A  biology professor and student researchers are discovering more about a species not documented in the United States until 2001.

By Carol Marcy


It looks like an ant you see on your deck railing or crawling across a leaf or down the stem of a plant. But it’s not an ant — it’s a spider — that wasn’t spotted in the United States until 2001.

Associate Professor of Biology Jennifer Apple first noticed the spiders in the college’s own Spencer J. Roemer Arboretum while she was observing nests of ants that kidnap other species and put them to work for their own colony.

“I’m watching these ants raiding each other, and I’d see these odd little things moving differently,” says Apple. “They were waving their front legs like antennae.” Eventually, Apple saw them more often and noticed the spiders were using the flags marking her ant colonies for their webbed shelters. “It gave me ideas on how I could study them,” she says.

The ant, on a leaf.

A female Myrmarachne. /Photo provided by Associate Professor Jennifer Apple

Apple has been studying the habits of this Eurasian species — also known as Myrmarachne formicaria — since 2017. The spider is not native to North America. The first sightings on this continent were reported by spider biologists in Ohio in 2001. The spider’s’ range has since spread into New York, Pennsylvania and Ontario, Canada. 

While the unique spiders don’t eat ants, their resemblance to ants may protect them from predators, says Apple, as many organisms avoid attacking ants.

Apple and her student research assistants have been examining the spider’s genetic diversity to learn more about whether their introduction resulted from a single chance event or if there have been multiple introductions from different populations. Thanks to the generosity of donors, the research has been supported in part through the Geneseo Foundation.

“When you have an introduced species, you don’t really know where it came from,” says Apple. “You can learn a little by looking at their patterns of genetic variation. If they are not genetically diverse, they may have come from a single introduction.”

Cassidy Mills ’22 worked as an assistant in Apple’s lab during her junior and senior years. She used molecular techniques to describe genetic variation in the North American population of this spider.

“It was not something I thought I would ever be able to do in college,” says Mills. During her experience, she presented her research work at conferences and symposiums, including the Northeast Natural History Conference and the American Arachnological Society Conference

“I really got a lot of exposure talking with other scientists and sharing my work,” says Mills. “I thought it was such a great opportunity.”

Mills assists with vaccine clinical trials at Q2 Solutions, a global clinical trial laboratory in Durham, N.C. “Seeing what goes on in the background before a vaccine is approved is pretty cool,” says Mills. She believes that her lab experience at Geneseo gave her a head start to landing the job. 

“I was able to talk to the people who were interviewing me about what I had done with Dr. Apple. It was the majority of our conversation.” 

The experience with genetic and ecological field methods students receive in her lab, Apple says, help prepare students for jobs, even if they don’t want to go into ecology.

Last semester, Apple spent sabbatical time in the Czech Republic, continuing her work with a spider expert at Masaryk University. She and her husband, Jeff Over, Distinguished Professor of Geological Sciences, also road-tripped through Europe to find the ant-mimicking spider in its native range. 

She found a surprise.

“Our experience was that it was much less common there than here,” says Apple. “After weeks of travel through western Europe, searching and finding other species of ant-mimicking spiders, we finally found our species, first in Spain, then in France and Italy.”

Apple hopes to compare the genotypes and levels of genetic variation of the spiders in their native and invaded ranges.

“We’ve been finding no genetic variations in local spiders, and I’m leaning toward the fact that perhaps this was a single introduction,” says Apple. She is collaborating with Associate Professor of Biology Josephine Reinhardt to develop more genetic markers that can provide further support for this conclusion and be used in comparisons with European spiders.

Of all the things Apple loves about this species of spider, she says watching them move is fascinating. “The males will engage in these displays and dances when they encounter each other, vying over territory or the attention of females,” says Apple. “They will open up those large jaws and size each other up.”

In addition to the genetic work in her lab, research questions exploring the behavior and habits of this spider have engaged 12 student researchers, who have presented their work at GREAT Day and other conferences.

Funding for research through the Geneseo Foundation includes the Roemer Summer Faculty Fellowship, the Geneseo Student Association, and the Undergraduate TRAC Grant Program.