CGRER member and teammates make surprising discovery on parasitic wasps


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A wasp (species unknown) hangs out in a tree (via Creative Commons). 

Julia Poska | October 23, 2019

A recent discovery from the University of Iowa is helping fill-in knowledge gaps about some of the planet’s tiniest inhabitants.

University of Iowa CGRER member and biologist Andrew Forbes and teammates published a paper last month describing an unusual behavior of the “crypt-keeper” wasp. This parasitic species lays its eggs in “crypts,” bubble-like nurseries created in leaves in which other parasitic wasps lay their eggs. The baby crypt-keepers then eat their way through the other baby wasps to emerge from the leaves and into the world.

The study, published in Biology Letters, found that while the vast majority of parasite species are thought to be highly specialized and target just one host species, the crypt-keeper wasp is a parasite to at least six other species that create such “crypts” for their young.

Doctoral student Anna Ward, lead author of the paper, told the New York Times  that this finding helps shed light on important yet often overlooked truths about the ecosystem.

“With climate change, how can we know our true impact if we don’t even know what’s there?” Ward asked. 

 

 

Hymenoptera declared to be the most species rich animal order


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A parasitic wasp pauses on a leaf (Katja S/flickr)

Eden DeWald| May 23rd, 2018

University of Iowa professor Andrew Forbes has been conducting research that may intimidate those who aren’t fans of parasitic wasps. Forbes specializes in studying these wasps that belong to the Hymenoptera order, which also includes insects such as bees and ants.

In a preprint paper, meaning it has not yet been peer reviewed, Forbes asserts that the Hymenoptera order is more species rich than originally thought. Previously, Coleoptera— the beetle order, was thought to be the most speciose. However, Forbes’ specialization in parasitoid wasps allowed him to make the connection that there can be multiple species of parasitic wasps preying upon a single species of insect. Based on this ratio, one species of host insect to many different species of parasitic wasps, it would make sense that Hymenoptera is the most species rich order. The paper concludes that Hymenoptera has perhaps 2.5-3.2 times more species rich than Coleoptera.

Species richness is an important factor in general biodiversity. And although parasitic wasps may sound quite gruesome, they can provide useful services. Parasitic wasps prey on insects that are bothersome to humans such as garden pests like caterpillars, and even mosquitoes.