Hemipepsis heros – Tarantula Hawk wasp

Tarantula Hawk wasp

This is one of 180 species of wasp known as tarantula hawks. They are so named as they hunt tarantulas and other large spiders. However, the adults don’t eat these spiders themselves. Instead they carry their quarry back to a burrow. The paralysed spider has an egg laid on its skin and is walled up inside its tomb. The paralysed tarantula survives for about 35 days as a living food source for the developing wasp grub. The grub hatches and rapidly grows by drinking the fluids from the spider’s abdomen. By the fourth moult, the grub is able to burrow through the spider’s carapace and begin eating the internal organs of the spider. This eventually kills the spider, and the grub continues to feast until only a hollow shell remains. The grub leaves the body and pupates in the burrow. It eventually emerges as an adult wasp and excavates its way out of the tomb.

Eyes: Hemipepsis wasps, like all insects, have compound eyes made up of hundreds of individual lenses. This is unlike the single lens eyes seen in higher organisms such as vertebrates. The multiple lenses build up one complete image of the view around the wasp.

Wings: The venation patterns on the wings are the only way to visually separate Hemipepsis wasps from their close relatives the Pepsis wasps. Hemipepsis heros, like most tarantula hawks, have aposematic coloration. This contrasting colouration of glossy dark wings with lighter coloured legs and body markings warns predators that they have powerful defences in their sting. The colouration is shared by both males and females, with the males benefitting from the warning despite having no sting.

Mouth: Adult wasps feed exclusively on the nectar of flowers. Their mouthparts are adapted to drink from the opening of flowers. In South Africa alone, Hemipepsis wasps are the sole pollinators of 18 different plant species, and across the world many plants have evolved alongside these wasps.

Armour: Hemipepsis wasps are some of the most well-armoured insects. Their smooth armour plates allow them to avoid being pinned by tarantulas during battle. The thick armour stops the spider from penetrating with its fangs on the rare occasions they do pin the wasps down. One study showed only a single injury to wasps and no wasp deaths in over 200 recorded encounters.

Legs: The long powerful legs of these wasps, gives them the leverage to drag their heavy prey to a burrow in order to lay their eggs upon the paralysed body of the tarantula. The legs also have defensive spines, which aid in its defence when attacking a spider

Sting: Within the tail of the wasp is its sting. This sting delivers a toxin so painful it is only surpassed by the bullet ant in pain rankings. This toxin is the result of balanced evolutionary pressures, creating a toxin that is strong enough to deter the most persistent vertebrate predators without reaching lethal levels that would kill its tarantula hosts. The venom is just strong enough to permanently paralyse a host tarantula to allow the developing wasp grub to feed on the living spider.