‘Hanging out with bugs’ at Scoville

SALISBURY — Michael LaScaleia, a scientist with the Arnold Arboretum in Boston, took an audience through the strange and wonderful world of caterpillars and invasive plants at the Scoville Memorial Library Thursday, June 12.

The talk was sponsored by the library and the Salisbury Association Land Trust.

LaScaleia, with infectious enthusiasm, gave a precis of his academic career. A highlight was a study of dung beetles.

“Dung beetles play a huge role in the African savannah, because there is so much, um, poop” he said.

He showed a photo of himself during the dung beetle phase, looking somewhat grimy and disheveled.

He said it was a critical experience.

“I thought, this is my thing. I love being dirty. I love hanging out with bugs.”

Lately he has been working on why, exactly, invasive plants succeed in New England.

Viburnum dilatatum (aka linden arrowood) is native to East Asia and was introduced in this country in the early 19th century.

“We already had a very similar plant — Viburnum acerifolium” (aka maple-leaved arrowood).

LaScaleia wanted to know why caterpillars will eat the native plant but not the exotic version.

He provided a brief and moving picture of the plight of the caterpillar.

“Even caterpillars don’t want to be caterpillars.”

Hence their eternal struggle to turn into moths or butterflies.

“Birds eat them. Also spiders, wasps and ants,” he continued.

“They have a long development cycle. They have to shed their own skin, and if they can’t they asphyxiate.”

“It’s truly awful.”

LaScaleia is testing the Enemy Release Hypothesis. The gist of this is when a plant is introduced to a new, faraway location, such as New England from East Asia, it leaves behind the predators that kept it in check on its home turf. In the new location, the native predators (such as caterpillars) aren’t much interested in the new arrivals, which allows the plants to spread, causing consternation and dismay.

Scientists are now working on why specialist caterpillars won’t eat invasives. Specialist caterpillars are picky and only eat specific plants, as opposed to generalist caterpillars, which are broad-minded and will eat almost anything.

If the goal is controlling the spread of invasive plants, can these specialist caterpillars be assisted in developing an appetite for invasives?

One idea is to take advantage of the tendency of invasive Japanese barberry to start growing earlier in the spring than its native counterpart by developing a caterpillar that also gets going earlier in the spring.

After LaScaleia wrapped up the talk, he and a group hiked over to the Land Trust’s Vincent Preserve for some field work.