NEW BRUNSWICK, N.J. — Any old pond will do. Michael L. May set out one recent Wednesday morning from his cramped office at the Rutgers University entomology building to collect a few dragonflies.

The road to a more pristine lagoon in a county park was closed, so Dr. May pulled off a highway two miles from campus and parked alongside a triangular pond lined with tall weeds and poison ivy and wild hibiscus serving up white shuttlecock flowers. With the traffic on U.S. Route 1 whizzing off in the distance, Dr. May, a bushy-bearded Florida native who just turned 65, grabbed his net and shuffled down the bank until his sneakers sank in the mud.

The pond was abuzz with activity. A green darner patrolled the surface like a fighter pilot. Bluets posed primly on slender reeds, and three stocky little Eastern amberwings chased one another around choice perches.

“There’s a pair copulating on the bamboo.” Dr. May pointed to two Eastern pondhawk dragonflies — green-and-black female and blue-dusted male — shimmering in the sunlight in a familiar heart shape.