Predatory Wasp and Giant Walkingstick Among Top New Species for 2015
By Harvey Black
A nasty wasp and a giant walkingstick have been named to the annual Top 10 New Species for 2015. The list is compiled by taxonomic specialists under the auspices of the International Institute of Species Exploration of the College of Environmental Science and Forestry of the State University of New York.
The bone-house wasp, Deuteragenia ossarium, found in China is “unique” in the words of its discoverers, Michael Staab of the University of Freiburg and colleagues, and is brutal in the measures it takes to protect its young. The researchers describe their findings in the journal PLOS ONE.
After building nests in hollow stems, the wasp makes separate compartments, which are separated by soil walls. Into each compartment the female drops a spider, which she has killed to nourish the offspring, and then lays an egg.
The wasp then fills the final cell with the bodies of as many as a dozen dead ants to create a barrier to the nest. The decaying ants provide chemicals — cuticular hydrocarbons that ward off any potential predators.
“This use of arthropods other than prey as part of the nesting behavior was not known before, neither in wasps nor in insects, nor in the entire animal kingdom,” Staab wrote in an email.
The chemicals give the nest the characteristic odor of an ant colony. And since ants are known to fiercely defend their colonies, the scent is likely meant to keep predators away. Moreover, most of the ants that are deposited are Pachycondyla astuta, a large, commonly-found species with a powerful sting.
“By using an abundant ant species, potential predators may have had contact with the species before and therefore avoid the species-specific scent,” Staab and his colleague wrote.
The researchers call the wasp the “bone house wasp” because the nests reminded them of bone houses or ossuaries found in graveyards.
The discovery of this insect was serendipitous.
“I was not specifically looking for new species, nor am I a taxonomist by training,” Staab explained in via email. “The new species was found during a large-scale study investigating the relationship between tree diversity and insect communities in subtropical China as part of large Chinese-German research unit. One of the collection methods used involved trap nests to attract solitary, cavity-nesting Hymenoptera. Trap nests consist of hollow plant material, usually reeds, and mimic the natural nesting conditions of all bee and wasp species that construct nests in cavities. The new species was one of the many species collected, and it was surprisingly abundant.”
Asia is also the site of the other Top 10 insect, a walkingstick called Phryganistria tamdaoensis. It is the second-longest insect known, measuring approximately nine inches. It was found in Vietnam by Joachim Breseel and Jerome Constant of the Royal Belgian Institute of Natural Sciences, who describe it in the European Journal of Taxonomy.
The researchers found it, along with another species and a subspecies, in what they term the “beautiful” Tam Dao National Park. They note that relatively little is known about these giant insects in Vietnam, “and that much work needs to be done describing and clarifying the status of existing taxa.”
The importance of this insect is due to its size, according to Quentin Wheeler, founding director of the International Institute for Species Exploration, an entomologist, and president of the College of Environmental Science and Forestry.
“If an insect nine inches long isn’t known to us yet, what else don’t we know? It’s a reminder there is so much work to be done to document insect diversity,” he said.
In years past, entomologists have trekked through Vietnam and simply overlooked this insect — a testament to its ability to camouflage itself.
Wheeler notes that this insect is not even the largest of the stick insects.
The whole effort of naming the Top 10 New Species annually is designed, he said, “to bring attention to the ‘biodiversity crisis.’ People should appreciate that there is so much to learn and perhaps not enough time to learn it. Even though it sounds impressive that we’re discovering 18,000 species a year, that rate has been flat since the 1940s. It’s important to share with the public that there is so much wonderful stuff to be discovered.”
Harvey Black is a freelance science writer. A long-time resident of Madison, Wisconsin, he has written for numerous publications including Environmental Health Perspectives, Scientific American Mind, New Scientist, The Scientist, and the Milwaukee Journal Sentinel.