Webster is more high-strung than the other pet rose hair tarantulas that teacher Kris Chapman has kept in his biology classroom at Greenville High School in Mercer County.

The other spiders were tame enough for students to handle, but although a tarantula's bite is no more dangerous than a bee sting, Chapman is the only one allowed to touch Webster.

"She's real sensitive," he said.

Despite Webster's reputation, the grouchy tarantula wasn't the center of attention on the September afternoon that biologist Jonathan Pruitt visited Chapman's class. Instead, the AP biology students were busy with 26 African social spiders that Pruitt had brought to class in individual containers, ready for their spider personality tests.

This fall, Pruitt has been toting his spiders to 11 schools around the region as part of the University of Pittsburgh's biology outreach program, funded by the Howard Hughes Medical Institute.

In a typical visit, he teaches students about the scientific method and introduces them to his baby goliath bird-eating spider, which will eventually grow as large as a dinner plate. He also gets them to collect personality data for a real experiment.

In the Greenville AP biology class, students Madie Pochatko and Robert Wilt divided up the tasks for their spider tests. Mr. Wilt leaned in to shoot a puff of air at the tiny spider using an infant ear cleaning bulb, startling it into a huddle. Because Pochatko is wary of spiders, she claimed the less hands-on job of timing how long the arachnid maintained its defensive posture. As for most of the spiders tested that day, it didn't huddle for long, less than a minute.

But some of the spiders were more timid; one group had to keep an eye on their subject long after everyone else had finished and Pruitt's guest lecture was already under way. After 16 minutes, the spider finally raised the courage to resume scuttling around its plastic container.

Once all the spiders have been tested by students at the different schools, Pruitt will set up colonies with different mixes of personality to see how rapidly a bacterial disease spreads through each group and whether certain personalities act as "superspreaders."

Pruitt spends two days a week for most of the fall semester working with schools, as well as running a weeklong teacher's workshop in the summer. He says the extra work is rewarding and changes students' image of scientists.

"We have a stigma to overcome with the public. You know, the weird, old, white, unsociable, not charismatic, judgmental, gray-haired scientist in a lab coat," he said. "I don't think I'm what they expect."