Researchers from the University of Guelph found that at least two species of urban bees use plastic waste to build their hives.

Human housing options have evolved from caves to tree sheds to huts and now to concrete buildings. So why should bees stick to their traditional hives! Researchers from the University of Guelph made an interesting discovery while observing these busy insects.

They found that at least two species of urban bees use plastic waste to build their hives, according to a press release. Plastic waste pervades the global landscape. While plastic materials have had a negative impact on quite a few animals and insects, a few of them have also adopted a more "plastic-rich" environment.

"We found two solitary bee species using plastic in place of natural nest building materials, which suggests innovative use of common urban materials," lead author Scott MacIvor, a doctoral student at York University, said in a statement.

The study began with MacIvor discovering some "grey goo" in the nest of a bee species known as Megachile campanulae. This species generally uses plant resin to build their hives.

On further analyses of the substance, U of G's Andrew Moore found that this bee species sometimes replaced plant resins with polyurethane-based exterior building sealant, such as caulking. He also found that the bee species Megachile rotundata applied a similar tactic, using pieces of polyethylene-based plastic bags to construct its brood cells.

"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.

Researches confirmed that since bees use different techniques to chew leaves and plastic, it rules out the possibility that these pieces of plastic were accidently collected by the bees. Researcher also eliminated the possibility plastic was used as an alternative to leaves when the latter was unavailable because the leaves used by these bees to build their nests can easily be found everywhere.

One reason for this could be because plastic nests physically impede parasites more effectively than leaves.

"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.

Findings of the study were recently published in the journal Ecosphere.