Iowa farm native revels in a scientific world of insect ‘body snatchers’
Abigail Martens, a 25-year-old doctorate student from a western Iowa corn and soybean farm, explains her fascination with “beneficial” insects, including the parasitoids that go after such things as soybean aphids and kill them from within.
BROOKINGS, S.D. — Abigail Martens grew up on a corn and soybean farm her parents still run at Missouri Valley, Iowa, about 20 miles north of Omaha, Neb. As a kid, she’d bring home snakes, bullfrogs, caterpillars and fireflies.
Today, she has her bachelor’s in biology and master’s in plant science and now is working toward a doctorate in biological sciences at South Dakota State University, with a focus on entomology.
In 2015, Martens interned at the U.S. Department of Agriculture’s North Central Agricultural Research Laboratory in Brookings, becoming fascinated with parasitoids — an insect whose larvae live as parasites and eventually kill their hosts.
In 2017, Martens was a summer intern in the Smithsonian Institution in Washington, D.C. She compared that diversity to the diversity of parasites that attack aphids that are pests of soybeans or corn.
In 2018, while working on her master’s degree, she visited the Smithsonian Institution’s Natural History Museum and found a specimen of a wasp that had been collected by Harry Severin in South Dakota in 1945. It was a “singleton” — then collected from a new locality. Today, that’s helped her find a sister species in the same genus.
Martens’ insect world is full of drama.
First, she describes how a female wasp finds an aphid of the appropriate age and size. The wasp lays an egg in the aphid. The larvae hatches and begins eating “all of the delicious innards of the aphid,” until the aphid dies.
“The wasp spins a cocoon inside the aphid, pupates, and the adult wasp cuts a tiny hole in the aphid ‘mummy’ and the wasp emerges from the ‘port hole’” she said, smiling. “It’s kind of like in the movie ‘Alien,’ except without all of the blood and screaming. So it’s very fun.”
Full of possibility, Martens would like to end up working in a “museum collection,” something large on the order of the Smithsonian, or the California Academy of Sciences in San Francisco.
“I think museums are really important for the future of taxonomy,” she said. “A lot of your research — ecology, biocontrol, and things like that — all depend on having the taxonomy of your organism, right? So, knowing if it’s a species or a group of cryptic species (a species that looks identical, but has different DNA). Knowing what you’re releasing into the environment for, some, like, soybean aphid control, is really important.”
Soybean fields that are adjacent to more diverse areas, like an area with spruce trees, alfalfa or native plants, also show more diversity in aphid parasitoids.
“I love looking at the trophic associations — the plant, the things feed on the plant, and the things that feed on the things that feed on the plant," she said. “You have hierarchies of body snatching.”