Life Sciences

April 23, 2002

Resistant Roaches

huge cockroaches
Alec Matson

"These fly," says Annie Steed (entomology). She tilted the lid of a small plastic box containing hundreds of pale green Cuban cockroaches. Picking another box, she lifted the lid right off. "This is the German cockroach. It's one of the more common ones in the U.S." Steed is studying the cockroaches' resistance to chlorpyrifos, a nerve poison used as an insecticide. "We've found that German cockroaches can be highly resistant," says Steed. "They eat bait containing the poison but do not die. The more tolerant ones can live long enough to reproduce, and their nymphs—baby cockroaches—often have the same level of resistance." Before they die, resistant cockroaches also defecate a significant amount of the poison. "Because chlorpyrifos is a health hazard to humans, we're trying to determine how much of it is actually getting into the environment. We need to identify and understand the scale of the problem so that we can make recommendations and take appropriate action."

Liliana M. Naydan

Comparing Cotton

woman in black shirt standing behind experiment setup. hands on the lab bench.
Jordan Knott

Polly Leonhard (crop and soil sciences) has been studying cotton since ninth grade. "I grow my own plants, which is hard to do since the growing season is much shorter in Pennsylvania than in the South," Leonhard says. Comparing white and colored varieties, she's found that white cotton has longer and stronger fibers than brown, green, or red. Breeders have selectively bred for better fiber properties in white cotton, she explains. "Companies in the U.S. prefer using white cotton; that's why breeders breed it. But some people like naturally colored cotton fabric that's not chemically dyed. I'm by no means a plant breeder yet—the goal of my research is just to compare the fiber properties—but in the future, breeding a better colored cotton would be interesting."

Liliana M. Naydan

The Stressed Out Earth

research poster on easel in front of inside HUB ballroom windows
Jeff Shaeffer

What happens when the stress around fault zones changes? Erica Schneider (geosciences), who investigated fault relationships in Wellington, New Zealand, explains that faults are areas of fractured rocks of the Earth's outer shell. Fault relationships are the effect of one fault's movements on another's. The Wellington fault, she found, is at high risk for an increase in stress due to large movements on the Wairarapa fault or the Sheppard's Gully fault. An increase in stress reduces the time interval until the next earthquake. Future research will uncover how a single seismic event on those faults will increase or decrease stress.

Edward Vassallo

Dam Diversity

woman in white sweater with green critter in her palm
Jordon Knott

What difference does a dam make? By measuring the bug populations in the water before and after removal of a dam on the Conestoga River in Lancaster County, Heather Calaman (biology) found that the dam was suppressing diversity. Before the dam was removed, she found 554 critters from 16 families. Afterwards she found 3,783 from 30 families. Calaman believes the increase was due to the high amount of oxygen available in the faster flowing water.

So Much to Sea

Aquarium full of coral; young man looking in from the back
Nancy Carpenter

When most students pass the aquarium in Penn State’s HUB-Robeson Building, they glimpse bright, striped tropical fish darting in and out of lavender and green corals. When Nicholas Hartman (chemistry) peers into the 530-gallon tank, he sees a microscopic universe. The coral reef tank, donated by the Class of 1999, simulates a typical Indo-Pacific reef, such as those near Hawaii and Fiji. Hartman studies the corals and the organisms that live on them. These organisms give the corals their color and give researchers a glimpse into their health: If a coral begins to lose its shade, it is dying. With a scanning electron microscope, Hartman can see tiny objects on a coral’s calcium carbonate skeleton and examine crystals of skeleton. He also uses X-ray tomography, which, like a CAT scan, allows him to see inside a coral without cutting it open.

Elizabeth M. Stieber

Last Updated April 23, 2002