Study: Bees using manmade materials to build nests

Megachile rotundata, an alfalfa leafcutting bee. (Photo by Peggy Greb / USDA Agricultural Research Service)
Megachile rotundata, an alfalfa leafcutting bee. (Photo by Peggy Greb / USDA Agricultural Research Service)
It’s no excuse to litter, but a new study has found that some bees use bits of plastic bags and plastic building materials to construct their nests. It’s an important discovery because it shows bees’ resourcefulness and flexibility in adapting to a human-dominated world, says Scott MacIvor, the study’s lead author. “Plastic waste pervades the global landscape,” said MacIvor. Although researchers have shown adverse impacts of the material on species and the ecosystem, few scientists have observed insects adapting to a plastic-rich environment, he said.

Figuring out that the bees were using plastics in place of natural materials took some detective work by Andrew Moore, of the University of Guelph, in Ontario, Canada. Moore analyzed a grey “goo” that MacIvor discovered in the nests of one kind of bee, Megachile campanulae, which uses plant resins to build its nests, “Scott thought it might be chewing gum originally,” Moore said. Turns out that M. campanulae was occasionally replacing plant resins with polyurethane-based exterior building sealant, such as caulking, in its brood cells–created in a nest to rear larva.

The researchers also discovered another kind of bee, Megachile rotundata, an alfalfa leafcutter, was using pieces of polyethylene-based plastic bags to construct its brood cells. The glossy plastic replaced almost one-quarter of the cut leaves normally used to build each cell. Markings showed that the bees chewed the plastic differently than they did leaves, suggesting that the insects had not incidentally collected plastic. Nor were leaves hard to find for the bees in the study. “The plastic materials had been gathered by the bees, and then worked — chewed up and spit out like gum — to form something new that they could use,” Moore said.

“The novel use of plastics in the nests of bees could reflect the ecologically adaptive traits necessary for survival in an increasingly human-dominated environment,” MacIvor said.

SOURCES: Press Release