Authors: H Hawlena Z Abramsky B R Krasnov
Publish Date: 2005/07/16
Volume: 146, Issue: 2, Pages: 200-208
Abstract
Parasites often confront conflicting demands when evaluating and distributing themselves among host individuals in order to attain maximum reproductive success We tested two alternative hypotheses about host preference by fleas in relation to the age of their rodent host The first hypothesis suggests that fleas select adult over juvenile rodents because the latter represent a better nutritional resource the “wellfed host” hypothesis whereas the second hypothesis suggests that fleas prefer the weaker and less resistant juveniles because they are easier to colonise and exploit “poorly fed host” hypothesis We sampled fleas Synosternus cleopatrae on the gerbil Gerbillus andersoni in 23 different plots in the Negev desert and found an unequal distribution of fleas between adult and juvenile hosts Furthermore flea distribution changed as a function of flea density—from juvenilebiased flea parasitism the “poorly fed host” hypothesis at low densities to adultbiased flea parasitism the “wellfed host” hypothesis at high densities Other factors that influenced flea preference were soil temperature and the presence of ticks These results suggest that host selection is not an explicit alternative choice between adults and juveniles “wellfed host” versus “poorly fed host” hypotheses but rather a continuum where the distribution between adults and juveniles depends on host parasite and environmentally related factorsGeorgy Shenbrot Amos Bouskila Ofer Ovadia Burt Kotler Jonathan Belmaker Victor China and Uri Roll were involved in interesting discussions We thank Nadezhda Burdelova BenGurion University of the Negev Israel Maria Stanukovich and Dmitry Apanaskevich both from Zoological Institute of the Russian Academy of Sciences for their help in ectoparasite identification We are grateful to Nivi Kessler Mariela Liederman Arnon Tsairi and Dudi Greenbaum for their invaluable help with all aspects of the study We also appreciate the thoughtful comments of Jennie McLaren on an earlier version of the manuscript We thank Lajos Rozsa and two anonymous referees for their helpful comments Financial support during this study was provided by Ministry of Science Culture and Sport of Israel grant 011800331 This is publication no 186 of the Ramon Science Center and no 490 of the Mitrani Department of Desert Ecology
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