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Cave-dwelling bats widely use anthropogenic structures such as temples in south Asia as roosting and nursery sites. Such roosts are constantly under threat, even more so after the COVID-19 pandemic. Despite the importance of such roosts, there is no detailed understanding of what makes temples favorable for bats and the critical factors for their persistence. Here we relate temple microhabitat characteristics and land use around ancient temples (>400 years) to bat species richness and abundance in the Tamiraparani river basin of south India. Temples were selected for sampling along the river basin based on logistics and permission to access them. We counted bats at the roost in the mornings and late afternoons from inside the temples. Temple characteristics such as dark rooms, walkways, crevices, towers, and disturbances to the roosts were recorded. Based on European Space Agency land use classifications, we recorded land use such as crops, trees, scrub, grassland, urban areas, and water availability within a 5 km radius of the temple. Generalized Linear Mixed Models were used to relate the counts in temples with microhabitats and land use. We sampled 59 temples repeatedly across 5 years which yielded a sample of 246 survey events. The total number of bats counted was 20,211, of which Hipposideros speoris was the most common (9,715), followed by Rousettus leschenaultii (5,306), Taphozous melanopogon (3,196), Megaderma lyra (1,497), Tadarida aegyptiaca (303), Pipistrellus sp . (144) and Rhinopoma hardwickii (50). About 39% of the total bats occurred in dark rooms and 51% along walkways. Species richness and total abundance were related to the availability of dark rooms and the number of buildings in the temple. Land use elements only had a weak effect, but scrub and grassland, even though they were few, are critical for bats. We conclude that retaining undisturbed dark rooms with small exits in temples and other dimly lit areas and having natural areas around temples are vital for bat conservation.

The traditional assumption that bats cannot synthesize vitamin C (Vc) has been challenged recently. We have previously shown that two Old World bat species (Rousettus leschenaultii and Hipposideros armiger) have functional L-gulonolactone oxidase (GULO), an enzyme that catalyzes the last step of Vc biosynthesis de novo. Given the uncertainties surrounding when and how bats lost GULO function, exploration of gene evolutionary patterns is needed. We therefore sequenced GULO genes from 16 bat species in 5 families, aiming to establish their evolutionary histories. In five cases we identified pseudogenes for the first time, including two cases in the genus Pteropus (P. pumilus and P. conspicillatus) and three in family Hipposideridae (Coelops frithi, Hipposideros speoris, and H. bicolor). Evolutionary analysis shows that the Pteropus clade has the highest ω ratio and has been subjected to relaxed selection for less than 3 million years. Purifying selection acting on the pseudogenized GULO genes of roundleaf bats (family Hipposideridae) suggests they have lost the ability to synthesize Vc recently. Limited mutations in the reconstructed GULO sequence of the ancestor of all bats contrasts with the many mutations in the ancestral sequence of recently emerged Pteropus bats. We identified at least five mutational steps that were then related to clade origination times. Together, our results suggest that bats lost the ability to biosynthesize vitamin C recently by exhibiting stepwise mutation patterns during GULO evolution that can ultimately lead to pseudogenization.

A total of 15 caves were explored between the year 2000 and 2001 in Western Ghats and other adjoining small hills of Tirunelveli and Madurai districts. Among 15 caves surveyed, eleven caves are located in Tirunelveli district and the remaining four caves are located in Madurai district. The length of surveyed caves are measured as 18.5, 16, 10.5, 65.6, 11 (right direction), 19 m (right direction), 17, 44.1, 8, 27, 29, 48.0, 69.5 m (right direction), 44.4 and 63.2 m, respectively from the entry. The height and the width of the caves varied extensively among them. Four different species of microchiropteran namely Hipposideros speoris, H. fulvus, Rhinopoma hardwickei and Megaderma lyra were occupied at different regions in caves. The bat R. hardwickei always seen at the crevice of entrance, while Hipposiderid bats occupied in well lit as well as in dark places from entrance to interior, whereas M. lyra always prefer to roost at dark zone of caves which is often inaccessible to most of the animals including human. Tineid moths and their maggots are predominantly seen on the faecal pellets of bats. [PUBLICATION ABSTRACT]

Although bats are nocturnal, many species emerge from roosts to forage during twilight, despite a presumed high risk of predation at this time. Here, we describe twilight foraging by a maternity colony of Schneider's leafnosed bat (Hipposideros speoris) in the dry zone of Sri Lanka and determine the dietary benefits of such behavior. Bats usually began foraging during dusk, sometimes before sunset, and also foraged during twilight in the morning. Mean use of available twilight by four radio-tagged bats was 75 percent. Twilight foraging made up, on average, 47 percent of the total foraging time of these bats (range = 25-96%), although twilight consisted of only 12 percent of the available time between sunset and sunrise the next morning. Eight species of potential predators (7 birds and 1 mammal) were observed within a 1 km radius of the colony, of which 5 species are predicted to regularly capture bats. Bats took a wide diversity of prey (11 insect orders, including at least 27 families, and spiders) that ranged in wing length from 2.0 to 54.0 mm. Major orders in the diet were Coleoptera, Lepidoptera, and Diptera. Prey of secondary importance included Hemiptera, Hymenoptera, Isoptera, and Neuroptera. Bats captured large numbers of insects that were only available or had marked peaks in abundance during twilight. These groups included small, swarming insects (especially flies) that have peaks in flight activity at dusk and dawn, large diurnal species (especially dragonflies) that have crepuscular activity, and winged termites that emerge in swarms at dusk. Access to these insects was a clear benefit of twilight foraging.

Although bats are nocturnal, many species emerge from roosts to forage during twilight, despite a presumed high risk of predation at this time. Here, we describe twilight foraging by a maternity colony of Schneider's leafnosed bat (Hipposideros speoris) in the dry zone of Sri Lanka and determine the dietary benefits of such behavior. Bats usually began foraging during dusk, sometimes before sunset, and also foraged during twilight in the morning. Mean use of available twilight by four radio-tagged bats was 75 percent. Twilight foraging made up, on average, 47 percent of the total foraging time of these bats (range = 25-96%), although twilight consisted of only 12 percent of the available time between sunset and sunrise the next morning. Eight species of potential predators (7 birds and 1 mammal) were observed within a 1 km radius of the colony, of which 5 species are predicted to regularly capture bats. Bats took a wide diversity of prey (11 insect orders, including at least 27 families, and spiders) that ranged in wing length from 2.0 to 54.0 mm. Major orders in the diet were Coleoptera, Lepidoptera, and Diptera. Prey of secondary importance included Hemiptera, Hymenoptera, Isoptera, and Neuroptera. Bats captured large numbers of insects that were only available or had marked peaks in abundance during twilight. These groups included small, swarming insects (especially flies) that have peaks in flight activity at dusk and dawn, large diurnal species (especially dragonflies) that have crepuscular activity, and winged termites that emerge in swarms at dusk. Access to these insects was a clear benefit of twilight foraging.

The Hipposideridae and Rhinolophidae are closely related families of bats that have similar echolocation (long-duration pure-tone signal, high duty cycle) and auditory systems (Doppler-shift compensation, auditory fovea). Rhinolophid bats are known to forage in highly cluttered areas where they capture fluttering insects, whereas the foraging habitat of hipposiderid bats is not well understood. Compared to rhinolophids, hipposiderid calls are shorter in duration, have lower duty cycles, and they exhibit only partial Doppler-shift compensation. These differences suggest that the foraging habit of the two families may also differ. We tested this hypothesis by studying foraging and echolocation of Hipposideros speoris at a site with a range of vegetation types. Bats foraged only while in flight and used all available closed and edge habitats, including areas adjacent to open space. Levels of clutter were high in forest and moderate in other foraging areas. Prey capture (n=42) occurred in edge vegetation where it bordered open space. Echolocation signals of H. speoris lacked an initial upward frequency-modulated sweep and were of moderate duration (5.1-8.7 ms). Sequences had high duty cycles (23-41%) and very high pulse repetition rates (22.8-60.6 Hz). Variation in signal parameters during search phase flight across foraging habitats was low. H. speoris showed a greater flexibility in its use of foraging habitat than is known for any rhinolophid species. Our study confirmed that there are differences in habitat use between hipposiderid and rhinolophid bats and we suggest that this divergence is a consequence of differences in their echolocation and auditory systems.

Although bats are nocturnal, many species emerge from roosts to forage during twilight, despite a presumed high risk of predation at this time. Here, we describe twilight foraging by a maternity colony of Schneider's leafnosed bat (Hipposideros speoris) in the dry zone of Sri Lanka and determine the dietary benefits of such behavior. Bats usually began foraging during dusk, sometimes before sunset, and also foraged during twilight in the morning. Mean use of available twilight by four radio‐tagged bats was 75 percent. Twilight foraging made up, on average, 47 percent of the total foraging time of these bats (range = 25–96%), although twilight consisted of only 12 percent of the available time between sunset and sunrise the next morning. Eight species of potential predators (7 birds and 1 mammal) were observed within a 1 km radius of the colony, of which 5 species are predicted to regularly capture bats. Bats took a wide diversity of prey (11 insect orders, including at least 27 families, and spiders) that ranged in wing length from 2.0 to 54.0 mm. Major orders in the diet were Coleoptera, Lepidoptera, and Diptera. Prey of secondary importance included Hemiptera, Hymenoptera, Isoptera, and Neuroptera. Bats captured large numbers of insects that were only available or had marked peaks in abundance during twilight. These groups included small, swarming insects (especially flies) that have peaks in flight activity at dusk and dawn, large diurnal species (especially dragonflies) that have crepuscular activity, and winged termites that emerge in swarms at dusk. Access to these insects was a clear benefit of twilight foraging.

Although bats are nocturnal, many species emerge from roosts to forage during twilight, despite a presumed high risk of predation at this time. Here, we describe twilight foraging by a maternity colony of Schneider's leafnosed bat (Hipposideros speoris) in the dry zone of Sri Lanka and determine the dietary benefits of such behavior. Bats usually began foraging during dusk, sometimes before sunset, and also foraged during twilight in the morning. Mean use of available twilight by four radio-tagged bats was 75 percent. Twilight foraging made up, on average, 47 percent of the total foraging time of these bats (range = 25–96%), although twilight consisted of only 12 percent of the available time between sunset and sunrise the next morning. Eight species of potential predators (7 birds and 1 mammal) were observed within a 1 km radius of the colony, of which 5 species are predicted to regularly capture bats. Bats took a wide diversity of prey (11 insect orders, including at least 27 families, and spiders) that ranged in wing length from 2.0 to 54.0 mm. Major orders in the diet were Coleoptera, Lepidoptera, and Diptera. Prey of secondary importance included Hemiptera, Hymenoptera, Isoptera, and Neuroptera. Bats captured large numbers of insects that were only available or had marked peaks in abundance during twilight. These groups included small, swarming insects (especially flies) that have peaks in flight activity at dusk and dawn, large diurnal species (especially dragonflies) that have crepuscular activity, and winged termites that emerge in swarms at dusk. Access to these insects was a clear benefit of twilight foraging.

Mother–young relations in a cave-dwelling microchiropteran bat colony of Hipposideros speoris were studied. Bats are altricial and mothers lavish meticulous care on their young. Most of the females leave their young inside the cave and some carry them to the foraging area. When they return after foraging, they retrieve their own young for suckling. Volant young exhibit 'practice flights' over short distances within the cave during the night. Experiments were carried out under both natural and seminatural environments to find out how a mother identifies her own young. Infants emit faintly audible vocalizations by which mothers are attracted; presumably, olfactory means also aid in final identification.

The emergence and returning activity patterns of a colony of microchiropteran bats Hipposideros speoris, under natural light-dark cycles keep pace with the timings of sunset and sunrise respectively. The onset of emergence flight occurred at different environmental twilight intensities which vary over the seasons. The seasonal changes of phase relationship between the onset and end of flight activity to sunset and sunrise respectively are discussed. As a result ψ-onset, ψ-end, and ψ-midpoint all undergo marked seasonal variations and the values obtained are well in accordance with the seasonal rule of Aschoff. The changes in the timings of onset and end of activity reflect the changes in the duration of activity time of the colony. The activity time is positively correlated with the duration of night time. The possible involvement of the 'non-parametric' action on the entrainment of this colony is briefly discussed.