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.
In both cases, larvae successfully developed from the plastic-lined nests. In fact, the bees emerged parasite-free, suggesting plastic nests may physically impede parasites, the study said.
The nests containing plastic were among more than 200 artificial nest boxes monitored by MacIvor as part of a large-scale investigation of the ecology of urban bees and wasps, a project involving numerous citizen scientists.
The nest boxes are located in Toronto and the surrounding region in backyards, community gardens and parks and on green roofs. They are used by a variety of bee species.
"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.
|Contact: Scott MacIvor|
University of Guelph