Doctoral Dissertations

Date of Award

5-1994

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Life Sciences

Major Professor

Gary F. McCracken

Committee Members

A. Echternact, J. Gittleman, S. Riechert, R. Strange

Abstract

The ecology of the fishing bat, Noctilio leporinus. was investigated on Culebra Island and Camuy, Puerto Rico. Diet, social organization, social behaviors, foraging, composition and use of pheromones were examined. Diet was assessed by analysis of guano and partially eaten prey found beneath roosts. The remains from small aerial insects, mostly beetles and moths, were present in guano in greater dry weight quantities than the remains of small fish, silversides (Atherinomorus stipes) and tilapia (Oreochromis aureus). Small quantities of other fish species, crabs, large insects, scorpions, and shrimp also were found. Noctilio leporinus is both an aerial insectivore and piscivore with a flexible foraging strategy that can adjust to local conditions and include terrestrial prey. Females roost in groups that remain together regardless of turnover in resident males and movements of the group to alternate roosts. Females remain associated with the same individuals and in the same location for several years. Resident males may retain their tenure for two or more reproductive seasons. Bachelor males roost solitarily or in small groups apart from females. Together, these characteristics appear to form the basis of a polygynous social organization. Roosts were not used as information centers as bats rarely followed each other from the roost to forage. Bats assembled into small groups outside of the roost, flew together to foraging areas, and used the same foraging sites repeatedly. At least some of the time, pairs of females foraged close enough to each other to communicate the location of prey. Only females from the same roost group foraged near to each other The distinctive odor of this species arises from oily secretions found beneath the wings in the subaxillary region. Females transfer the secretions from other group members to themselves by rubbing their head beneath other bats' wing. Secretions are also passed among group members when bats rubbed their foreheads together, possibly to develop a group-specific scent. Analysis of secretions identified 444 lipid compounds. As the secretions differ between sexes, information on sexual identity and reproductive condition may be communicated. Unique lipid compositions further suggest that bats may be individually recognizable by their odor.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS