April 18, 2024

This Obscure Caterpillar Hides Venom Unlike Any Ever Seen In Insects : ScienceAlert

Caterpillars with extremely painful stings may have evolved with the help of ancient microbes, according to a new study led by scientists from the University of Queensland in Australia.

Their analysis revealed signs that a process known as horizontal gene transfer may have allowed toxin sequences to jump from bacteria to insects sometime in their evolutionary ages.

Although the caterpillar’s venom is still largely shrouded in mystery, researchers say its molecular secrets could be extremely beneficial to us.

The caterpillars that consume this venom are larvae of flannel moths (Megalope sp.); a fuzzy soft genus native to North and South America. They are sometimes called “puss caterpillars”, as their luxurious hairy bristle coats can make them look like caterpillar cats.

But that’s not the only nickname they have. Also known as “asp caterpillars,” danger lurks beneath those bristles.

The fuzzy fur of caterpillars is an arsenal of poisonous spines, which can inject powerful toxins into any predator or unsuspecting humans that come into contact with them.

This venom causes immediate and intense burning paincommonly evocative descriptions such as “being hit with a baseball bat,” “walking on hot coals,” or “the worst pain a patient has ever experienced,” the researchers wrote.

Some animal venoms have been useful to humans in recent years, and a growing field of research now sees them as potential gold mines. Certain snake and spider venoms, for example, have “tremendous potential” to inspire new medicines, the study’s authors point out.

And since caterpillar venoms have received little scientific attention so far, the researchers decided to investigate venom from some of the scariest caterpillars in the world.

Their study focused on two moth species – the southern flannel moth (Opercularis megalopyge) and the black-waved flannel moth (Megalopyge crispata) – to shed light on the anatomy, chemistry, and mode of action of venom systems in asp caterpillars.

They discovered a venom system that was very different, not only from closely related venomous caterpillars, but also from insects in general.

“We were surprised to find that asp caterpillar venom was completely different to anything we had seen before in insects,” say University of Queensland molecular entomologist Andrew Walker.

The asp caterpillar pins support the idea that it evolved independently from the venom of other insects, the researchers say. In fact, its origins seem to lie outside the animal kingdom entirely.

“When we looked at it more closely, we saw proteins that were very similar to some of the bacterial toxins that make you sick,” Walker say.

Specifically, asp caterpillar venom is similar to a type of bacterial toxin that binds itself to the cell surface, the researchers explain, assembling into a nut-like structure that rips holes in its target cell.

Although organisms usually pass genes down their offspring in a so-called vertical fashion, genes can sometimes be transferred across species – even those that are long related – in a less common way. horizontal process.

Previous research has found evidence of horizontal gene transfer from bacteria to other more complex creatures, including the transfer of genes involved in producing venom toxins.

In their new study, Walker and his colleagues say they have found evidence that major components of asp caterpillar venom such as venom toxins were recruited from genes that bacteria horizontally transferred to their ancestors.

Adult flannel elm. (Robert Aguilar/Smithsonian Environmental Research Center/Flickr/CC BY 2.0)

“The venom in these caterpillars has evolved through gene transfer from bacteria more than 400 million years ago,” Walker say.

Moths and butterflies have a wide range of strategies to protect themselves in their larval stages, and research like this can provide new insights into these amazing adaptations – including the different ways they have evolved and evolved.

“Many caterpillars have developed sophisticated defenses against predators, including cyanide droplets and protective glues that cause intense pain, and we are interested in understanding how they all connect,” Walker say.

In addition to sheer curiosity, people are studying these caterpillars in hopes of finding tangible rewards for our species.. Understanding venom can help us protect ourselves from it, and it can give us new ideas for developing or improving things like medicines and pesticides.

In the venom of an asp caterpillar, the newly identified mexican toxins cause severe pain by making holes in cells. If humans can imitate this tactic and change it, we may find ways to channel 400 million years of moth evolution into life-saving innovations rather than just painful stings.

“Cell-piercing toxins have particular potential in drug delivery because of their ability to enter cells,” Walker say.

“There may be a way to engineer the molecule to target beneficial drugs to healthy cells, or to selectively kill cancer cells.”

The study was published in Proceedings of the National Academy of Sciences.

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