a1 Génetique et Evolution des Maladies Infectieuses (CNRS-IRD UMR 2724), 911 Avenue Agropolis, Montpellier 34394, France
a2 Department of Evolutionary Ecology, Consejo Superior de Investigaciones Científicas (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain
Parasitic infection is often associated with changes in host life-history traits, such as host development. Many of these life-history changes are ultimately thought to be the result of a depletion or reallocation of the host's resources driven either by the host (to minimize the effects of infection) or by the parasite (to maximize its growth rate). In this paper we investigate the energetic budget of Aedes aegypti mosquito larvae infected by Vavraia culicis, a microsporidian parasite that transmits horizontally between larvae, and which has been previously shown to reduce the probability of pupation of its host. Our results show that infected larvae have significantly less lipids, sugars and glycogen than uninfected larvae. These differences in resources were not due to differences in larval energy intake (feeding rate) or expenditure (metabolic rate). We conclude that the lower energetic resources of infected mosquitoes are the result of the high metabolic demands that microsporidian parasites impose on their hosts. Given the fitness advantages for the parasite of maintaining the host in a larval stage, we discuss whether resource depletion may also be a parasite mechanism to prevent the pupation of the larvae and thus maximize its own transmission.
(Received November 30 2006)
(Revised January 29 2007)
(Accepted February 19 2007)
(Online publication July 18 2007)
c1 Corresponding author: Génetique et Evolution des Maladies Infectieuses (CNRS-IRD UMR 2724), 911 Avenue Agropolis, Montpellier 34394, France. Tel: +34 914 111 328. Fax: +34 915 645 078. E-mail: email@example.com
p1 Current address: Department of Biology, Queen's University, ON K7L 3N6 Kingston, Canada.