A biology professor at UConn’s Waterbury campus and a high school biology teacher at the Kent School, have documented parasitic behavior in some beetles that could endanger rare reptiles.
| Stephen Trumbo, an associate professor of ecology and evolutionary biology, displays a case of beetles from the Collections Facility in the Biology/Physics Building.
|Photo by Daniel Buttrey
The “interesting and bizarre” behavior of the burying beetle known as Nicrophorus pustulatus is a rare example of an insect preying on a vertebrate’s eggs, says Stephen Trumbo, associate professor of ecology and evolutionary biology in the College of Liberal Arts and Sciences.
Trumbo has published widely in scientific journals on the burying beetle, which is known for burying the corpses of dead mice and feeding them to its larvae.
A few years ago, an adult burying beetle was found in a snake nest, tending its larvae, which were feeding on snake eggs.
No insect had been observed previously in this type of parasitic behavior toward a vertebrate, says Trumbo.
Trumbo and Garrison Smith, a biology teacher at the Kent School who pursued a master’s degree in Trumbo’s laboratory, tested the field observation in the lab.
The results of their work will soon be published in a paper in the Journal of Evolutionary Biology. Smith, who earned his master’s degree from the University of Arizona but did his thesis experiments in Trumbo’s lab, is the lead author.
They found that this particular species of burying beetle, which is found in Connecticut and elsewhere in the Eastern United States, does feed and thrive on snake eggs.
Other species of burying beetle walked right over the snake eggs, ignoring them.
The pustulatus beetle also behaved differently toward other prey. Although in the lab it used dead mice to feed its young – perhaps a holdover from ancestral behavior, Trumbo says – in the field it does not respond to dead songbirds or mice, as other burying beetles do.
The unusual behavior of this species of burying beetle may indicate an evolutionary transition from one prey to another, he says.
Burying beetles are also rarities in the insect world for biparental investment, says Smith – both parents help feed the young.
The Nicrophorus pustulatus beetle has been found in fox snake and rat snake nests.
Rat snakes are a threatened species in Massachusetts and have protected status in Connecticut because of declining populations.
Smith is now involving his Kent School biology students in further experiments on the species.
Burying beetles are efficient at doing three things, Smith says – they strip a mouse carcass of fur, round it into a ball, and bury it. His students are rating how well three species of the beetle do this.
“If they’re losing some of these behaviors,” he adds, “it could indicate a host shift from carcass to eggs.”