Too much sugar in nectar slows down bumblebees as it takes them longer to vomit it back up4 min read

0
18

Too much sugar in nectar slows down bumblebees as it takes them longer to vomit it back up for use by other in the colony, a study has found. 

Bumblebees drink nectar from flowers, then ferry it back to their nest where they offload it — by vomiting — for use by other bees in the colony.

Sugar in nectar makes it appealing — and the more sugar within the nectar, the more energy it contains. However, nectar also gets thicker as its sugar content increases.

This makes it more difficult for bees to drink and regurgitate — taking more time and energy, researchers explained.

Bees therefore seek nectar that is sugary enough to provide the most energy without tipping the balance into a liquid that is troublesome to collect and regurgitate.

The findings could help develop flowers with the most appealing nectar to help improve crop pollination and yields. 

Too much sugar in nectar slows down bumblebees as it takes them longer to vomit it back up for use by other in the colony, a study has found

Too much sugar in nectar slows down bumblebees as it takes them longer to vomit it back up for use by other in the colony, a study has found

In their study, zoologist Jonathan Pattrick of the University of Oxford and colleagues looked at the mechanics of both nectar drinking and regurgitation.

Check this out  Car makers to leave the handbrakes off in future and all switch to electronic devices

They focused on one of the UK’s most common bumblebee species — Bombus terrestris, or the buff-tailed bumblebee.

The team found that nectar that is low in sugar is both easier for bees to drink and then to subsequently vomit back up.

As nectar gets more sugary, it takes bees longer to drink — but considerably more  difficult for them to regurgitate the liquid.

‘Bumblebees must strike a balance between choosing a nectar that is energy-rich, but isn’t too time-consuming to drink and offload,’ Dr Pattrick said.

‘Nectar sugar concentration affects the speed of the bees’ foraging trips, so it influences their foraging decisions.’

According to the researchers, it has long been known that nectar with a higher sugar concentration takes bees longer to drink.

However, the impact of increasing sugar levels on nectar regurgitation had remained largely unexplored.

The team hope their findings will help other researchers make better predictions about which types of nectar bumblebees and other pollinators should like the best — and, by extension, the flowers and plants that they are most likely to visit.

This could then help agricultural breeders to produce more appealing flowers for better crop pollination and higher yields.

In their experiments, bees were allowed to forage on sugar solutions ¿ of three different concentrations ¿ in the University of Cambridge's Bee Lab

In their experiments, bees were allowed to forage on sugar solutions — of three different concentrations — in the University of Cambridge’s Bee Lab

The solutions were made available atop a set of scales (pictured), allowing the researchers to weigh the bees and also time how long it took them to drink nectar

The solutions were made available atop a set of scales, allowing the researchers to weigh the bees and also time how long it took them to drink nectar (picture)

The solutions were made available atop a set of scales (left), allowing the researchers to weigh the bees and also time how long it took them to drink nectar (right)

In their experiments, bees were allowed to forage on sugar solutions — of three different concentrations — in the University of Cambridge’s Bee Lab.

The solutions were made available atop a set of scales, allowing the researchers to weigh the bees and also time how long it took them to drink nectar.

When the flying insects returned to their ‘nest’, the researchers then timed how long it took for them to vomit up the collected nectar.

‘For low strength nectar, bees had a quick vomit that only lasted a few seconds, then were back out and foraging again,’ said Dr Pattrick.

‘But for really thick nectar they took ages to vomit, sometimes straining for nearly a minute.’

'For low strength nectar, bees had a quick vomit that only lasted a few seconds, then were back out and foraging again,' said Dr Pattrick. 'But for really thick nectar they took ages to vomit, sometimes straining for nearly a minute'

‘For low strength nectar, bees had a quick vomit that only lasted a few seconds, then were back out and foraging again,’ said Dr Pattrick. ‘But for really thick nectar they took ages to vomit, sometimes straining for nearly a minute’

The perfect nectar sugar concentration for the highest energy intake depends on the species drinking it, however, because different species feed in different ways, the researchers said

The perfect nectar sugar concentration for the highest energy intake depends on the species drinking it, however, because different species feed in different ways, the researchers said

For any given nectar concentration, bees regurgitate the nectar quicker than they initially drink it.

‘It’s hard to drink a thick, sticky liquid, but imagine trying to spit it out again through a straw — that would be even harder,’ explained Dr Pattrick.

‘At a certain sugar concentration, the energy gain versus energy loss is optimised for nectar feeders.’

The perfect nectar sugar concentration for the highest energy intake depends on the species drinking it, however, because different species feed in different ways, the researchers explained.

The full findings of the study were published in the Journal of the Royal Society Interface.