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Title:The ethology of the Malayan false vampire bat (Megaderma spasma), with special emphasis on auditory cues used in foraging
Author(s):Tyrell, Karen
Doctoral Committee Chair(s):Salmon, Michael
Department / Program:Biology, General
Biology, Ecology
Biology, Zoology
Agriculture, Forestry and Wildlife
Discipline:Biology, General
Biology, Ecology
Biology, Zoology
Agriculture, Forestry and Wildlife
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, General
Biology, Ecology
Biology, Zoology
Agriculture, Forestry and Wildlife
Abstract:My laboratory studies have revealed the use of two distinct foraging strategies by the echolocating Malayan false vampire bat, Megaderma spasma. When gleaning, bats retrieve prey located upon surfaces. Because both the prey and the surface reflect sound, bats may have difficulty distinguishing echo distortions caused by relatively small prey from sound reflected off of the larger substratum. In contrast, flycatching bats capture flying prey mid-air, where background clutter is minimal. Because these foraging environments impose different restrictions on the use of sensory cues by hunting bats, a primary focus of my work was to determine what cues are used by foraging M. spasma, and their role in generating adaptive behavioral responses.
Because the behavior of this bat is poorly known, I developed an ethogram to use as a basis for subsequent behavioral investigations. Behavior described includes potential communicative vocalizations, and patterns of agonistic and non-agonistic, non-vocal social behavior. Non-social (individual) behavior described includes maintenance behavior, ingestive and eliminative behavior, and resting postures. Behavior patterns were placed into tentative functional groupings and compared to the behavior of other bat species.
The use of acoustic cues in prey capture by M. spasma depends upon the foraging strategy employed. Passive listening to prey-generated sounds is critical for the capture of prey by gleaning M. spasma. Passive auditory cues were used both to detect prey and to determine its angular (elevation and azimuth) coordinates. In the absence of such cues, echolocation was not used to locate prey itself. However, gleaning bats always emitted echolocation pulses, which may serve to determine the distance to the substratum surface. In contrast to surface gleaning, in the absence of prey-generated sounds flycatching bats use echolocation to locate prey and to assess prey physical features. However, when such sounds are available, bats use them to make qualitative assessments about prey. These results suggest that bats use different acoustic cues to optimize the detection, localization, and identification of prey under constraints imposed by different foraging situations. Periodic abundance of different prey types which results from seasonal climatic changes may be important in shaping the foraging behavior of M. spasma.
Issue Date:1990
Rights Information:Copyright 1990 Tyrell, Karen
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9026338
OCLC Identifier:(UMI)AAI9026338

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