Many parasites are transmitted trophically, whereas others can either succumb to, or escape from, the predators of their hosts. We examined the extent to which larval arrenurid water mites (Arrenurus planus Marshall, 1908 and Arrenurus pollictus Marshall, 1910) parasitizing lestid damselflies (Lestes forcipatus Rambur, 1842 and Lestes disjunctus Sélys, 1862) escape from predatory libellulid dragonflies that are consuming their hosts. We hypothesized that the brightly coloured mites would be avoided by feeding dragonflies. However, all partially engorged A. pollictus mites were eaten while their host was being consumed in staged predation trials. In contrast, half of the fully engorged mites detached and therefore escaped consumption. Trials with A. planus mites showed that they detached more readily than their congenerics, which may be due to selection on those temporary pond mites to survive desiccation stress following detachment. The effect of dragonfly predation on transitioning of mites from parasitic larvae to their free-living aquatic stages therefore depends on the degree of engorgement and the mite species.
Canadian Journal of Zoology
Department of Biology

Nagel, L., Zanuttig, M., & Forbes, M. (2011). Escape of parasitic water mites from dragonfly predators attacking their damselfly hosts. Canadian Journal of Zoology, 89(3), 213–218. doi:10.1139/Z10-112