Farmland bees face seasonal nectar famines
Early spring and late summer are lean times for the pollinators, finds new research.
Britain’s pollinators are under wellpublicised pressure from pesticides and parasites. But, according to new research, they are facing an additional problem – they are going hungry during certain months of the year.
“There aren’t as many flowers in the countryside as there used to be,” says Jane Memmott of the University of Bristol. “About a third of nectar in rural areas has been lost since the intensification of agriculture in the 1950s.” But, she says, it’s not just the amount of nectar that matters, but what time of year it’s available.
Working in south-west England and focusing on bumblebees, Memmott’s team found two peaks in nectar production – in May and July. In March, June and much of August and September, though, nectar availability falls short of their requirements.
“You can end up with a feast and famine situation, and the vast majority of pollinators do not have food reserves, so they are not very good at coping with famines,” says Memmott. “If a bumblebee queen comes out of hibernation in March and finds nothing to eat, it doesn’t matter how
much nectar there is in summer, because she won’t be alive.” The team found that just three species of wildflower – ramson, creeping thistle and white clover – provided 50 per cent of all nectar. Wildflower strips at the edge of fields help to provide floral diversity on agricultural land. But, even then, they tend to flower in late spring and early summer when nectar and pollen are already found in abundance. The biologists recommend that more attention be paid to the flowering times of farmland flora. “Early-flowering plants [such as] willows and dandelions ( left), or late-flowering red clover and ivy could all help to fill the hungry gaps” says Memmott’s colleague, Tom Timberlake.
Memmott is particularly enthusiastic about willows, which produce large volumes of nectar and pollen and have varied flowering times. And, being trees, they also require little attention and have a long lifespan. Stuart Blackman FIND OUT MORE Journal of Applied Ecology: bit.ly/nectargaps