Fruit fly evolution gives way to new wasp species

OCTOBER 31, 2015

by Chuck Bednar

   

It’s the evolutionary version of the domino effect: ongoing changes in one species of fruit fly have played a key role in the rise of three new types of predatory wasps, according to research published earlier this week by the Proceedings of the National Academy of Sciences.

In the new study, biologists from Rice University, the University of Notre Dame, Michigan State University, the University of Iowa, and the University of Florida explained that they were looking at the “apple maggot,” a fruit fly species known as Rhagoletis pomonella, that previous work had found was becoming two different species due to feeding and mating habit changes.

That evolutionary split is driven by differently timed fruiting cycles between apple trees, which the study authors explained are preferred by some Rhagoletis, and the North American hawthorn, where the fruit flies had traditionally laid their eggs. The new study expands on that earlier work to investigate the impact of those changes on wasps known to be parasites for Rhagoletis.

Specimens from three different species of wasp were collected from various different fruit fly host plants in the wild. Analysis of those wasps revealed that just like Rhagoletis, they were in the process of diverging into different species, distinct both in terms of their genes and in terms of host-associated physiology and behavior.

One good evolutionary adaptation deserves another

Study co-author Scott Egan, an evolutionary biologist and assistant professor of biosciences at Rice, explained in a statement that the study “addresses one of the central questions in biology: How do new forms of life originate?” He added that it examines “sequential speciation,” a type of evolutionary process that recognizes that adaptation is not an isolated process.

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