Baeus Wasps: these strange little wasps are smaller than a grain of sand, and the females are flightless
Wasps of the genus Baeus are sometimes described as "micro-flea wasps," because the females of this genus have tiny, rounded bodies that measure just 0.8mm long.
Above: a female Baeus wasp compared to the tip of a pencil
Baeus represents one of the most unusual genera of parasitic wasps in that females are apparently wingless, highly compact and flea-like in appearance. They are endoparasitoids of spider eggs of host families associated with above-ground vegetation and crytobiotic niches such as leaf-litter.
Above: female Baeus wasps
The wasps often ride around on the backs of female spiders, simply waiting to parasitize the spiders' eggs:
They have a hypodermic-like ovipositor that is used to pierce the chorion of a host egg, in which they lay their own egg. The [wasp] larva then consumes the contents of the host egg, pupates within it, and emerges as a fully developed adult.
Above: a female Baeus wasp clinging to the underside of a cellar spider's eggsac
This genus remains poorly studied, with only 25 species currently described world-wide:
Even though the highly unusual nature of Baeus has been known for over 170 years, only 25 species have been described to date, three from Australia, seven from the Nearctic, six each from the Neotropics and the Palaearctic, one each from the Oriental and Afrotropical (Seychelles) regions, and one from Hawaii. However, significant numbers of species occur in many regions, particularly in the wet tropics, subtropics and southern hemisphere temperate forests.
Above: a Baeus wasp depicted next to a 0.7mm mechanical pencil lead
These may be the world's most adorable wasps.
Above: a female Baeus wasp grooming herself
