Second Longest Insect In The World Discovered In Vietnam

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Justine Alford

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361 Second Longest Insect In The World Discovered In Vietnam
Bresseel & Constant, Royal Belgian Institute of Natural Sciences

Nope, that’s not a stick. It is in fact a stick insect, and a whopping great huge one at that. This gentle giant, Phryganistria heusii yentuensis, is new to science and was discovered recently during an expedition to Vietnam, alongside two other previously unknown stick insect species. And if the picture doesn’t do it justice, it’s more than a foot long (32 centimeters). But if you then stretch its front legs out, it measures more than half a meter (21 inches) in total length, earning it the title of the second biggest living insect so far described.

The discoveries, which are reported in the European Journal of Taxonomy, were made by a duo of researchers from the Royal Belgium Institute of National Sciences as they scoured dense Vietnamese and Chinese forests in search of insects. Vietnam, and part of southern China, is part of the Indo-Burma region, which is in the world’s top 10 biodiversity “hotspots,” meaning it is one of our planet’s most biologically rich regions. Unfortunately, alongside housing an abundance of endemic plant and animal species, it is also home to more humans than any other hotspot, meaning the region is threatened by habitat loss and over-exploitation of resources.


Given that this area is so rich in life, it’s not surprising that researchers regularly describe new species here. Furthermore, although 750,000 living species of insect have so far been described, scientists estimate that there’s probably a million more awaiting discovery, so there’s no shortage of work for entomologists. However spotting insects is not always easy; many are tiny, or well camouflaged, or hide away in difficult places. And stick insects are no exception, because they obviously look remarkably similar to twigs. But never fear, because scientists have come up with a very sophisticated technique to increase their chances of finding them: beating. Basically, they smack trees with a stick which scares the insects out, and then the scientists catch them with a sheet.  

This advanced methodology helped the researchers discover several previously unknown species, but the foot long giant was spotted just chilling out on a bush. It’s the second longest known living insect after another species of stick insect found in Borneo. This behemoth, Phobaeticus chani, measures an impressive 36 centimeters.

Alongside hunting for new species, the researchers had another mission. Stick insects show sexual dimorphism, which basically means that females and males look remarkably different in terms of both size and coloration. So, back in the earlier days of entomology, many specimens were wrongly classified as different species because they looked different, when in fact they were just males and females of the same species. So part of this ongoing project is also to painstakingly compare museum specimens and literature with specimens collected in the field to try and correct classification mistakes.

The authors are also collaborating with Vietnamese scientists to try and generate a reference museum collection, and develop a set of key markers to assist insect identification. According to the team, they anticipate that they will double the number of documented stick insect species in this region over the next few years.


[Via European Journal of TaxonomyWired and]


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