Some Insects Taste With Their Feet and Hear With Their Wings

Insects put their senses in strange places, from ears on their bellies to noses on their legs—and eyes on their genitalia.

Ah, the breezy life of a butterfly. You’re outside all day, you have pretty wings and life is all about flowers.

One drawback: Your feet have taste receptors on them, which seems like it could get pretty unpleasant depending where you land.

The idea of walking around tasting our floor tile all day made us wonder: What are some of the other strange places insects have their sensory organs? It’s a human-centric question, but well, we’re only human.

Moms with Taste

For a butterfly, tasting with your feet isn’t gross. In fact, it’s a great way to find a delicious place to eat—and that’s why it’s how they shop for daycare for their offspring.

“You’ve got to make sure you’re getting those babies on the right plant,” says Katy Prudic, an entomologist at the University of Arizona. Butterflies can taste whether the plant they are standing on will be alright for their baby caterpillars to eat.

Similarly, crickets and locusts have taste receptors in their ovipositor, an organ that deposits eggs, so they can detect whether the dirt they’re using as a nursery is good for their offspring.

Parasitoid wasps can do a similar taste test with their antennae, and also perform antennae drumming on the surface of eggs where they might lay their eggs.

“It’s a lick, with rhythm and blues,” Prudic says.

Sound and Scent

Some moths have a kind of ear, called a tympanum, on their abdomen that can “detect the echolocation of bats hunting them,” says Adrian Carper, an entomologist at the Museum of Natural History at the University of Colorado in Boulder.

Three families of moths have this “ear” on their bellies—geometer and looper moths, snout moths, and hooktip and false owlet moths—making them ultrasensitive to ultrasound.

One species, the greater wax moth, can hear at 300 kHz, a higher frequency than any other animal. Some of these species will stop flying when they hear ultrasound.

Katydids have ears on their knees, which is fun,” Carper says, and in fact their relatives—grasshoppers, locusts and crickets—all have a tympanum just below the knee.

Smell Ya Later

“Smell helps insects find love, food and friends all while avoiding being eaten,” Prudic says, but alas, “they don't have noses.”

So how do they smell?

“Awful!” you may say, if you’ve heard that old joke, but actually insects can pick up on scent with their antennae, legs and even to have olfactory receptors on their genitals, Prudic says.

You See With Your What?

And as if insects are out to prove that you can do more than one thing with your nether regions, yellow swallowtail butterflies can see with their genitals.

Kentaro Arikawa of the Graduate University for Advanced Studies in Japan discovered photoreceptor cells in the genitalia of swallowtails in 1980. In a 2001 paper, he explains that this ability to see light is important for the insects’ reproduction.

Yellow swallowtails mate facing away from each other, and the male appears to use this light-sensitive organ to line up with the female. Arikawa found that when the photoreceptors were covered up, mating success decreased significantly, from 66 percent to around 28 percent.

Similarly, when females’ genital “eyes” were blacked out before they laid eggs, they had trouble detecting the surface of the leaf and attaching their eggs to it. When they couldn’t “see,” their success rate plummeted from 80 percent to about 15 percent or less.

In the paper Arikawa refers to butterflies seeing with their genitals as “hindsight.”

But we still don’t know whether genital hindsight is 20/20.

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