Naturwissenschaften

, Volume 95, Issue 6, pp 561–567

Ethanol concentration in food and body condition affect foraging behavior in Egyptian fruit bats (Rousettus aegyptiacus)

Authors

    • Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert ResearchBen-Gurion University of the Negev
  • Carmi Korine
    • Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert ResearchBen-Gurion University of the Negev
  • Burt P. Kotler
    • Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert ResearchBen-Gurion University of the Negev
  • Berry Pinshow
    • Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert ResearchBen-Gurion University of the Negev
Original Paper

DOI: 10.1007/s00114-008-0359-y

Cite this article as:
Sánchez, F., Korine, C., Kotler, B.P. et al. Naturwissenschaften (2008) 95: 561. doi:10.1007/s00114-008-0359-y

Abstract

Ethanol occurs in fleshy fruit as a result of sugar fermentation by both microorganisms and the plant itself; its concentration [EtOH] increases as fruit ripens. At low concentrations, ethanol is a nutrient, whereas at high concentrations, it is toxic. We hypothesized that the effects of ethanol on the foraging behavior of frugivorous vertebrates depend on its concentration in food and the body condition of the forager. We predicted that ethanol stimulates food consumption when its concentration is similar to that found in ripe fruit, whereas [EtOH] below or above that of ripe fruit has either no effect, or else deters foragers, respectively. Moreover, we expected that the amount of food ingested on a particular day of feeding influences the toxic effects of ethanol on a forager, and consequently shapes its feeding decisions on the following day. We therefore predicted that for a food-restricted forager, ethanol-rich food is of lower value than ethanol-free food. We used Egyptian fruit bats (Rousettus aegyptiacus) as a model to test our hypotheses, and found that ethanol did not increase the value of food for the bats. High [EtOH] reduced the value of food for well-fed bats. However, for food-restricted bats, there was no difference between the value of ethanol-rich and ethanol-free food. Thus, microorganisms, via their production of ethanol, may affect the patterns of feeding of seed-dispersing frugivores. However, these patterns could be modified by the body condition of the animals because they might trade-off the costs of intoxication against the value of nutrients acquired.

Keywords

ChiropteraFood selectionGiving-up densityState-dependent foragingToxins

Copyright information

© Springer-Verlag 2008