Biologist seeks answers after census shows walkingstick decline

By Scott Marshall

Published: September 10, 2008

Linda Fink is looking for walkingsticks and needs help.

Fink, an entomologist and biology professor at Sweet Briar College, is researching the well-camouflaged creature to figure out why the population crashed near the Cub Creek Road property where she lives near the Lesesne State Forest.

Linda Fink asks that walkingstick hunters young and old e-mail her at to report a population or call her at (434) 381-6436.

“This is a very friendly bug,” said Fink, who asks that anyone who finds a population to give her permission to walk in their woods and collect or study them. If collectors want to, well, collect them, then she suggests putting them in a box for just a few days and then releasing them.

They tend to dry out and appear to need the moisture they get in their favorite leaves found in hardwood forests: oak, black locust and witch hazel.

From 1998-2006, Fink and her husband, Lincoln Brower, an expert on monarch butterflies, found anywhere from 75 to 250 in just an hour’s walk on their property. They found them on tree trunks as well as leaves and on understory shrubs.

“I was amazed how many there were” initially, she said. Fink and her students began studying them, to learn more about reproductive behavior and their natural enemies.

By 2007, the population had plummeted. She doesn’t yet know why some areas have large populations and others do not.

The females store sperm and fertilize the eggs when they lay them, and they hatch around April and spend the summer growing up before they die in the fall. The eggs hatch in the spring.

“Based on the observations I made, I started asking questions about their mating behavior,” she said. “Who is the dad? How do they choose the dad? Do males do anything to manipulate how she lays the egg?”

Fink has enlisted the help of Logan Fitzgerald, a Sweet Briar senior majoring in biochemistry and molecular biology who learned techniques in an advanced course titled Experimental Laboratory in Cell and Molecular Biology, taught by one of Fink’s colleagues, Robin Davies.

What they do know is that 2,000 kinds of walkingsticks exist in the wild, but just one species is found in Central Virginia, Diapheromera femorata. It usually is scarce, and a state entomologist told Fink that the Lesesne State Forest was the only population area he knew about.

Since 2003, Fink has conducted a standard census of walkingsticks on her property. In 2006, the population had dipped to just 10 percent of what it once was and hasn’t recovered.

Fink says the crash may have resulted from a combination of drought and a buildup of parasites, but she hopes to find out precisely why.

Walkingstick hunters will find they are as distinctive as they can be to spot.

Mature walkingsticks are brown, tan or green and up to three and a half inches long. Immature walkingsticks are green and one to three inches long. They are frequently found in pairs, with a skinny male alongside an only slightly stouter female. They are most noticeable in mid-September and their numbers drop rapidly in October.

Of important note to walkingstick hunters: They don’t bite or sting, they have no wings and can’t fly, they are not poisonous and they don’t eat crops or anything in humans’ gardens. And they aren’t considered a threat to forests.

They don’t bite or sting, they have no wings and can’t fly, they are not poisonous and they don’t eat crops or anything in humans’ gardens. And they aren’t considered a threat to forests.