Thread by @BugQuestions

Yeah, the interactions between moths and bats are totally awesome and should really be discussed.

There's actually a lot of controversy here...nobody really agrees on how exactly it's done but moths *do* disrupt bat attacks using sound.

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So, I guess the first question...why bats?

Although it's commonly said bats like mosquitoes, mosquitoes are too small to provide them with a good meal and don't really comprise a large part of their diet.

Instead, they like those big, juicy moths.

...and if you're a moth, bats are just about the scariest thing around. They're too big to fight, too agile to dodge, and they hunt using sound so camouflage isn't going to work in midair.

If you're a moth, you have to figure out how to share the sky.

The reason this is a complex question is that there's a number of ways to use sound. Luna moths appear to deflect it, but tiger moths make sound for various reasons using a speaker-like organ on their abdomen.

Here's a sampling of tiger moths that do that:

So...before we get into the sonar discussion, let's discuss those first three moths.

That first moth tastes bad and uses its clicks the same way a ladybug may use its colors. Bats have good eyesight, but generally hunt by sound so warning colors aren't as effective against them.

That second moth tastes alright (to that bats, that is...I don't actually know what they taste like), and makes sounds that sound a lot like the moths that taste bad.

It uses its sound to trick the bats into making it think it tastes bad.

That third moth belongs to a group of moths that all taste bad, so it advertises that using sound so the whole group is protected.

...and if you're a huge mimicry nerd like me, this is really cool because we could discuss what type of mimicry this really is for a long time.

Ultimately, the answer to that question would have to be answered using sonographs...and that's a bit beyond this thread. As we learn more, we ask more.

That's the fun thing about science...so many questions, so little time!

So, we actually know that there are different sound strategies used in different moths because they make completely different sounds.

The sounds of the 'jammers' are longer in duration and more constant than the ones who warn the bats/mimic the ones that warn the bats.

...and we do know that these moths can disrupt the bats while they're hunting. Put them into a room with a bat, and their ability to avoid the bats drops when you punch a hole in that sound producing organ.

...and we also know that bats have developed a number of countermeasures to this strategy.

So it's important to the moths for survival, and it's important enough to the bats for them to evolve around it.

It's a natural arms race.

So...we know that some moths use sound to disrupt how bats hunt.

How, exactly is this used?

Well, one hypothesis is that they startle the bats using the sound.

...but they appear to get used to it pretty quickly, so that's probably not the whole story.

See, bats can learn to avoid moths which make particular sounds. It's how we know about the moths that warn the bats...they learn to avoid those sounds after getting a few nasty mouthfuls in lab experiments.

We know that something's up with Bertholdia, because they taste good and the bats don't learn to avoid them. Their calls are also really complicated, unlike the ones used to warn the bats.

But there's another piece of the puzzle...they're made during the hunt's final moments.

A lot of the time, when people talk about these moths, the impression that's given is that the moths cancel the signals like noise cancelling headphones.

That's not...what's happening.

When a bat makes its final approach, it sends out a burst of sound. The echoes from that sound burst tell the bat exactly where the moth is, so it can capture the moth.

When the bats try to capture Bertholdia specifically, they appear to narrowly miss every single time.

So what appears to be happening is that the sound throws off the bat's approach; the sound made by the moths causes the bat to misjudge where the moth is and whiff the capture pretty consistently.

...and there's evidence that this strategy isn't just limited to moths. Tiger beetles also make sounds in response to bat calls, but what they're doing just isn't really known.

If you're interested in learning more about this, here's a great review paper which covers this topic and all the ways that bugs that fly at night manage to share the sky with bats!

Most of the images in this thread are from this paper.

pbrc.hawaii.edu/~danh/Neurodiv…