Life history of two new species of Prorops (Hymenoptera, Bethylidae) ectoparasitic on adult Hypothenemus eruditus beetles (Curculionidae, Scolytinae) in Hawai‘i

Aspects of the life history and biology of two Prorops spp. are explored, Prorops maya sp. nov. and Prorops umiehu sp. nov. Aspects of their behavior are deduced through dissection of plant material and through the use of “phloem sandwich” style observation chambers. Both were found to be ectoparasitoids of adult Hypothenemus eruditus beetles. They thus show a novel feeding behavior as, along with a Plastanoxus sp., the only bethylids known to parasitize the adult stage of their hosts, and the only known ectoparasitoids of adult scolytids. Searching, stinging, host feeding, and oviposition behaviors are reported and illustrated with photographs and video. Oviposition occurs on the ventral side of the membraneous region between the pro- and mesothorax of the beetle, and larvae feed through this location. The projection on the frons, a defining character of the genus Prorops , is observed to function as a tongue and groove mechanism with which the adult female pushes on the edge of the prothoracic sclerite of the host beetle while maintaining use of its mandibles to chew on the membrane underneath for host feeding and in preparation for oviposition. Defensive action of a Hypothenemus sp. against the wasp's sting by clamping down on the intruding ovipositor between its pro- and mesothorax is also reported, though this behavior was only observed once and thus its generality is uncertain.