NSF Awards Grant for Spider Research
It’s tough being a male wolf spider. As they court females, they don’t know if they are being evaluated as a potential mate or the main course for dinner.
The complexity of spider behavior — the longstanding research interest of Alma College biologist Dave Clark — is the subject of a research project that has been awarded a three-year $485,000 grant from the National Science Foundation.
The project — which includes the development of animated spider images and the use of innovative digital video playback technology — is a collaboration between Alma College and the University of Cincinnati and a partnership with the Cincinnati Nature Center. Alma College students will spend a semester or summer session conducting research at the University of Cincinnati alongside graduate students and postdoctoral fellows.
Both laboratory and field components are included in the project, with a Spring Term opportunity at the Cincinnati Nature Center. Joining Clark as a co-principal investigator for the project is UC faculty researcher George Uetz.
“I’m very excited about this research and the opportunity for undergraduate students to conduct research in ways that will maximize their educational experience,” says Clark. “Our intent is to better understand how spiders communicate in complex environments.”
At Alma College, Clark has studied the different modes of communication used by a variety of animals, including lizards, fish and spiders.
For spiders, communication can take many forms, and some species use multiple modes, including visual communication, such as body posturing or leg waving. Spiders also can communicate by generating sounds, such as limb tapping, like a percussionist, or rubbing body parts. In addition, the spiders’ silk can communicate the presence of females or other males in the area.
For the current study, Clark and Uetz will investigate how the physical environment and the presence of the intended receivers, eavesdroppers and predators influence spider signals. High-definition computer animated versions of male spiders will be constructed at Alma College. Using digital video playback technology pioneered by the research team, animated spider images will be presented to wolf spiders and their predators on the handheld iPod Touch and iPad tablet computer.
“In our studies, we have found that male wolf spiders respond to the courtship of other males,” says Clark. “If they see courtship behavior by other males, that’s a signal to them that there may be a female in the area. As male density goes up, male courtship behavior increases. We want to continue to pursue how males use other males to find females.”
The problem for courting males, however, is that they are being evaluated for different purposes. Other males are using them to eavesdrop and find females. Females are evaluating them for their size and as a suitable mate — larger males translate into bigger and more eggs for the female.
“But females have a dual selective process,” says Clark. “Besides evaluating males as mates, females also are selecting males to eat. Females are choosy mates and not-so-choosy predators. Males, of course, are not interested in being the prey.”
And then there are other predators like toads and birds that will happily eat male spiders no matter what they look like.
“We want to look at both the influence of predators and how the physical environment affects detection and discrimination of male spider signals,” says Clark.
Clark and his students will use digital video playback technology to alter male signals and environmental backgrounds to test how spiders are detected and evaluated.
The faculty researchers will train and supervise teams of students in field data collection, video digitization and statistical analysis techniques. Students also will have the opportunity to conduct their own research projects to investigate related questions, search the literature using the Internet and make research presentations.
Posted: Thu, July 29th, 2010 at 1:42PM