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World’s Second-Longest Insect Found in Vietnam

stick insect

Image credit: Bresseel & Constant, Royal Belgian Institute of Natural Sciences

This gentle huge stick insect called as Phryganistria heusii yentuensis has been discovered during the recent scientific expedition to Vietnam, alongside two other stick insect species which are unknown previously.

This stick insect has a long foot of 32 centimeters, but when its front legs are stretched out, it would be more than half a meter long in total length, thus making it as the second biggest living insect described until now.

Being reported in the European Journal of Taxonomy, such e discoveries were made by two scientists of the Royal Belgium Institute of National Sciences when they were searching for insects in the dense Vietnamese and Chinese forests.  Vietnam as well as some part in South China belongs to the Indo-Burma region, which is regarded as one of top 10 hotspots in terms of biodiversity in the world, because it is one of the most biologically rich areas on Earth. It has to be admitted that although such region is full of endemic plant and animal species, it is also the place where more people are living than any other hotspot, so it has been increasingly threatened due to over-exploitation of resources and habitat loss.

Thanks to the fact that this region is so rich in life, it is here where new species have been discovered by researchers on a regular basis. In addition, so far 750,000 living species of insect have been found, but it is estimated by scientists that possibly there should be more than a million to be discovered yet; therefore more work should be done by entomologists in this regard.

However spotting insects is not an easy task, because many insects are tiny, or good at camouflaging, or hide themselves in difficult places. The same thing happens to stick insects as well, because they look obviously quite similar to twigs. However, it is no longer difficult for scientists, and they have already tried a very sophisticated technique in order to get more chances in finding them. That is beating, in which scientists strike trees with a stick so as to scare the insects out, which would help them catch insects with a sheet.

By application of such advanced method, the researchers have already discovered several species unknown before. However the foot long giant was spotted just chilling out on a bush. In addition to another species of stick insect called as Phobaeticus chani measuring 36 centimeters, which was discovered in Borneo, this one is the second longest living insect known so far.

Apart from seeking for new species, the researchers were also engaged in new mission. Stick insects demonstrate sexual dimorphism, which generally means that females and males look quite different in regard to their size as well as coloration. Therefore, in the earlier developmental stages of entomology, many specimens had been classified incorrectly as different species because of their different appearance. However actually they were just males and females of the same species. As a result, the researchers are making painstaking efforts to make a comparison of specimens displayed in museum and described in literature with specimens collected in the field so as to correct previous classification mistakes.

In collaboration with Vietnamese scientists, the authors are trying to create a reference museum collection and work out a set of key markers helping insect identification. According to their anticipation, they would double the number of documented stick insect species in this area in the coming  few years.

Source: Wired and Sci-news.com

Journal reference: Bresseel, Joachim, and Jérôme Constant. “Giant Sticks from Vietnam and China, with three new taxa including the second longest insect known to date (Phasmatodea, Phasmatidae, Clitumninae, Pharnaciini).” European Journal of Taxonomy 104 (2014).