Bees waking up earlier due to climate change could affect pollination, study says

The majority of the bee species in the UK are solitary, and will lay eggs in the summer

Wild bees are waking up earlier than usual in the year and this is affecting the pollination of crops like apples and pears, according to a new study.

The research found that for every degree Celsius rise in temperature caused by climate change, wild bees, including bumblebees, are emerging six and a half days earlier on average from their nests.

Scientists say that by leaving their nest early the bees are out of sync with the plants they collect pollen from.

The study, published in the scientific journal Ecology and Evolution, is thought to be the largest of its kind.

Do bees go to sleep when it's cold?

There are more than 250 types of wild bees all with different life cycles and ways to overwinter or hibernate.

For bumblebee species, the queens will hibernate generally underground before emerging from hibernation in the spring and laying eggs.

The majority of the bee species in the UK are solitary, and will lay eggs in the summer, which hatch and develop into adults in autumn. These adults then hibernate in a cocoon until they emerge in the spring.

How might pollination be affected?

Waking up often refers to the first emergence of individuals in the spring from cells that were made the year before and have overwintered.

The study examined 88 different species of wild bees over a period of 40 years using different recordings.

The figures showed different species emerge at different times but on average, the 88 species are emerging four days earlier per decade.

Chris Wyver, co-author of the study from the University of Reading, said: "Warmer conditions mean bees emerge from hibernation earlier, but there may not be enough food to provide energy for them when they start buzzing about.

"Matching wake-up dates with plant flowering is vital for newly emerged bees because they need to find pollen and nectar to increase their chances of survival and produce offspring.

"A mismatch means bees cannot pollinate effectively."

Which plants could suffer?

Dr Wyver suggested a reduction in natural pollination might mean more farmers needing to use managed honeybees for pollination, which could create greater costs.

The study says that with winters projected to be between 1 and 4.5°C warmer and up to 30% wetter by 2070, according to the Met Office, spring is likely to continue to start earlier and bees will continue to become active earlier in the year.

The trend could have a big impact on plants that depend heavily on pollination, such as apple trees, which might not be ready to flower by the time the bees emerge.