roughout the United States and Canada; the same habitat where their hosts are most diverse.
Spider Wasps. These are one of the better know groups of large Hymenoptera. Most of the Spider Warps are orange and black, black and grey/white markings or just black, i.e., the very strong warning colors. They usually have tinted wings, smooth and shiny body. Their hind-legs are long and always have two prominent spurs. They tend to coil their antennae. Spider wasps are best distinguished from other similar wasps in having (in most species) a transverse groove dividing the mesopleuron (the mesepisternal sclerite, a region on the side of middle segment of the thorax above the point where the legs join) into halves.
Spider Wasp with Coiled Antennae and Mesoplural Transverse Groove Dividing Segment above Attachment of Second Pair of Legs
In South America spider wasp species may be referred to colloquially as marabunta or marimbondo, though these names can be generally applied to any very large stinging wasps). The family is cosmopolitan, with some 4,200 species in 4 subfamilies. All species are solitary, and most capture and paralyze prey, although some species are cleptoparasites of other pompilids, or ectoparasitoids of living spiders. Sexual dimorphism is not marked although females are often larger than the males.
Spider wasps are long-legged, solitary wasps that use a single spider as a host for feeding their larvae. They paralyze the spider with a venomous stinger. Once paralyzed, the spider is dragged to where a nest will be built – some wasps having already made a nest. A single egg is laid on the abdomen of the spider, and the nest – or burrow – is closed.
Spider Wasps Collecting Prey. Images Courtewy Tony Willis.
The size of the host can influence whether the wasp will lay an egg that will develop as a male, or an egg that will develop into a female – larger prey yielding the (larger) females. A complex set of adult behavior can then occur, such as spreading dirt or inspecting the area, leaving the nest site incons