Bees Are Building Nests with Our Waste Plastic

If you picture a bee nest (yes, bees build nests), you probably think of a natural haven of leafy comfort. Normally, you’d be right, but biologists studying two types of bee recently found that the insects have moved with the times: They’re now incorporating plastic in their designs.

In a paper published in the Ecological Society of America's journal Ecosphere, researchers from York University and the University of Guelph in Canada explained that while plastic waste has previously been shown to have devastating impacts on the environment, less attention has been given to the resourcefulness of species in the face of their changing surroundings. "Plastic waste pervades the global landscape," they wrote. "Although adverse impacts on both species and ecosystems have been documented, there are few observations of behavioral flexibility and adaptation in species, especially insects, to increasingly plastic-rich environments."

Led by York University PhD candidate Scott MacIvor, they set up “trap nests” in Toronto to allow them to observe the behaviour of different bee species. The bees they looked at usually build nests in cavities above the ground, and depending on the species, they construct them out of various natural materials such as leaves, mud, and even small pebbles. But as the bees got on with their work, the researchers noticed a few more modern materials making their way into the nests. “It was during inspection of the nesting tubes we discovered non-natural materials built into the nests of two different bee species,” they said.

The bees opted for types of plastic that mimicked the natural materials they’d usually use. The alfalfa leafcutter bee (Megachile rotundata), which as its name suggests usually collects leaves, supplemented some of its nests with bits of glossy white plastic bag—in the nests where it was used, the plastic replaced about 23 percent of the leaves.

Meanwhile, the Megachile campanula, which usually collects pine resin, occasionally replaced that with polyurethane-based sealants, the like of which are used on building exteriors.

Of course, the bees could have incidentally collected the plastic when searching for their usual nesting materials. But the researchers also considered the opportunity that they'd adapted to include manmade materials in their inventory of nesting stuffs. For the leafcutter bee, they found markings on the plastic materials that showed it chewed them differently to leaves. It also returned to leaf material after using a few bag fragments, which suggested leaf availability wasn’t a limiting factor.

In both cases, bee larvae in the nests matured healthily. That's not to say plastic is a suitable building tool: the plastic bags, for instance, didn’t stick together like leaves, as usually the bees would create a kind of adhesive by chewing the juicy plant material. Previous studies regarding other animals have also shown that plastic in nests can cause mould to grow, or can kill them by preventing them from moving or breathing as usual. We are most definitely poisoning the planet with our plastic waste.

But in other ways, for bees at least, plastic could potentially have advantages over natural materials, and not just because it’s more easily available in urban environments. The study authors explained that plastic might physically impede parasites form infecting those in the nest; in this case, all the bees emerged parasite-free.

Whether the bees knew what they were doing when they picked up plastic for their nests, it's an interesting reminder of quite how adaptive different species can be—or have to be, even—when they’re up against our bad habits. The study even suggested that those species that adapt to increasingly plastic environments might have an advantage in urban areas over those that don’t: "Although perhaps incidentally collected, the novel use of plastics in the nests of bees could reflect ecologically adaptive traits necessary for survival in an increasingly human-dominated environment."