Aulacid wasp
The vibrating antennae were actually tapping the wood, a form of vibrational sounding or echo location¹. This is where the enlarged tibia come in, as these have been shown to be capable of sensing the vibration of the returning echoes².
The female ichneumon’s vibrating antennae are testing for the hollow passages in the wood where grubs are burrowing. Once she locates a grub, she pierces the wood with her ovipositor, and then places an egg on, in or near the grub. When the egg hatches, the larva will begin to feed on the grub, eventually killing it. The ichneumon larva will then pupate and eventually emerge from the wooden passage.
Darwin, when considering the claims of a beneficient intelligent designer, used the ichneumon as one example of why he could not believe this:
“But I own that I cannot see, as plainly as others do, & as I shd wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedlyin created the Ichneumonidæ with the y express intention of their feeding within the living bodies of caterpillars, or that tcat should play with mice.
The Ichneumonidae…slim, elegant wasps whose parasitoid efficiency helped support the grand idea that shook a superstitious world.
Aulacid wasp
The vibrating antennae were actually tapping the wood, a form of vibrational sounding or echo location¹. This is where the enlarged tibia come in, as these have been shown to be capable of sensing the vibration of the returning echoes².
The female ichneumon’s vibrating antennae are testing for the hollow passages in the wood where grubs are burrowing. Once she locates a grub, she pierces the wood with her ovipositor, and then places an egg on, in or near the grub. When the egg hatches, the larva will begin to feed on the grub, eventually killing it. The ichneumon larva will then pupate and eventually emerge from the wooden passage.
Darwin, when considering the claims of a beneficient intelligent designer, used the ichneumon as one example of why he could not believe this:
“But I own that I cannot see, as plainly as others do, & as I shd wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedlyin created the Ichneumonidæ with the y express intention of their feeding within the living bodies of caterpillars, or that tcat should play with mice.
The Ichneumonidae…slim, elegant wasps whose parasitoid efficiency helped support the grand idea that shook a superstitious world.