Question: Are mite dispersion on damselfly hosts, host flight distance, and host resistance related to engorgement size of ectoparasitic larval mites? Hypothesis: Adaptation to temporary ponds explains why larvae of some mite species engorge to larger sizes, which translates into high costs of parasitism and greater expression of resistance in their hosts. Organisms: Two species of lestid damselflies and two species of arrenurid water mites. Field sites: A temporary pond and a permanent marsh in eastern Ontario, Canada. Methods: We recorded mite prevalence and intensity, and scored spacing of larval mites on newly emerged damselflies and eventual engorgement sizes of mites on mature damselflies from each site. We then estimated the total minimum volume of extracted resources taken by engorged mites of both species. We also measured host flight distance, as well as the magnitude of immune resistance to mites. Conclusions: Mites from the temporary pond engorged to larger sizes and were more widely spaced than larvae of another mite species from the permanent pond. The total minimum volume of digested host tissues extracted was larger for temporary pond mites, despite them averaging fewer mites per host than the other mite species. Damselflies parasitized by these larger mites were more affected by parasitism based on flight distances. Resistance to these mites occurred more frequently than resistance to mites of the species that engorged much less.

Additional Metadata
Keywords Costs of parasitism, Parasite engorgement, Pond permanence, Resistance
Journal Evolutionary Ecology Research
Nagel, L., Zanuttig, M., & Forbes, M. (2010). Selection on mite engorgement size affects mite spacing, host damselfly flight, and host resistance. Evolutionary Ecology Research, 12(5), 653–665.