Better hosts dive:: Detachment of ectoparasitic water mites (Hydrachnellae: Arrenuridae) from damselflies (Odonata: Coenagrionidae)

Water mire larvae parasitizing damselflies must detach while the host is in a suitable reproduction habitat for both parasites and itself They should do so during the host's oviposition. In this paper I present experimental data for the detachment rate of water mite larvae (Arrenurus cuspidator) from different host species, Coenagrion hastulatum and C. puella, in relation to the host's oviposition behavior. C. hastulatum oviposits submerged, whereas C. puella oviposits at the water surface and aggregates with conspecifics. It was found that mite larvae detach at a significantly higher ratio from hosts with submerged oviposition. Experimental tests showed that this is nor a species-specific effect. It is caused mainly by the oviposition behavior. The results are discussed in the light of different oviposition systems in damselflies.