Behavioral Ecology and Sociobiology

, Volume 37, Issue 5, pp 321–328

Echolocation call design and limits on prey size: a case study using the aerial-hawking bat Nyctalus leisleri

  • Dean A. Waters
  • Jens Rydell
  • Gareth Jones
Article

DOI: 10.1007/BF00174136

Cite this article as:
Waters, D.A., Rydell, J. & Jones, G. Behav Ecol Sociobiol (1995) 37: 321. doi:10.1007/BF00174136

Abstract

The echolocation calls used by Nyctalus leisleri during search phase in open air space are between 9 and 14 ms long, with the peak energy between 24 and 28 kHz. The pulses are shallowly frequency-modulated with or without an initial steep frequency-modulated component. The diet consists primarily of small flies (Diptera), including many chironomids (wingspan 9–12 mm) and yellow dung flies (Scatophaga; wingspan 24 mm), but also of some larger insects such as dung beetles (Coleoptera; Scarabaeoidea), caddis-flies (Trichoptera) and moths (Lepidoptera). The echo target strength of some prey items was measured. Contrary to models based on standard targets such as spheres or disks, the echo strength of real insects was found to be virtually independent of the emitted frequency within the 20–100 kHz frequency range. A model was used to calculate probable detection distances of the prey by the bat. Using narrow-band calls of 13.7 ± 2.7 ms duration, a bat would detect the two smallest size classes of insect at greatest range using calls of 20 kHz. The results may therefore explain why many species of large and medium sized aerial-hawking bats use low-frequency calls and still eat mostly relatively small insects. The data and model challenges the assumption that small prey are unavailable to bats using low-frequency calls.

Key words

BatEcholocationFeeding ecologyUltrasoundTarget strength

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Dean A. Waters
    • 1
  • Jens Rydell
    • 2
  • Gareth Jones
    • 1
  1. 1.School of Biological SciencesUniversity of BristolBristolUK
  2. 2.Department of ZoologyUniversity of AberdeenAberdeenUK
  3. 3.Department of ZoomorphologyUniversity of GothenburgGothenburgSweden