Behavioral Ecology Advance Access originally published online on July 10, 2009
Behavioral Ecology 2009 20(5):1020-1025; doi:10.1093/beheco/arp092
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Effect of parasite-induced behavioral alterations on juvenile development
a GEMI/UMR CNRS-IRD 2724, Equipe: Evolution des Systèmes Symbiotiques, IRD, 911 Avenue Agropolis, B.P. 5045, 34032 Montpellier Cedex 1, France b School of Biological Sciences, Heydon Laurence Building A08, University of Sydney, Sydney, New South Wales 2006, Australia c Zoologisches Institut, Evolutionsbiologie, Universität Basel, Vesalgasse 1, CH-4051 Basel, Switzerland d Génétique et Dynamique des Populations, Centre d'Ecologie Fonctionnelle et Evolutive, CNRS–UMR 5175, 1919 route de Mende, 34293 Montpellier Cedex 5, France e Institut des Sciences de l'Evolution, Université Montpellier 2—CNRS, Case Postal 65, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France f Department of Biology, Moscow State University, Moscow 119899, Russia g Institut de la Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke East, Montréal, Québec, LX2B2 Canada
Address correspondence to F. Ponton. E-mail: fleur_ponton{at}hotmail.com.
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Abstract |
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Like many trophically transmitted parasites, the trematode Microphallus papillorobustus alters the behavior of its intermediate host, the crustacean gammarid Gammarus insensibilis, in a way that favors its vulnerability to definitive hosts (aquatic birds). Parasitized females still produce eggs, but because juvenile development occurs inside the female marsupial brood pouch, young gammarids are subject to the same risk of predation as their mothers until they exit the marsupium. We explored the idea that developing juveniles can adjust their developmental schedule in a state-dependent manner according to the parasitic status of the mother. We predicted that juveniles from parasitized females would accelerate their development, or exit the marsupium at an earlier stage, to avoid predation by birds. Contrary to our expectations, we observed the opposite, that is, juveniles from parasitized females exited the marsupial brood pouch significantly later than those from uninfected mothers. We discuss these results in relation to current ideas on host manipulation by parasites in ecosystems.
Key words: amphipod, developmental schedule, manipulative parasite, maternal effect, predation, trematode.
Fleur Ponton and David Duneau contributed equally to this work.
Received 13 November 2008; revised 19 May 2009; accepted 4 June 2009.