and is problematic to the bats, who rely on the flowers’ nectar for sustenance (5). The agave also serves as a site for reproduction and the sourcing of other foods. The deflowering of agave has been linked to the decline and threatened/endangered status of the three aforementioned species. In large scale farming, agave reproduction (in this case, planting) is not natural (i.e. facilitated by bats) and involves clones. Without genetic diversity of crops, the agave farms are faced with further ecological consequences, such as disease or parasitism (6). In Southeast Asia, bats are crucial in the pollination of durian. At present, durian exports and imports are at an all-time high, and the crop has been nicknamed “the king of fruits'' in Asia (7). Though the mutualistic relationship has been established for likely hundreds if not thousands of years, the pollination partnership between bats and durian trees has only been understood on a worldwide scale as of recently. The rising demand for durian agriculture has led to increased research on conditions that allow for successful fruit production. So it seems, mature trees are most capable of producing the best fruits, especially when the flowers are thoroughly doused in pollen (7, 8). As is the case in agave farming, the more the durian industry grows, the quality of the product and the landscape begin to decline. Research suggests that flying foxes (such as Pteropus and Acerodon genera) are more likely to pollinate wild growing durian, as opposed to trees in established plantations (8, 9). These bats, too, are threatened by the practices and demands of industrial-scale agriculture. Agave and durian are just two examples of globally traded and beloved food crops whose success relies on the aid of bats. Some other key food crops include bananas, mangoes, eucalyptus, figs, dates, guava, cashews, and yucca (4).
Sources Cited
“Bat Pollination”. U.S. Forest Service. https://www.fs.fed.us/wildflowers/pollinators/animals/bats.shtml#:~:text=Most%20flower%2Dvisiting%20bats%20are,Arizona%2C%20New%20Mexico%20and%20Texas.
Murphy, D. “Bats As Pollinators – An Introduction to Chiropterophily”. Awkwardbotany.com October 12, 2016. https://awkwardbotany.com/2016/10/12/bats-as-pollinators-an-introduction-to-chiropterophily/
“Bats Love to Pollinate”. Bat Conservation International. June 18, 2018. https://www.batcon.org/pollinator-week/
Dyer, M.H. “Bats As Pollinators: What Plants Do Bats Pollinate”. Gardenginknowhow.com. February 9, 2021. https://www.gardeningknowhow.com/garden-how-to/beneficial/bats-as-pollinators.htm
Garrone, M. “Capón”. From the Encyclopedia of Mezcal. Mezcalistas.com. March 25, 2020. https://www.mezcalistas.com/capon/
Hundt, L. “Variety is the Spice of Life”. Batconservationtrust.blogspot.com. May 22, 2012. http://batconservationtrust.blogspot.com/2012/05/variety-is-spice-of-life.html
“The True Cost Of Durian’s Explosive Growth”. Business Insider. Youtube. October 7, 2021. https://www.youtube.com/watch?v=5OHBqljDwjA
Chung, F. “Pollination of Durian Flowers”. Blogspot.com. http://durianinfo.blogspot.com/p/assisted-hand-cross-pollination-of.html
Hance, J. “World’s most controversial fruit may depend on giant bats for pollination”. The Guardian. February 19, 2018. https://www.theguardian.com/environment/radical-conservation/2018/feb/19/durian-flying-fox-bats-pollination-pollinators-deforestation-hunting-conservation
Medellín, R. “Leptonycteris yerbabuenae (Lesser Long-nosed Bat)”. International Union for Conservation of Nature (IUCN) Red List. 2016. https://www.iucnredlist.org/species/136659/21988965#assessment-information
“Exaggerated Disease Warnings”. Merlin Tuttle’s Bat Conservation. January, 2022. https://www.merlintuttle.org/resources/exaggerated-disease-warnings/
“Bats and human health”. Queensland Government. Health.qld.gov. August 27, 2020. http://conditions.health.qld.gov.au/HealthCondition/condition/14/217/14/bats-and-human-health#:~:text=What%20is%20the%20risk%20to,vaccinated%20should%20not%20handle%20bats
Tuttle, M. “Essential Bat Values”. Merlin Tuttle’s Bat Conservation. June 5, 2018. https://www.merlintuttle.org/resources/essential-bat-values/
“6. History shows guano is the organic fertilizer with the most mystique. ( And other Fun Facts)” Archipelagobatguano.com. 2007. http://archipelagobatguano.com/6.shtml
Kern, S.J. “Bats in Chinese Art”. Bat Conservation International. https://www.batcon.org/article/bats-in-chinese-art/