Infection of army ant pupae by two new parasitoid mites (Mesostigmata: Uropodina)

Abstract

A great variety of parasites and parasitoids exploit ant societies. Among them are the Mesostigmata mites, a particularly common and diverse group of ant-associated arthropods. While parasitism is ubiquitous in Mesostigmata, parasitoidism has only been described in the genusMacrodinychus. Yet information about the basic biology of mostMacrodinychusspecies is lacking. Out of 24 formally described species, information about basic life-history traits is only available for three species. Here we formally describe two newMacrodinychusspecies, i.e.Macrodinychus hilpertaeandMacrodinychus derbyensis. In both species, immature stages developed as ecto-parasitoids on ant pupae of the South-East Asian army antLeptogenys distinguenda. By piercing the developing ant with their chelicera, the mites apparently suck ant hemolymph, ultimately killing host individuals. We compare infection rates among all studiedMacrodinychusspecies and discuss possible host countermeasures against parasitoidism. The cryptic lifestyle of living inside ant nests has certainly hampered the scientific discovery ofMacrodinychusmites and we expect that many more macrodinychid species await scientific discovery and description.