City bees line nests with plastic bags

Bits of your plastic shopping bags could end up in an unexpected place: a bee’s nest.

Researchers have found two bee species in Canada using plastic to help build the brood cells in their nests. This behavior might actually be a clever way for bees to adapt to life in the city, where plastic is ubiquitous. It’s not the first time that animals have been found using strange materials; for example, some finches and sparrows in Mexico line their nests with pieces of cigarette butts.

The authors were studying bees from the family Megachilidae, which normally use plants, pebbles, mud, and other natural materials in nests. The species Megachile rotundata typically collects flower petals and leaves, and the species Megachile campanulae uses resins from plants.

The researchers examined bee nests in the Toronto area, and “during inspection of the nesting tubes we discovered non-natural materials built into the nests of two different bee species,” they write in Ecosphere. A M. campanulae nest contained an unidentified “whitish green material”, so the team performed chemical analyses to try and figure out what it was. The material contained calcium, titanium, and iron and appeared to be similar to polyurethane-based sealants used on buildings.

In three brood cells in a M. rotundata nest, about a quarter of the leaves had been replaced by pieces of plastic bag. Marks from the bees’ mandibles on the plastic also looked different than those on the leaves. “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,” said co-author Andrew Moore of the University of Guelph in Ontario in a press release.

Larvae from the brood cells survived, and the authors suggest that plastic might even keep parasites out of the nest. But plastic might pose other problems, such as hindering the bees’ movement or breathing. — Roberta Kwok | 13 February 2014

Source: MacIvor, J.S. and A.E. Moore. 2013. Bees collect polyurethane and polyethylene plastics as novel nest materials. Ecosphere doi: 10.1890/ES13-00308.1.

Image © Agricultural Research Service | Wikimedia Commons