Sajesh VijayanAug 10, 2023

๐˜ˆ๐˜ฑ๐˜ช๐˜ด ๐˜ฅ๐˜ฐ๐˜ณ๐˜ด๐˜ข๐˜ต๐˜ข is a honeybee that can forage at night when the moon is at least half-full. But can they see colour at night? We explored this in our paper, out now in @RSocPublishing
https://doi.org/10.1098/rspb.2023.1267
Here is a short explainer of what we found ๐Ÿงต 1/8

#Honeybees #ColourVision #VisualEcology #Ecology #AnimalBehaviour #Foraging

Show threadSajesh Vijayan
We tested ๐˜ˆ. ๐˜ฅ๐˜ฐ๐˜ณ๐˜ด๐˜ข๐˜ต๐˜ข workers in open conditions where the ambient light was equivalent to 1) half-moon, 2) brighter than half-moon and 3) dimmer than half-moon. In dim light conditions, we trained bees to a blue feeder containing sugar solution, and then tested them on empty feeders that were either blue or grey of varying intensities. If the bees can learn and detect colour at low light levels, they would choose the blue stimulus 2/8
Aug 10, 2023 at 9:29amWeb
Show threadSajesh VijayanAug 10, 2023
In the brighter light conditions (half-moon equivalent and above), most of the bees visited the blue stimulus first. At the dimmest condition, only around half of the bees visited the blue stimulus first. 3/8
Show threadSajesh VijayanAug 10, 2023
When the total visits in a trial were considered, approx. 80% of the visits made by a bee were to the blue stimulus till half-moon light intensities. The total number of visits and the visits to blue were both low at the dimmest light level. 4/8
Show threadSajesh VijayanAug 10, 2023
This shows that the bees detect the blue stimulus at night. What if it is using the brightness information, and not colour? To explore this, we modelled the stimuli to understand how a bee might perceive it in its visual system. Using three representative light conditions (daylight, twilight and moonlight), and information from the visual system of the Western honeybee ๐˜ˆ๐˜ฑ๐˜ช๐˜ด ๐˜ฎ๐˜ฆ๐˜ญ๐˜ญ๐˜ช๐˜ง๐˜ฆ๐˜ณ๐˜ข, we modelled the stimuli in the honeybee visual system. 5/8
Show threadSajesh VijayanAug 10, 2023
If the visual system of the bees can detect colour in dim light, the blue stimulus appears as blue in all three conditions. On the other hand, if the visual system can detect only brightness, the relative intensities of the stimuli vary a lot, and becomes an unreliable cue. 6/8
Show threadSajesh VijayanAug 10, 2023
Our results show that the giant honeybee can indeed see colour at night!!! This is the first report of a honeybee, which has daylight-suitable apposition optics, being capable of seeing colour in dimly-lit conditions. The precise mechanims by which the bees achieve this is unknown, and their anatomy alone does not explain this. Future studies must explore neural summation occurs in their visual system, which will improve signal-to-noise ratio. 7/8
Show threadSajesh VijayanAug 10, 2023
Huge shout-out to the spectacular group of people I was lucky to work with: Hema Somanathan (@BEElab_iisertvm) , Eric Warrant and Almut Kelber (Lund Vision Group), Balamurali GS and Jewel Johnson 8/8