Ampulex
Don’t be fooled by the holiday finery of this wasp. It is dressed to kill but it’s not going out dancing. This splendid species of Ampulex (Family Ampulicidae) has more serious matters to attend to. All members of this genus are predators, and their choice of food is limited to one group of insects – the cockroaches. As do many aculeate wasps (those with a stinging apparatus) the female ampulicid (our image is actually of a male) digs out a prospective nest site and flies off to narcotize a cockroach by stinging it in the nervous system. Two stings are observed, the first into the prothoracic ganglion leads to short term (minutes) paralysis of the motor neurons. This leaves the prey helpless allowing a second sting to be administered into the cephalic ganglion (brain) inducing a longer lasting torpor (days), making it easier to drag or lead the unlucky roach back to the wasp’s nest. Once in the nest the female lays an egg or two between the roach’s legs. After hatching the larva chews its way into the abdomen of its prey, eventually consuming it. When mature, the larva pupates and undergoes metamorphosis, finally producing the adult wasp.
This address provides some very interesting information on ampulicid behaviour.
https://en.wikipedia.org/wiki/Emerald_cockroach_wasp
A note – the cockroaches (Blattoidea) are a very old and successful group (ca. 4500 species). Many are forest species and a very few are pests of humans. They have a bad rap. Until very recently it was thought that cockroaches first appeared in the fossil record ca. 300 million years ago (mya) (ie. a seriously old lineage). Recent revisionist work provides strong evidence that they are a much younger group, the first fossils of which are from about 130 mya. Old enough but not close to challenging the silverfish-like insects (that’s right, the little fellows who chew on your book bindings) that are dated to 390 mya. A further note of interest – it appears that the termites evolved from a roach ancestor.
Credits: Dr Robert Copeland