Scientists in Argentina have discovered a wild bee’s nest made entirely out of plastic. The research, published in the journal Apidologie, provides the first documented evidence of this phenomenon.
From 2017 to 2018, Mariana Allasino of the National Agricultural Technology Institute in Argentina and her colleagues were studying the pollinators of chicory in San Juan, Argentina. As part of their research they put out 63 trap nests made of wood with cavities where bees can construct brood cells within which the next generation of bees develop.
The research team checked the trap nests each month. Only 3 were used by wild bees, 2 of which contained brood cells of Megachile jenseni, constructed out of petals and mud.
The other nest was made entirely out of plastic. The plastic used consisted of thin, blue strips, as well as white pieces that were a bit thicker. The sections of plastic, which were similar in size and shape to a fingernail, had been carefully cut by bees and used as a lining for the nest. Researchers think the plastic may have come from a plastic bag with a similar texture to the leaves that leafcutter bees typically use to construct their nests.
In the nest made of plastic one brood cell was unfinished, one cell contained a dead larva, while the other was empty, leading the researchers to believe it may have contained an unidentified adult that survived to emerge as an adult bee.
Although we don’t know for sure which species built this nest, the team says it may have been Megachile rotundata, also known as the Alfafa Leafcutter Bee. There are previous reports of this species incorporating plastic in to their nest lining, although previously plastic formed was used alongside natural materials.
It is thought that plastic pieces could be causing harm to the bees that use them for nest construction. Theresa Pitts-Singer at the US Department of Agriculture suspects the effects are not entirely beneficial. “I find it rather sad, but interesting. It begs for a choice-test in an enclosure to determine why this plastic might be more appealing or adaptive than use of natural materials”. She highlighted the need to determine whether plastic lining in brood cells can harm bees. Plastic traps more moisture that natural materials, which may lead to higher pathogen levels. Plastic may also become toxic as it breaks down.
The authors acknowledge that more research needs to be undertaken to understand the potential impact of plastic on bees, but also draw attention to how the observed behaviour demonstrates the adaptability of bees to human disturbance and changing environments.
Allasino, M. L. (2019). Scientific note: first global report of a bee nest built only with plastic. Apiodologie, 50: 230-233.