Urban Bees Respond to Littering by Adopting Innovative Nest-Building Techniques


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As you probably know, being 'busy as a bee', is not just an empty metaphor. From searching for nectar and pollen to tending to honeycombs, bees are amongst the hardest workers out there. So it should come as no surprise that two species of urban leafcutter bees in Canada, have learnt to adapt to our increasingly polluted world, by using small pieces of plastic found in the litter, to build their nests.

Scott Maclvor and Andrew Moore from the University of Guelph in Ontario, Canada stumbled upon these resourceful bees whilst examining artificial nest boxes of the Megachile campanulae and Megachile rotundata species, in the city of Toronto.These are not typical honey bees that live in colonies, but a solitary species that dwells on its own.

In order to build their nest, the females seek out a small cozy place - anything from a hole in a tree to even an opening in a plant stem. They then lay one egg, tuck in a little ball of food for when it hatches, and cordon off the area into a tiny brood cell, before beginning work on the next.

The bees go through this painstaking process for each egg to ensure that the baby bees can survive on their own. That's because the adults have a very short lifespan and are not around to see the eggs hatch.

It was inside the nest of one of these, the Megachile campanulae bees, that researchers found evidence of a gray sticky substance. Initially, MacIvor thought that the goo was chewing gum because it did not resemble the plant resin that the bees typically use to construct their nests.

But a detailed examination with a scanning electron microscope as well as an x-ray microanalysis, confirmed that the bees were using a polyurethane-based sealant, a plastic material found at construction sites, to build the brood cells.

Similarly, the Megachile rotundata bees used pieces of polyethylene-based plastic bags, the kind you would find at your local grocery store, for their brood cells. In both cases, the use was extensive - with as many as a quarter of the leaves replaced, by plastic.

What was even more interesting is that the insects had not been forced to pick plastic because of lack of leaves. In fact, the researchers believe that from the way they had chewed and spat it out, the bees had deliberately gone seeking for the man-made material. Additionally, the marks on the plastic were different from those on the leaves, providing further proof that the bees had known exactly what they were biting into.

The best news is that while for most land and marine creatures, plastic bags and other forms of litter prove to be harmful, such is not the case here. According to MacIvor and Moore, larvae have successfully developed from the plastic nests. And better yet, no parasites were found in the larvae, suggesting that the man-made material is more effective at blocking them than leaves and plant resins. Furthermore, MacIvor and Moore say that the nests constructed from plastic seem to be sturdier than those made from only natural materials. All this may explain why the smart bees are now deliberately seeking out the plastic!

In order to continue monitoring this interesting development, the researchers are keeping tabs on over 200 artificial nest boxes located in backyards, gardens, parks, and green roofs all across Toronto and the surrounding areas. Who knows what the busy bees will think up of next!

Resources: beforeitsnews.com,slate.com, dailynews.co.uk,Guelphnow.com

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