Greater pollinator: the humble bumblebee has every right to brag

Honeybees are often feted as the great pollinators, but recent studies show their hairy cousins, which are better adapted to our climate, do most of the work

Thu, Jun 12, 2014, 01:00

Perfectly formed tomatoes and strawberries in supermarkets owe their shape to one surprising natural additive – bumblebees. Without them buzzing around, these fruits can fail to set or may grow misshapen. So important are bees that growers in northern Europe now routinely add commercially produced boxed bumblebees to their glasshouses.

John Foley grows tomatoes in Rush, north Co Dublin. His family nursery produces 18 million tomatoes each year under glass for the Irish market. His father first built a glasshouse here in 1936. Foley recalls how as a boy he used a little motor and stick device to vibrate tomato trusses and pollinate the flowers. “To physically do that job today you would need a crew of six people to do the whole nursery, every day,” he says.

Instead, the yellow flowers of the 10 varieties of tomatoes in his family’s Kilbush Nurseries are now pollinated naturally by bees produced in a Slovakian bumblebee factory. Every two weeks or so, small nest boxes of white-tailed bumblebees, Bombus terrestris, arrive with a queen bee and 60 or so workers. Foley opens the box and they go about their business collecting pollen and setting fruit.

 

A neat trick

Bumblebees are the expert pollinators for crops such as strawberries, tomatoes and field beans because of their buzz. “Bumblebees have this neat little trick called buzz pollination. This is where they vibrate their wing muscles at a particular frequency and they create a cloud of pollen that jumps off a plant,” says bee expert Dr Tomás Murray of the National Biodiversity Data Centre.

“Bee hairs are negatively charged and the positively charged pollen grains stick to them, so it is a great way for them to get loads of pollen rapidly from flowers. But for people who own tomatoes, strawberries and apples, it is also the most efficient way of pollination.”

Often honeybees are feted as the great pollinators of our crops and wild plants, but recent studies show bumblebees do most of the work. “It seems wild bees contribute far more to pollination that we previously acknowledged,” says Murray. And bumblebees are becoming more important due to the calamity facing wild honeybees in Europe and North America.

“If you go to a part of Ireland where there are no beekeepers, you won’t see a honeybee. That is definitive now,” says Dr Murray.

What are the differences between honeybees and bumblebees? Horses for courses. Honeybees, with up to 80,000 workers in a hive in summer, specialise in pollinating mass flowering crops, and are especially good at tackling oilseed rape fields, almond groves and large apple orchards. “They have been introduced in many countries around the globe and can pollinate a whole variety of different plants they haven’t evolved for,” he says.

The Irish climate arguably suits their bumblebee brethren better. While honeybees probably originated in Africa or the Middle East and then spread out, bumblebees originally evolved in Mongolia. “They are big, hairy, temperate creatures, so they are well adapted to rough conditions. They forage much earlier in the day and much later at night, at lower temperatures and even in light rain, whereas honeybees won’t,” Murray explains. “We are the island of the bumblebee.”

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