Leschenault’s rousette, or fulvous fruit bats, in Sikkim on March 29, 2019. Photo: Dibyendu Ash/Wikimedia Commons, CC BY-SA 4.0.
Bats have recently been in the news for all the wrong reasons. They were associated with the COVID-19 outbreak early on, as the reservoirs of the novel coronavirus in the wild, but that only led to the spread of misinformation and animosity against bats everywhere. The forcible removal of bats from many places and destruction of bat habitats have been reported. At the same time, environmentalists and public health experts have issued messages dissuading such vandalism and describing the importance of protecting bats.
Bats provide key ecosystem services for human wellbeing, including pest control, pollination and seed dispersal, but they are considered pests, reservoirs of disease and sites of unhygienic practices that need to be erased from the floral landscape. In India, only two species, out of some 120, fall within Schedule 1 of the Wildlife Protection Act 1972: the Salim Ali fruit bat and the Wroughten’s free-tailed bat.
Bats are typically remarkably tolerant to disturbance caused by human activities, but more recent events indicate otherwise. The authors studied studied bats in the temples in Tenkasi, Tirunelveli and Thoothukudi districts of Tamil Nadu from 2012 to 2017. In the tropics, especially in South Asia, several species of insectivorous and frugivorous (fruit-eating) bats use temples, pagodas, churches and large trees to roost in the day and as nursing sites. There are many micro-habitats within the tower, many dark corners, crevices, spires, etc.; different species stratify based on the microhabitat available.
These structures are peppered around India, and have thus been one of the mainstays of many species of bats for centuries. We don’t know exactly how many bats are there but estimates run into the millions. As a result, when many of these temples are modernised, the process destroys bat roosts and their nurseries, thus threatening their population in the area.
In South Tamil Nadu, we found 47 of the 58 temples we surveyed to have bats – between 2,922 and 5,116 of them. There were six species – six insectivorous and one frugivorous. The most common species was Schneider’s leaf-nosed bat (Hipposideros speoris), accounting for nearly half the population, while the lesser mouse-tailed bat (Rhinopoma hardwickii) was the rarest.
These bats’ principal threats are large-scale disturbances such as renovation activities and deliberate trapping and removal. In 2018, a Leschenault’s rousette (Rousettus leschenaulti) was killed and hung from a coconut tree near the Srivaikundam Perumal temple in Thoothukudi district to scare other bats away.
However, if some areas are relatively undisturbed during renovation, the bats move there temporarily and return to their original sites after the disturbance has reduced. In Gangaikondan, some 20 km north of Tirunelveli, a few abandoned rooms in a temple housed a large population of the black-bearded tomb bat (Taphozous melanopogon) and the greater false vampire bat (Megaderma lyra) while the more active parts of the temple were being renovated over two years. Such abandoned rooms appear to be the major drivers of bats’ presence in temples. There is certainly a strong correlation between the presence of bats and the availability of unused rooms.
However, when renovation activities become too intense, the bats do desert the temple altogether. In one abandoned temple, there were over 10,000 Leschenault’s rousettes in the 1990s, but since then the temple was refurbished and painted anew and today there no bats of this species in the area. Between 2012 and 2018, we found that bats have lost about 9% of their roosting sites by no longer being able to access temples in Tenkasi, Tirunelveli and Thoothukudi. Some species seem to prefer temples and old buildings, so as temples are ‘upgraded’, we also threaten the lives of these species.
For example, in the last nine years, large colonies of Leschenault’s rousettes in Nanguneri temple, Veeravanallur Boominathar temple and near the Bramadesam temple have completely abandoned their roosts. Until 2014, there had been over 1,300 bats, but in 2018 we recorded only 27.
Why we need temple bats
Bats play important roles role in forest ecosystems as well as in agricultural areas, and many rural settlements are often ordered around local temples. Bats feed on a variety of insects, including many pests. A study published in 2014 found that bats that preyed on planthoppers, a major rice pest, could have saved 2,900 tonnes of paddy in a year in Thailand, worth $1.2 million and enough to feed 26,000 people for a year. A recent study along similar lines isn’t available for India, but in 1986, M.R.G.K. Nair wrote that dusky leaf-nosed bats (Hipposideros ater), an insectivorous species near Tirunelveli, are voracious consumers of red flour beetles, a major pest of stored grains. Fruit bats are also well-known pollinators and help disperse the seeds of plants of the Madhuca, Syzygium and Ficus genera.
Bats occupy temples if they can’t find comparable alternatives like caves. And caves have become harder to find in this area thanks to extensive quarrying, while urbanisation and real-estate development has put paid to old buildings. Irrational fears stoked by people during the ongoing pandemic has only further legitimised bat clearance activities, often in a brutal manner that serves no purpose other than to put ourselves at a disadvantage.
There is no direct link between bats and COVID-19 in humans. Bats don’t directly transmit any viruses to humans; there needs to be an intermediate host species. Some studies have suggested pangolins could have been the go-between for the novel coronavirus but this is beside the point.
Recent reports from Tirunelveli district, as from other parts of India, say local officials have been felling trees where bats have been spotted nursing their young ones. Once the lockdown is lifted, temples are also likely to be fumigated and the bats entirely driven away instead of being temporarily relocated. It’s important to maintain clean surfaces but considering the novel coronavirus’s modes of transmission, excessive precaution like power-washing a spire many metres above ground won’t help.
It would also be worthwhile to remember we share our spaces with many other lifeforms, and our needs don’t automatically assume importance over the needs of these creatures.
T. Ganesh is a senior fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru. A. Saravanan and M. Mathivanan are research associates in ATREE’s Agasthyamalai Community Conservation Centre, Manimutharu, Tirunelveli, Tamil Nadu.