Cotesia congregata

A hornworm rears up when attacked by a parasitic Cotesia congregata wasp. The wasp injects not only her eggs, but a specialized virus that disables the caterpillar's immune system. Laboratory animals at the University of Illinois.

Cotesia congregata

A parasitic braconid wasp oviposits into a laboratory-reared hornworm. The host insect receives not just eggs, but a polydnavirus encoded in the wasps genome that disables the animal's immune system. University of Illinois, USA.

Cotesia larvae spinning cocoons

Having emerged from their dying host caterpillar, parasitic Cotesia larvae spin silken cocoons to protect themselves as they mature into adult wasps. Urbana, Illinois, USA.

Cotesia wasp cocoons

Cocoons of the parasitoid wasp Cotesia line the back of a tomato hornworm. The caterpillar is, unfortunately, still alive. Urbana, Illinois, USA

Cotesia wasp cocoons

Cocoons of the parasitoid wasp Cotesia line the back of a tomato hornworm. The caterpillar is still alive, though sluggish. Urbana, Illinois, USA

Megischus bicolor

Silhouetted against the dusk sky, a parasitic wasp lays her egg in the dead trunk of a redbud tree. Her target is probably wood-boring beetles. Urbana, Illinois, USA.

Microgastrinae

The remains of a caterpillar, covered in the vacated silked cocoons of the tiny wasps that killed it. Yarra Ranges National Park, Victoria, Australia.

Megischus bicolor

A female crown-of-thorns wasp, in the relatively uncommon family Stephanidaem, oviposits into a beetle burrow. Urbana, Illinois, USA.

Telenomus sp.

An egg-parasitioid wasp (Platygastridae: Scelioninae) lays her eggs into an egg of a Caligo owl butterfly. Cayó District, Belize.

Hippodamia sp. with parasitoid cocoon

A ladybird beetle, weak but alive, stands guard above the pupa of a parasitic wasp that has emerged from its body. The ability of parasites to selfishly manipulate their victims' behavior is a fascinating and poorly understand aspect of their biology. Hastings Reserve, California, USA.

Rhipiphorus

A female Rhipiphorus sp. wedge-shaped beetle lays an egg in an aster. These odd insects are parasites of bee larvae. On hatching, the young beetle grub will attempt to hitch a ride back to a bee's nest where it will attack the bee's own offspring. Shawnee National Forest, Illinois, USA

Dasymutilla occidentalis

Velvet ants are not true ants, but solitary wasps that parasitize soil-nesting bees and wasps. Sand Ridge State Forest, Illinois, USA.

Monacon sp.

The perilampid wasp Monacon is a parasitoid of platypodine ambrosia beetles. Kibale Forest, Uganda. (Thanks to Chris Darling for the ID)

Comperia merceti

Comperia merceti (Encyrtidae) is only a couple millimeters long, but it has an outsized effect on cockroaches. Young wasps of this species develop inside cockroaches’ hardened egg cases, consuming the eggs. Like the vast majority of wasps, Comperia is not aggressive and does not sting. Laboratory colony at the University of Arizona.

Copidosoma sp.

All that remains of this looper caterpillar is its barest curled shape. The body has been replaced by thousands of wasp grubs that divided and divided from a single egg laid by the Copidosoma wasp's mother. Austin, Texas, USA.

Copidosoma sp.

A vial fills with adult wasps as they emerge from a parasitized looper caterpillar. Austin, Texas, USA.

Evania appendigaster

Portrait of the cockroach parasite Evania appendigaster. The abdomen of this wasp is so small that at first glance it appears to be missing. Cairns, Queensland, Australia.

Xorides sp.

A parasitic wasp drills into dead wood on a living redbud tree to lay an egg. Her target is likely a wood-boring beetle or horntail larva. Urbana, Illinois, USA.

Mesostenus gracilis

Portrait of a parastic wasp. The family Ichneumonidae is among the most species rich of all animal families. Austin, Texas, USA.

Orasema sp.

An ant-parasite wasp (Eucharitidae) lays an egg in a Heliconius leaf. The young hatchling will attempt to hitchhike on a passing ant into the nest, where it will prey on developing larvae. Ibagué, Tolima, Colombia

Idiolispa aestivalis

Portrait of a parasitic wasp. Austin, Texas, USA.

Ichneumon wasp

The ubiquitous parasitoid wasp family Ichneumonidae presents a nearly limitless array of colors, shapes, and sizes. Refugio Amazonas, Tambopata, Peru.

Lytopylus (Braconidae: Agathidinae)

A female wasp oviposits into a sunflower. These insects are parasites of seed-feeding moths. Lake Forest, Illinois, USA

Microgastrinae

A small braconid wasp delicately threads her ovipositor into a dead tree branch to reach her target. Urbana, Illinois, USA.

Doryctes

Portrait of one of North America's largest braconid wasps. Austin, Texas, USA.

Doryctes

Portrait of one of the largest North American braconid wasps. Austin, Texas, USA

Leptopilina boulardi

Leptopilina boulardi (Figitidae) is a parasitoid wasp that attacks the larvae of drosophilid fruit flies. Here, a female probes a rotting banana with her ovipositor.