Program Sponsored by: Ecohealth Alliance

Bats

Photo by Andrew Spalton

Bats constitute one of the most successful radiations in mammalian biodiversity, comprising the second-largest mammalian order with an estimated 1,400+ documented species (Simmons and Cirranello, 2019).

Ecological & economic services provided by bats

Bats provide vital ecological and economic services, most notably pollination of fruit crops, forest regeneration through seed dispersal, suppression of insect pests that damage crops and vector human diseases, and primary suppliers of nutrients (guano) in cave ecosystems (Kunz et al., 2011). Fruit-eating bats (family Pteropodidae) are the primary pollinators and seed dispersers for approximately 300 plant species, from which numerous economically valuable products are produced (Fujita and Tuttle, 1991). Lesser dawn bats (Eonycteris spelaea), a nectarivorous bat species native to Southeast Asia, is the primary pollinator of durian (Bumrungsri et al., 2009), which generates revenues exceeding $1.5 billion annually in Southeast Asia. Insectivorous bat species are the primary predators of nocturnal insects, including numerous costly agricultural pest species, thereby serving as natural pest control agents. Leelapaibul et al. (2005) estimated that a colony of 2.6 million wrinkle-lipped free-tailed bats (Chaerephon plicatus) could consume at least 17.5 tons of insects on a nightly basis. Furthermore, the insects consumed by this particular species were the primary pests of local rice crops (Leelapaibul et al., 2005). Guano produced by large aggregations of roosting bats support entire communities of invertebrates that rely upon this nutrient-rich food source.

Threats to bats

Tragically, human pressures on bat populations are manifold, with the rapid land conversion from urban encroachment and agricultural intensification contributing to rapid declines in bat populations globally (Mickleburgh et al., 2002). Human pressures are magnified further by overexploitation through unregulated hunting for consumption, inclusion in medicinal remedies (e.g., asthma) (Mildenstein et al., 2016), sport (Epstein et al., 2009), and the souvenir trade (Lee et al., 2015). In addition to these relatively widespread threats to bats, regional threats also exist that can lead to the indirect killing of bats or persecution and disturbance of roosting bats. In Western Asia, widespread application of pesticides to control crop pests, including spraying in caves and abandoned buildings occupied by bats (Amr et al., 2006; Alagaili, 2008), and agricultural intensification, which has led to the establishment of irrigation systems that deplete available water in this largely arid region (Alagaili, 2008), have contributed to declines in regional bat populations. A more recent and unique threat to bats in Western Asia is the fraudulent scheme of selling “bat nests” on Facebook and other social media platforms, with sellers claiming the “nests” contain “red mercury” that has healing properties (Zohoori, 2018). There are no documented cases of bats building nests (Kunz, 1982), yet the perceived notion that bats create such economically valuable structures has likely led to increased cave disturbance, potentially displacing or indirectly killing roosting bats (Zohoori, 2018). This fraud is speculated to have originated in Iran but has quickly grown in popularity in Jordan (Khanfar, 2018) and Turkey, Azerbaijan, and Iraq (Zohoori, 2018).