Farm­land bees face sea­sonal nec­tar famines

Early spring and late sum­mer are lean times for the pol­li­na­tors, finds new re­search.

BBC Wildlife Magazine - - Wild News -

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

Bum­ble­bees, such as the buff-tailed, rely on earlyand late-flow­er­ing plants, in­clud­ing clover.

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