Video: Researching the feeding habits of Tetragnatha elongata

May 21, 2012

When men get hungry, they will do just about anything to satisfy their urge to eat.

Yevhen Drobot and Anne Danielson-Francois

That includes prying food from their mate鈥檚 jaws. Though uncommon in humans, some spiders will do just that to get their fill.

And Yevhen Drobot can prove it. The 黑料福利网 senior investigated the Tetragnatha elongata species to determine how male spiders feed.

http://youtu.be/IornKcl8Xmk

His curiosity stems from the fact that adult male spiders don鈥檛 build webs, which means they can鈥檛 capture prey and feed themselves.

So Drobot and Anne Danielson-Francois, assistant professor of biology, scoured the Rouge River a couple of summers ago in search of the spiders.

鈥淭hey鈥檙e actually quite tricky to find,鈥 Danielson-Francois said. 鈥淚 call them 鈥榤asters of camouflage.鈥 You could be looking at a branch that has five of them and you won鈥檛 even see them.鈥

The best spot to collect the spiders, according to Drobot, were along tree branches that hung over the river.

Drobot and Danielson-Francois, along with a few other 黑料福利网-Dearborn students, collected 275 spiders and took them back to the laboratory for staged mating trials.

Out of 165 trials, 43 male spiders attempted to steal food from their female mates. Fifteen of those attempts were successful.

The study is the first of its kind to reveal that male spiders can actively steal food from their mating partners, Drobot said.

鈥淭he first time we saw it, we didn鈥檛 really know why it happened,鈥 he said. 鈥淚t was really interesting.鈥

And what prompted many of the male spiders to steal their mate鈥檚 food wasn鈥檛 the treat itself, but rather the female鈥檚 size.

鈥淲hen the male鈥檚 body size was close to the female鈥檚 body size, he was more likely to steal the food,鈥 Danielson-Francois said. 鈥淚f the female was much heavier than him, it was much more difficult to get the food.鈥

One would assume that male spiders have an easy decision to make 鈥 mate with smaller females so they can steal food. But, according to Drobot, male spiders prefer mating with larger females because they have greater reproductive success.

鈥淭his finding suggests that, in this species, males may have a tradeoff between acquiring food resources from a smaller female and achieving greater reproductive success from mating with a more fecund, larger female,鈥 according to the research.

Drobot recently presented the findings as part of the College of Arts, Sciences, and Letters鈥 (CASL) Undergraduate Student Research Showcase. He was among dozens of CASL students who displayed their research on topics ranging from Socrates to chimpanzees.

鈥淥ur campus takes seriously the teacher-scholar model,鈥 said CASL Dean Jerold Hale. 鈥淥ne important facet of that model is engaging our students in the research process.鈥

Hale commended CASL faculty, including Danielson-Francois, for their ability to 鈥渟park the curiosity of their students by involving them in research.鈥

鈥淭he result is really excellent work,鈥 he said.

And as for Drobot, he plans to pursue a career in the medical field.

鈥淗e鈥檚 multitalented and his research skills will be invaluable in medical school,鈥 Danielson-Francois said. 鈥淚 cannot wait to see what he discovers next.鈥