The influence of larval parasitism on life history strategies in water mites (Acari, Hydrachnidia)

Several life history traits in water mites known from different literature data are discussed. The following conclusions can be drawn: 1. Species with a parasitic larval phase can afford to produce small eggs with a low energetic value. 2. A substantial larval growth is achieved in species parasitic on water beetles or water bugs. In these water mites, adult size is strongly influenced by larval parasitism and the energetic gain allows a large egg production. 3. As a remnant of their evolutionary past, the parasitic larvae of most species have a terrestrial stage. It limits possible strategies in the life histories of water mites, as is shown for Eylais. 4. A high investment in maintenance by chemical defenses in combination with an extremely strong exoskeleton, or aggressive behaviour can lengthen the life span to two to three years.