Fruit bat-people interactions: benefits, costs, or risks?Submitted by editor on 20 April 2022.Get the paper!
Photo 1: Day roost of The Indian Flying Fox
Forbidden fruits? Ecosystem services from seed dispersal by fruit bats in the context of latent zoonotic risk
Bats can be effective seed dispersers of many forest trees and fruit crops, in human-modified landscapes. Bats scatter seeds widely by dropping them or defecating them during flights, and aggregate or clump seeds under feeding trees or night roosts (perching sites) or day roosts. These processes of frugivory and seed dispersal by bats may turn into benefits or even costs for people sharing resources with them, depending on how people factor them into fruit production.
Through our interdisciplinary research in India’s Western Ghats, we found that people track bat-dispersed seeds and collect them for use, with a realization of significant economic value from the process of seed dispersal. But benefits of bat seed dispersal may be accompanied with costs of fruit damage or loss due to bats, so not all is positive in the narrative of seed dispersal benefits. We therefore examined how perceptions of people varied across regions. Overall, across different contexts of fruit production, bats were perceived to be more beneficial due to clumped seed dispersal of commercially important crops such as cashew and areca, than harmful due to damage or loss to pulpy fruits like banana or guava, which also matched with our field measurements.
Photos 2A: Cashew nut collector, and 2B: collection bucket with bat-bitten cashew-apples & attached seeds
Apart from socio-economic benefits/costs, bats are also now increasingly known to harbour viruses that can cause disease risks to people through direct or indirect contact with bats. In fruit plantations, of say cashew, there can be contact while accessing the fruits or seeds dropped by bats which may have bat secretions. Through compilation of spatial data on risk factors for disease transmission from fruit bats (from field observations and secondary data), we assessed how disease risks correlated with net benefits from bats in our study area. We found that, interestingly, areas where perceptions of benefits were high were areas with lower likelihood of zoonotic risk.
Photo 3: Infographic depicting benefits, costs and risks from fruit bats to people in fruit plantations
Our paper, through ecological studies of fruit bats, interviews with plantation-associated people, and disease risk assessments, highlights socio-economic benefits from clump dispersal by fruit bats, while being cognizant of some costs and disease risks from bats. To our knowledge, this is one of the first studies to explicitly link bat seed dispersal ecology with social perceptions and disease risks. Our insights can inform emerging frameworks for interdisciplinary studies on human-bat interactions across the tropics. As zoonotic diseases increasingly become central to human well-being, we emphasize on balanced assessments of bat-linked ecosystem services and risks, to identify effective conservation strategies. Our results suggest a hopeful scenario for both bat conservation and human well-being.
All photos and infographic by Kadambari Deshpande