Before dawn, with enough light to see, James Dorey and his companions went out to find bees.
This may sound like a futile exercise, since most bees sleep rather than forage for food when it’s dark; dim light blurs the colors of the flowers, and the nights result in cooler temperatures.
But at least some bees have bucked the trend. For the first time, Dorey and her team based in Adelaide caught a bee foraging at night in Australia, and it shows that there are more nocturnal bees hiding in the dark.
“We know that bees mostly forage during warm weather – they generally don’t like foraging when it’s cold, wet, dark, too hot,” Dorey, an entomologist at Flinders University, told ScienceAlert.
“Hence, we bee researchers tend to follow a similar work ethic.”
We know that some bees are nocturnal, having evolved to these conditions. So unless scientists search for it in the dark, that means we could potentially miss out on an entire species of night bee.
“It was long thought that some bees might forage at night in Australia, but this is based on fairly indirect data,” Dorey told ScienceAlert.
“Foraging behavior like this has evolved several times [around the world] and some groups of bees have species that at least extend their foraging into the dark, even if they are not foraging in the dark as a full-time show. “
Dorey’s outing to Daintree rainforest – as well as a number of other research sites around far North Queensland – eventually proved useful, with the team reporting foraging for the evening meal of two native bee species: Reepenia bituberculata and Meroglossa gemmata, the latter a kind of masked bee.
This is the first time an Australian bee has been recorded foraging in the dark, and it makes Australia the only place with known low light adaptations. masked bee In the world.
The team goes a step further, learnsClose-up images of 75 specimens from 68 bee species, analyzing characteristics such as eye, head and body type and size – all to determine whether the night bee is undergoing physical changes compared to the bee foraging during the day.
Bees, like most insects, have both compound eyes (those on the side of their heads) and simple or Ocelli’s eyes (three small eyes in the center of the head), which only catch light. Both compound eyes and ocelli are larger in bees that forage in dim light.
“We found that these low light-adapted bees tended to have bigger eyes, as well as being on the larger side for bees,” Dorey told ScienceAlert.
(Dorey et al., Journal of Hymenoptera Research, 2020)
Above: Low light bees, facultative (can forage in both low light and normal light), and diurnal (daytime) bees that show different eye sizes of the ocelli. A and B are Reepenia bituberculata, while E is Meroglossa gemmata.
Big eyes make sense – the bigger your eyes are, the more light you can take in – and researchers suggest that larger bodies could help night bees better regulate their temperature in colder conditions.
The team hopes that the image analysis technique can be used in the future to find other species of night bees, without having to sneak around in the dark hoping to find them.
“We were able to show that it is possible to determine whether a bee can adapt to dim light conditions using only imagery,” Dorey told ScienceAlert.
“It will make it easier for researchers to find these neat, dim light bees in the future.”
With limited research investigating even Australia’s daytime (or diurnal) bee populations, there is still a lot of research to be done – including how these creatures can adapt to a warming future, and it is critical that night bees are not left out.
“It is possible that these bees will be threatened by climate change,” said Dorey ScienceAlert.
“But it’s also possible they will benefit from a warmer climate increasing their area or allowing them to forage for longer periods of time. If the latter is true, then these bees may become more important for pollination services as a diurnal foraging window for bees. become narrower. “
This research has been published in Hymenoptera Research Journal.