Feb 20, 2019 | Updated: 10:02 AM EST

Parasitic 'Dementor' Wasp Leaves Prey Without Free Will

May 28, 2015 12:39 AM EDT


You may think a wasp that can zombify its prey with venom in order to eat it alive sounds like the stuff of nightmares, but it's actually the stuff of biodiversity. Called the dementor wasp, this terrifying insect was just discovered last year-along with 138 other new species-in the Greater Mekong Region of Asia, the World Wildlife Fund (WWF) reports today.

Named for the dementors of Harry Potter fame, the wasp hunts some of Nature's other icky creatures: cockroaches. With disturbing accuracy, the dementor wasp locates the neural centers on the undersides of cockroaches in order to inject them with paralyzing venom. According to WWF, the venom "blocks receptors of the neurotransmitter octopamine, which is involved in the initiation of spontaneous movement. With this blocked, the cockroach is still capable of movement, but is unable to direct its own body."

In other words, the cockroach's muscles work, but it lacks the will to move. The wasp, also called ampulex dementor, is then free to devour the stunned and paralyzed cockroach alive after dragging it by its antennae to wherever the wasp can eat in safety. No word from WWF on whether there's any cockroach-y screaming, but unless you're in Thailand, you won't hear it anyway.

Still, scientists remind us that even soul-sucking wasps are beautiful in terms of biological diversity.

"It's amazing that in this day and age we're still finding such large numbers of new species. And not only that, such bizarre and beautiful species ... that are also quite large and recognizable to most people," WWF national species manager, Darren Grover says.

The report also discusses another new and startling insight: Phryganistria heusii yentuensis, which at 54 centimeters long is the world's second-longest insect. That's right: there's an even bigger one somewhere, probably in Vietnam, which stick insects apparently love: the researchers who led the expedition say they found more than 150 new stick insect species there.

"Three of the biggest insects have just been described last year. There are more for sure!" says Jerome Constant, leader of the expedition.

The team found 90 plants, 23 reptiles, 16 amphibians, nine fish, and one mammal in 2014. Among them was a thorny frog that changes hues depending on what time it is; during the day it is yellow and brown, while at night it dresses up in pink and yellow. They also discovered a new, distinctly-marked wolf snake species in Cambodia. And the newly-identified bent-toed gecko found in 2014 became the 10,000th reptile species identified by scientists-after 15 other varieties of bent-toed geckos were discovered in the Greater Mekong region last year. This makes the genus home to 197 species of bent-toed geckos-a distinction, since there are 15 species in any other gecko genus.

Researchers also found a crocodile newt species just in time for people-the most terrifying animals of all, as it turns out-to want them for pets; two of these Myanmar natives have already been seen in European pet stores. The tiny bat discovered last year may escape that particular fate by virtue of its long, sharp, off-putting fangs. Not so the two new orchid species, as they were already being traded in Chatuchak Market, Bangkok, before they were scientifically identified.

All of this should highlight the fact that scientists are racing against time. They are working to document new species before they disappear; this is the only hope they have of trying to save them.

"[T]here's significant threats to all the species in these areas - large dam projects, roads, other types of infrastructure - which will mean some of these species may be lost just as we're finding them."

Between 1997 and 2014 three new species a week were found in the Greater Mekong on average-more than 2,200 total. The WWF report states that the dizzying biodiversity here supports about 240 million people in the region who rely upon these natural systems for their culture, livelihoods, and food. Unfortunately, the Critical Ecosystem Partnership Fund ranks the Greater Mekong among the five most threatened biodiversity hotspots worldwide.

The WWF reports that construction of dams, roads, and other infrastructure projects are what most threatens the Greater Mekong Region. Hydropower developments such as the Laotian Xayaburi Dam which is poised to be the first obstacle to the lower Mekong River have a serious impact on the entire region. Alongside the threats posed by climate change and its higher sea levels and temperatures-and of course the ever-present problem of poaching-the region is in trouble.

"If these projects go ahead, the loss will be very sudden. These dam projects in particular are massive and will flood extensive areas, including many that scientists haven't had the opportunity to explore," Grover says.

"We've only skimmed the surface of new discoveries in the Greater Mekong," WWF expert Thomas Gray says." One wonders how many species have disappeared before they were even discovered."

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