Localization of prey by the Indian false vampire bat Megaderma lyra

Abstract

Studies on gleaning bats indicate that they do not mainly rely on echolocation to detect and capture prey from surfaces. In the event of not using echolocation, there may be an error in their passive localization of prey compared to the bats which use echolocation. It is to be tested whether the amount of such error is related with the size of the prey in the passive localization employed by gleaning bats. We conducted experiments on the Indian false vampire bat Megaderma lyra in an outdoor enclosure using small, medium and large-sized frogs as prey. M. lyra captured live and freshly killed frogs only when they jumped or when pulled with a long thread on a sandy floor. Bats were more successful in capturing frogs without error (i.e. landing straight on the frog) under the background of fluorescent light than red light. The number of captures of live frogs without error was also significantly higher compared to the captures of freshly killed frogs under both the lights, except with the large-sized frogs. The number of jumps made by the live frogs decreased with their body lengths increased before M. lyra captured them without error. In a few observations, instead of landing straight on the frogs the bats landed on the floor close to the frogs and then captured them in a short jump (i.e. localization made with an error). The distance between the final position of the frogs and the site at which the bats landed on the floor prior to the capture, is considered as the amount of error committed by bats. While the bats localized and captured the frogs with an error, we found a linear decrease of error with an increase in the body length of the frogs. Bats never responded to the movements of tiny live and dead frogs of 0.8-1.3 cm.Resume. -Les chauves-souris qui planent nc se servent generalcment pas de 1'echolocation pour detectcr et capturer des proies posees sur des surfaces. II peut done y avoir une crrcur de localisation de la proie. Cette erreur est-elle en rapport avec la taille de la proie ? Une experimentation a etc mcnee avec des faux vampires, ä Tinterieur et a I'exterieur d'une enceinte, et on a utilise comme proics des grenouilles de petite, moyenne ou grande taille. Cette chauve-souris capture des grenouilles vivantes qui sautent, ou des grenouillles fraichement tuces tirees par un long fil sur un sol sableux. Les chauves-souris capturaient avec plus de succes les grenouilles sous un cclairage fluorescent qu'en lumiere rouge. Le nombre de grenouilles vivantes capturees sans erreur a etc significativement plus eleve que le nombre des grenouilles fraichement tuees, quelle quc soit la lumiere, ä l'exception de celles de grande taille. Le nombre de sauts effectues par les grenouilles vivantes diminue tandis que leur taille augmente ct qu'elles sont capturees plus facilemcnt. La distance entre la position finale des grenouilles et le site d'atterrissage des chauves-sou- Mammatia, t. 63, n° 2,

Development of Prey Capture in the Indian False Vampire BatMegaderma Lyra

“…Adults of M. lyra usually roost and able to carry larger frogs (e.g. body length 5 cm) to ceiling at a height of 4 m in flight rooms (Marimuthu & Neuweiler 1987; Rajan & Marimuthu 1999; Ratcliffe et al. 2005).…”

“…The response was referred to bats flying down towards frogs, landing either straight on them or at a short distance away from them and flying back with or without capturing the frogs. Based on our direct observations, we measured the distance using a plastic scale between the place at which bats landed and the place where frogs stayed during such landings (Rajan & Marimuthu 1999). The number of jumps made by frogs and the number of attempts made by bats was noted for each successful capture in all observations.…”

“…landing closer to frogs and then captures with short jumps), when prey moves on sandy floors. This error decreases with increase in body lengths of frogs (Rajan & Marimuthu 1999). In this context, we hypothesized that (1) young bats could improve their hunting skills by trial and error, and that (2) the juveniles’ rate of prey consumption and method of handling prey progress with age.…”

“…It uses both prey‐generated noise (Marimuthu & Neuweiler 1987), echolocation (Schmidt et al. 2000) and possibly vision at closer range (Rajan & Marimuthu 1999) to localize prey on ground. Adult M. lyra captures frogs either without committing error (i.e.…”

Odor discrimination learning in the Indian greater short-nosed fruit bat (Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus

“…We captured male C. sphinx (n=12; forearm length 67±4 mm, body mass 51.6±9.0 g) using a mist-net (9×2 m; Avinet, Portland, ME, USA), in a guava orchard 2 km from the Bharathidasan University Campus, Tiruchirappalli, India (10°16′N, 78°15′E). We tagged these bats with plastic neck collars consisting of light-reflective coloured tapes, and recorded their morphometric details (Rajan and Marimuthu, 1999). We then kept the bats in an animal house facility in a free-flight chamber (2.2×1.3×2.1 m), under standard conditions (temperature 30±3°C, relative humidity 85±3% and 12 h:12 h light:dark cycle).…”