Why A Moth Grew Tentacles? - Creatonotos gangis

[00:00:00]You may be familiar with tiger moths.

[00:00:03]They are a fairly widespread group of graphic-looking black and white moths, sometimes with beautiful red, pink, or orange body markings.

[00:00:12]Their caterpillars are the recognizable woolly bears, large, stinging caterpillars who supposedly can predict the weather.

[00:00:22]But there is more to these insects.

[00:00:25]This is the Baphomet moth, a stinking, poisonous, tentacled monster.

[00:00:32]It is also a moth whose caterpillar makes decisions that will decide months later whether the adult can find a mate.

[00:00:41]To understand the strange tentacles, you have to understand its bigger life cycle and a male that turns itself inside out.

[00:00:51]Across Australia and Southeast Asia, the Baphomet moth, Creatonotos gangis, can be found around nightlights.

[00:01:00]At rest, it draws no attention.

[00:01:03]Pale forewings with dark lines hiding a shockingly red-orange body.

[00:01:08]You might not even give it a second glance. A typical-looking tiger moth.

[00:01:13]Half an hour after sunset, though, the tip of its abdomen swells, splits open, and four enormous hair-covered tubes balloon outward, reaching past the full length of the moth that produced them.

[00:01:27]But what you see isn't a threat. It's an advertisement for mating. This bizarre horror display starts in childhood and depends on the caterpillar's diet. These caterpillars will eat almost anything, but unlike many other insects, these caterpillars will seek out poisonous [music] plants.

[00:01:47]Specifically, they are looking for plants containing a class of poisons called pyrrolizidine alkaloids, plants like rattlepods and heliotropes.

[00:01:58]The caterpillar deliberately consumes toxins that would sicken other animals.

[00:02:04]In larger animals, these pyrrolizidine alkaloids cause acute liver failure. But rather than being harmed, the caterpillar stores the poison.

[00:02:14]It moves the poison into its own tissues, stores it in a stabilized harmless form, [music] and holds onto it for later.

[00:02:23]The caterpillar carrying these compounds is unpalatable to the predators that would otherwise eat it.

[00:02:29]The stored plant toxins are a chemical shield, and the chemical shield survives the caterpillar's metamorphosis.

[00:02:37]It passes intact into the body of the adult moth.

[00:02:41]But back to the male and the four tubes erupting from its abdomen.

[00:02:46]These are called the coremata, and they are scent organs everted from the body like a sock turning itself inside out with a pump of internal hydraulic pressure.

[00:02:58]Each tube is sheathed in roughly 3,000 specialized scales whose job is to release scent into the air.

[00:03:07]And the size of the coremata is dependent on how much plant poison was eaten [music] as a caterpillar.

[00:03:14]Consider two male caterpillars. One feeds on plants rich in this poison, the other is raised without any of it. When they become adults, the first unfurls four thick, fully formed tubes covered in scales.

[00:03:29]The second has almost nothing. Two stunted stalks bearing only a few hairs and no scent to speak of.

[00:03:37]The relationship between size and scent and poison is proportional. The more poison the caterpillar eats, the larger these organs are on the adult.

[00:03:49]So, this is what those tentacles are doing. They are announcing a strong male who ate enormous amounts of poison in childhood. And these poisons will be passed to the female in mating.

[00:04:01]So, she can add it to her own supply of poison >> [music] >> and pass the combined gift to her eggs, which are then defended against predators and parasites before they hatch.

[00:04:13]A female choosing the strongest smelling male is choosing the best provisioned father for her offspring.

[00:04:20]But during these mating displays, rival males also track the scent plumes to its source [music] and settle nearby, unfurling their own corema and adding their scent to the growing plume.

[00:04:33]What forms is a gathering of males, all advertising together, a chemical chorus, pooling into a single plume far stronger than any one moth could cause alone.

[00:04:46]Once this male chorus has been calling for a while, females start to show up, homing in on the combined signal.

[00:04:54]When a female reaches the perch and makes contact, the male's tubes collapse and the pair mate. As the male signaling fades, virgin females take up the work for themselves, releasing their own unique scent to draw in males who missed the first round of mating.

[00:05:11]Two waves of signaling in a single night, although we aren't quite sure why the females do it.