Competitive growth, energy allocation, and host modification in the acanthocephalan Acanthocephalus dirus: field data
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The acanthocephalan Acanthocephalus dirus is a trophically transmitted parasite that modifies both the physiology and behavior of its intermediate host (isopod) prior to transmission to its definitive host (fish). Infected isopods often contain multiple A. dirus individuals and we examined the relationships between host sharing, body size, energy content, and host modification to determine if host sharing was costly and if these costs could influence the modification of host behavior (mating behavior). Using field-based measures of parasite energy content (glycogen, lipid) and parasite body size (volume), we showed that host sharing was costly in terms of energy content but not in terms of body size. Analysis of the predictors of host behavior revealed that energy content, and body size, were not predictors of host behavior. Of the variables examined, parasite intensity was the only predictor of host behavior. Hosts that contained more parasites were less likely to be modified (i.e., less likely to undergo mating suppression). We suggest that intraspecific competition influenced parasite energy content and that the costs associated with competition are likely to shape the strategy of growth and energy allocation adopted by the parasites. These costs did not appear to have a direct effect on the modification of host mating behavior.
KeywordsCaecidotea intermedius Mating suppression Glycogen Lipid Body size
Funding was provided by DePaul University through the Paid Leave Program (University Research Council), a Competitive Research Grant (University Research Council), a Faculty Summer Research Grant (College of Science and Health), the Undergraduate Research Assistantship Program, the Undergraduate Summer Research Program and the Department of Biological Sciences. Amit Raj and Sarah Blackstock assisted in the field.
Compliance with ethical standards
The study was performed in compliance with national laws and regulations.
Conflict of interest
The authors declare that they have no conflict of interest.
- Brattey J (1980) Preliminary observations on larval Acanthocephalus lucii (Müller, 1776) (Acanthocephala: Echinorhynchidae) in the isopod Asellus aquaticus (L.). Parasitology 81: xlix-1.Google Scholar
- Crompton DWT (1970) An ecological approach to acanthocephalan physiology. Cambridge University Press, CambridgeGoogle Scholar
- Moore J (2002) Parasites and the behavior of animals. Oxford University Press, OxfordGoogle Scholar
- Poulin R (2007) Evolutionary ecology of parasites, 2nd edn. Princeton University Press, New JerseyGoogle Scholar
- Poulin R, Morand S (2000) Testes size, body size and male-male competition in acanthocephalan parasites. J Zool (Lond) 250:551–558Google Scholar
- Sánchez MI, Rode NO, Flaven E, Redón S, Amat F, Vasileva GP, Lenormand T (2012) Differential susceptibility to parasites of invasive and native species of Artemia living in sympatry: consequences for the invasion of A. franciscana in the Mediterranean region. Biol Invasions 14:1819–1829CrossRefGoogle Scholar