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IU genome center helps shed light on insect evolution

After transcriptome workshop, Ph.D. student uses new skills to make discovery about moth’s adaptation to predators

Research and discovery Feb 14, 2019

Can the moth genome adapt to the threat of bats? One scientist thinks so, and he’s using knowledge acquired through the Indiana University-led National Center for Genome Analysis Support (NCGAS) to prove it.

Though many researchers believe insects are simple, mechanistic creatures without the ability to make adaptations beyond innate responses to stimuli, Scott D. Cinel, a Ph.D. student at the University of Florida, seeks to change this belief. Specifically, he would like to broaden public perception about insects as animals to acknowledge the breadth of their behavioral responses.

Cinel is part of a research group at the Florida Museum of Natural History McGuire Center for Lepidoptera and Biodiversity, where he focuses on a moth known as the corn earworm. (It is affectionately called a worm due to its “pest species” status for agriculture). The corn earworm, like some other species of moths and butterflies, has adapted functional ears. These ears are essentially simple membranes that have evolved in around 12 different places on the insect’s body.

The measure of a moth

The Helicoverpa zea, or corn earworm moth.

Image by Andy Reago and Chrissy McClarren.

These “ears” are believed ancestrally to have been used as stress and vibration receptors with other microsensor properties. Now, they have evolved to hear ultrasound, and it’s thought that this ability relates to bat predation—as bats are their primary predator.

In laboratory settings, it’s been shown that over long periods of time, exposure to synthetic ultrasound leads to long-term physiological responses. And, on an organismal level, the corn earworms are much less responsive to stimuli the longer they’ve been exposed to ultrasound.

Cinel and his collaborators are trying to get a whole measure of fitness, and note that both synthetic and bat ultrasound reduce the moth’s egg output by 25 percent. This reduction indicates long-term reproductive physiological adaptation to a high-sensory and high predation risk environment.

Cinel participated in NCGAS’s spring 2018 de novo transcriptome workshop. His new knowledge increased his transcriptome assembly by 35 more differentially transcribed genes. Among those were several aspects Cinel had hypothesized, which helped him construct a holistic story through these genes. Cinel reports that NCGAS has helped put a focus on the biological relevance of his work.

Ultimately, Cinel hopes his research will help the public think differently about pests in general, and pest-control methods especially, emphasizing biocontrol as an alternative to traditional methods like pesticides or clear-cutting.

“If we augment the population density of the native bat populations in agricultural settings and we can show that it would have an impact on the corn earworms’ long-term stress physiology then I believe we can champion biocontrol use within a public setting,” Cinel said.

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