Smithsonian Research Sheds New Light on Parasitic Wasp Species Diversity

Terry Erwin, a scientist at the Smithsonian’s National Museum of Natural History, in conjunction with researchers from Finland, the United Kingdom and U.S., has discovered 177 previously undescribed species of parasitic wasps from Central and South America. This drastically raises diversity estimates of a little-known group of parasitoid wasps to triple what was previously hypothesized. With more than an estimated 100,000 species worldwide, Ichneumonidae parasitic wasps are perhaps the largest family in the animal kingdom and play a key role in ecosystem functioning by controlling the population densities of the animals they use as hosts.

The study, published in the Proceedings of the Royal Society B, Oct. 3, illuminates the activities of the wasps, which lay their eggs in host species such as fungus gnats so that the developing wasp larva may consume their hosts for nutrition. It also reveals how large a group of tropical parasitoid wasp species has yet to be investigated, which is crucial to the understanding of tropical ecosystems. Discovering and describing the numerous, but poorly known, tropical parasitoids are particularly important because the loss of insects as valuable as parasitoids in a balanced ecosystem could significantly impact the composition of tropical environments.

“My two decade-long studies in monitoring the impact of an oil company building roads on the canopy insect fauna in the pristine Amazon rainforest resulted in this nice spin-off study for a young talented student to use part of the samples for her doctorate,” said Erwin, research entomologist and curator of beetles at the National Museum of Natural History. “The Smithsonian’s quality samples shared with Ecuador are available for a grand diversity of students to continue such studies.”

Collections from Erwin’s study plots in the eastern Ecuadorian rainforest accounted for 95 of the 177 newly discovered species. He worked alongside four additional scientists, including the lead author on the paper, Anu Veijalainen, a doctoral candidate at Turku University in Finland. The collaboration exposed the new ichneumonic species using traditional methods such as specimen observation, as well as more technically sophisticated population sampling and DNA barcoding methods. Some of the species found are so physically similar that they can only be identified as different species through analysis of their DNA structure.

The results of these studies bring to light the scientific need for research efforts that will describe these newly discovered species. These creatures can only be studied, understood and protected once they have been scientifically named. Once described, their importance to conservation efforts can be better understood and further explored.

The full study can be found online on the Proceedings of the Royal Society B website or in the October edition of The Royal Society’s print journal.

# # #

SI-443-2012