Montana Public Radio

Bug Bytes: Giant Ichneumon Wasps

Jun 16, 2020

Learning to identify different wasp species can be challenging, but it’s not brain surgery.

Well…actually, in this case it just might be.

We’re talking about giant ichneumon wasps – a genus of only four species in North America. Females range from 3-4 inches in length, including what appears to be a long, massive stinger. While intimidating looking, they’re harmless. This stinger is actually an ovipositor, used for laying eggs.

Credit Glenn Marangelo

The ovipositor of giant ichneumon wasps is incredibly long for a good reason. They have a big job ahead when laying an egg. Like many wasps, they’re parasitic, laying eggs onto another living animal for their offspring to eventually consume. In this case, the specific host is the larvae of wood or horntail wasps, located up to two inches under the surface of a tree.

Using her sensitive antennae, the female wasp feels for vibrations indicating that a host larva is present. Then the work begins. She’ll raise her long abdomen into the air, trying to position her ovipositor directly above the larva. She’ll then begin to drill.

Her ovipositor has two blades that work together -- one drills while the other holds the bit in place. The blades then switch roles with the shaft that drilled taking hold while the other cuts deeper. An incredibly effective drilling process leaving behind the smallest of holes.

What can we learn from this?

Inspired by the giant ichneumon wasp’s ovipositor, researchers have developed a flexible, steerable needle that can take the least invasive route to deposit cancer treatments, or skirt around parts of the brain where a larger incision could do lasting damage.