Plight of the bumblebee: how Queen Mary helped Britain’s native pollinators
A foreign subspecies of bumblebee, imported as part of a billion-dollar global trade in pollinators, was found by researchers at Queen Mary’s School of Biological and Chemical Sciences to pose a risk to the UK’s native species Bombus terrestris audax. As a result, the use of non-native pollinators is now licensed in the UK, with fines and custodial sentences levied against their uncontrolled use.
Pollinators play a central role in our food chain and in global agriculture: the value of bumblebee-pollinated tomato plants alone was estimated at €12b in 2004.
There’s an extensive international trade in bumblebees as pollinators for a wide range of glasshouse and other crops, from strawberries to peppers, and cranberries to plum trees. In the UK alone, by 2014, 40,000-50,000 colonies of commercially-reared foreign bumblebee colonies were imported annually.
While much ecological research has focused on the effect of invasive species on the environment, little attention has been paid to the impact of non-native pollinator subspecies. In the face of a global decline in the number of pollinators, this question is more pressing than ever.
Professor Lars Chittka’s study examined the effects of this massive influx. Could these imports of a foreign subspecies of Bombus terrestris to the UK endanger native bumblebees?
The value of bumblebee-pollinated tomato plants alone was estimated at €12b in 2004
How did they do it?
The team studied whether the arrival of commercially reared subspecies of Bombus terrestris could threaten native bumblebees through competitive displacement, hybridization between native and non-native pollinators, or the inability of native species to cope with newly imported parasites.
The studies, performed between 2003 and 2006 by Professor Chittka and various team members, (most notably PhD student Tom Ings, who was funded by a Queen Mary PhD studentship), made a direct ecological comparison between commercially imported and native B. terrestris colonies.
In particular, they compared the nectar-foraging performance and numbers of offspring of commercial and native colonies growing under identical field conditions.
What did they find?
Non-native colonies performed exceptionally well under UK field conditions, with substantially higher nectar foraging rates than native colonies. Non-native colonies produced more new queens, while native queens also didn’t mate selectively with members of their own population, increasing the risk of introgression, the movement of genes from one population into another.
The high reproductive success of commercial colonies demonstrated the substantial risk that these colonies could grow and spread across the UK; the arrivals’ superior foraging ability and large colony size meant they could out-compete native bumblebees. Professor Chittka’s studies showed that the invasive potential of non-native subspecies of otherwise helpful organisms shouldn’t be overlooked.
Such was the significance of these findings that the team recommended immediate precautions: native species and subspecies should be locally reared and the use or disposal of bees should be strictly regulated.
The high reproductive success of commercial colonies demonstrated the substantial risk that these colonies could grow and spread across the UK
Transforming bumblebees’ future
Professor Chittka’s studies have had a considerable effect on the UK environment. This work resulted in a review of Defra’s policy, the introduction by Natural England of mandatory licensing for the use of non-native pollinators, and legal changes that carry a fine of up £5,000 or a six-month custodial sentence for the uncontrolled use of such pollinators. As a result, all major commercial providers of pollinators now sell a UK native subspecies of bumblebee, Bombus terrestris audax.
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We study and teach the psychology of humans and animals: its evolution, its mechanisms, its failures (psychopathology) and its triumphs (well-being). We emphasise an interdisciplinary approach, focused at the interface between psychology (perception, cognition, communication and social life) and biology (genomics, neuroscience, ethology and evolution).