Great Black Digger Wasp

• Its provisioning routine is so rigid that it has become a classic case in philosophy and cognitive science: if an experimenter moves the cricket a few centimetres while the wasp is inspecting the nest, she drags it back to the entrance and repeats the inspection from the start, over and over again.
• The sting does not kill the cricket: it paralyses it, so that the prey stays fresh until the larva has finished eating it.
• It is a solitary wasp and very unaggressive towards people, despite its imposing size.
• The female hunts crickets, paralyses them with a precise sting and drags them to a burrow she has dug, where she lays an egg on each one. The prey remain alive, motionless, until the larva devours them.
• The adult eats no meat: it feeds on nectar. Hunting is solely for the brood.
• This genus starred in a classic experiment in the philosophy of mind. The wasp leaves her prey at the nest entrance, goes in to inspect, then brings it inside. If an observer moves the prey a few centimetres while she is inside, on coming out she puts it back at the entrance and repeats the inspection, over and over, dozens of times in a row.
• From this, Douglas Hofstadter coined the term sphexishness, to describe behaviour that looks deliberate but is a rigid programme incapable of adapting.
• Later studies have qualified the experiment: not all wasps fall into the loop indefinitely, and some end up altering the routine.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat & environment

Meadows, gardens and roadsides of eastern North America

Sources consulted: Fabre, Souvenirs entomologiques; Wooldridge, The Machinery of the Brain; Keijzer (2013), Biology and Philosophy

Best time: July to September, on the flowers of umbellifers and mint