Insects and That
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Insects and That

Are hybrid bees an inevitable result of modern pollination?

Two bumblebees mating on green leaves
Photo: Done Horne/ Wikimedia Commons

There’s much to be concerned about in the world of pollination, and a lot tends to centre on the impact of commercially-produced bees, namely honeybees and bumblebees.

Backed by a growing body of research, they have been accused of outcompeting native pollinators by their sheer abundance, spreading diseases, and simply not being able to meet the global shortfall in pollination services. But are commercial bees also messing up the genetics of their wild cousins?

Logically, there’s a risk. Commercial bumblebee colonies, reared to boost crop pollination, are generally Bombus terrestris — one of the most commonly-found species in the wild. But the commercial kind are generally reared in different geographic locations to the countries they’re put to work in, meaning genetic differences are almost inevitable.

Breeding between bees of the same species but from different places can have both positive and negative effects, so keeping an eye on what’s going on seems a worthwhile endeavour.

Absence of evidence

In a Swedish study, scientists analysed whole genomes from wild and commercial bees, both in areas with a history of importing commercial bees and those without. In what is likely to have been the highest-resolution genetic analysis of its kind to date, there was little evidence of introduction of new genetic material into local populations.

There were, however, plenty of divergences between wild and commercial bees. Perhaps most interestingly, chromosome 11 of the commercial bees seems to most notably set the two groups apart; an area associated with both flight and immune response to pathogens.

It’s important to note that the scientists certainly don’t rule out the possibility of wild-commercial hybrids occurring — simply that it’s not happening in the samples they analysed. Commercial bumblebees were observed foraging near wild bee nests, and wild bees were even found within commercial colonies. The conditions seem to be there for hybridisation to happen, although that would require queens and drones from colonies to get out and about, not just workers.

Close-up of the face of a bumblebee on a flower
Photo: Abejorro/Flickr

Hybrid theory and practice

As is often the case in cutting-edge field research, this work is likely to result in further, similar, efforts elsewhere. This should paint a clearer picture of to what extent, if any, commercial-wild bumblebee hybrids are occurring; and if they are found to be, the effects of their presence. Will they outcompete non-hybrids, will they effect the overall fitness of wild populations to thrive, or will the effects be surprising, welcome or not?

It’s fairly easy to view commercial interventions in plant-insect interactions as innately a bad idea — but ultimately that’s not the sharpest thinking. Demand for crops to be pollinated isn’t going to go away, and neither is that for crop pests to be moderated through non-pesticide means. Wild insect populations are in decline at worst, or stretched and stressed at best. Climate change isn’t going to stop messing with the dynamics of all the above, either.

Human intervention in the midst of an ecological mess considerably of our own making is happening — and can yield good results when handled appropriately. This latest work only serves to underline the need for care when introducing insects into ecosystems for pragmatic purposes, as well as a continued appetite for rigorous monitoring of the side-effects of such introductions.

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Gary Hartley

Gary Hartley

Writer of different things. Come for the insects, stay for the odd literary works, or vice versa. @garyfromleeds https://medium.com/insectsandthat