 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 inconspicuous. When the wasp larva hatches it begins to feed on the still-living spider. After consuming the edible parts of the spider, the larva spins a silk cocoon and pupates – usually emerging as an adult the next summer. Some species lay the egg on a still-active spider, where it feeds externally on hemolymph (spider blood). In time, that spider will die, and the mature wasp larva will then pupate.
They usually hunt on ground with the characteristic wing flicking movement. The tarantula hawk is only one of a number of related species of wasps that mainly parasitize spiders and in entomological terms are referred to as parasitoids. They typically hunt out their prey, sting and paralyzed them and carry them back to their nest. The nest is typically a hole in the ground into which they insert one or more spiders upon which they subsequently lay a single egg. After hatching the wasp larva feed on the paralyzed prey until completing development.
Tarantula Hawk-Pepsis spp. This is a species of spider wasp which hunts tarantulas as food for it larvae. Up to two inches long with a blue-black body and bright rust-colored wings, tarantula hawks are among the largest of wasps. The coloring on their wings warns potential predators that they are dangerous (Aposematism). Their long legs have hooked claws for grappling with their victims. The stinger of a female tarantula hawk can be up to 1/3 inch long, and delivers a sting which is rated among the most painful in the insect world.
During the spiders’ reproductive season male tarantulas are usually emaciated from ignoring food while searching for females. The tarantula hawks thus prefer female tarantulas and seek them in their burrows. The females capture, sting, and paralyze the spider, Then they either drag the spider back into her own burrow or transport their prey to a specially prepared nest where a single egg is deposited on the spider’s body, and the entrance is covered. The wasp larva, upon hatching, begins to suck the juices from the still-living spider. After the larva grows a bit, it plunges into the spider's body and feeds voraciously, avoiding vital organs for as long as possible to keep it fresh. After completing pupation the adult wasp emerges from the nest. Tarantula wasps feed primarily on nectar and other natural sugary materials. The consumption of fermented fruit sometimes intoxicates them to the point that flight becomes difficult. While the wasps tend to be most active in daytime summer months, they avoid the very highest temperatures. The male tarantula hawk does not hunt; instead, it feeds off the flowers of milkweeds, western soapberry trees, or mesquite trees. The male tarantula hawk has a behavior called "hill-topping", where he sits atop tall plants and watches for females that are ready to reproduce.
Tarantula Hawk Dragging Prey to Nest and Feeding on Milkweed Nectar. Image Courtesy of Astrobradley (left) and Davehood (right).
The tarantula hawk is relatively docile and rarely stings without provocation. The sting, particularly of Pepsis formosa, is am