European Mantispid

Mantispa styriaca — the European mantispid — is one of about 400 species in family Mantispidae (the mantispids — small predatory neuropteran insects characterized by mantis-mimic body morphology) and the European cousin of the NA mantispid (already in the Wild Files). The species is widespread across temperate Europe (especially southern and central Europe — the species is restricted to areas with abundant wolf spider hosts for larval development). Adults are 1-2 cm body length, with the species' diagnostic features that make the species one of the most-cited examples of CONVERGENT EVOLUTION in modern biology: RAPTORIAL FRONT LEGS (highly modified for prey capture, with serrated tibial edges that fold against femoral edges to grip prey — looking exactly like the raptorial front legs of a praying mantis); TRIANGULAR HEAD with prominent forward-facing eyes (similar to mantis head morphology); MANTIS-LIKE BODY POSTURE; and four membranous wings (the wings differ from mantis wings — mantispids have membranous neuropteran wings rather than the leathery wing covers of mantises). The species belongs to the INSECT ORDER NEUROPTERA (the lacewings, antlions, owlflies) — entirely separate from the order Mantodea (the praying mantises). Mantispids and mantises are NOT CLOSELY RELATED — they are in different insect orders, and their similar body morphology is one of the most-cited examples of CONVERGENT EVOLUTION (independent evolution of similar body forms in unrelated lineages, driven by similar selective pressures — both groups are predatory ambush hunters that benefit from the raptorial-front-legs-and-triangular-head morphology). The species is also famous for the LARVAL OBLIGATE PARASITISM OF SPIDER EGG SACS. First-instar mantispid larvae are tiny (1-2 mm), actively-mobile, and BEHAVIORALLY SPECIALIZED to ACTIVELY SEARCH OUT SPIDER EGG SACS in the environment. The larva uses sensory cues (including spider silk, spider pheromones, and spider egg sac chemistry) to LOCATE A SPIDER EGG SAC of compatible host spider species (especially wolf spiders Lycosidae and other ground-dwelling spiders that produce egg sacs in the larva's habitat). Once an egg sac is located, the larva BURROWS INSIDE the egg sac and BEGINS CONSUMING THE DEVELOPING SPIDER EGGS AND SPIDERLINGS — completing larval development on the contained spider eggs over 4-6 weeks, then pupating INSIDE THE EGG SAC, and emerging as an adult mantispid by chewing through the egg sac wall. The egg-sac-parasitism life cycle is one of the most extraordinary cases of OBLIGATE LARVAL PARASITISM in modern entomology and is featured in essentially every modern textbook discussion of mantispid biology and convergent evolution. The species is harmless to humans and is a flagship subject of European arthropod biology.