After a break for tea and biscuits I went to the second lecture of Monday afternoon: John Hendrie on Senses of the Honeybee. This was an interesting subject and well presented and I took copious notes. Let’s see how well I can read them.
The Senses: Taste, Smell, Touch, Hearing, Sight, Gravity, Time, all go through the nervous system: brain and ganglia through thorax and abdomen. John displayed a picture of the mouthparts from Dade’s book. Taste is mainly for sugar concentration.
Sight. 2 compound eyes, 3 ocelli. Drones’eyes are much bigger, meeting at the top of the head and pushing the ocelli forward. Vision. The queen has around 3,500 ommatidia (lenses) in her compound eyes, workers 5,500 and drones 10,000. Each lens has 8 segments each of which is sensitive to a different wavelength. Resolution is about 100 times worse than human vision. Flicker frequency about 200 – 300 ( 6 – 10 times faster than us) and therefore they are good at seeing lights flashing off and on. Bees see polarised light, giving the sky a pattern of shades of grey, which helps them navigate.
Colour vision was investigated by Von Frisch back in 1914. They see about 70 colours ranging from ultra-violet to orange in the range of 300 – 650 illegibles whereas people see colours in the range 370 – 750 illegibles. The nectar guides in flowers often show up as ultra-violet lines which bees can see but we can’t.
They can do pattern and landmark recognition and can tell left and right, so it’s ok to put hives in pairs but not triples. They can learn what flowers look and smell like.
The ocelli each have about 800 receptor cells. They can detect changes in light intensity but can’t focus light. They help with navigation and flight stability. Peak sensitivity is to green and UV light. They are covered in hairs for protection.
Antennae have lots of organs described as plates, pits, flakes, domes and hairs of various lengths. Between them they are sensitive to smell, taste, CO2, temperature, movement and alignment. The Johnston’s organ acts as an air-speed indicator in flight. The worker’s antennae have 10 segments but the drones (men being more sensitive than ladies) have 11.
Sound. Bees have no ‘ears’ but their legs respond to the vibration caused by bees dancing on the comb. Both queens and workers respond to queen piping, again probably through comb vibration, not as we hear it.
Gravity is useful in the darkness of the hive for interpreting the meaning and direction of the waggle dance. Hair plates are the organs they use for this.
Sting sense organs are mechano-receptors that detect the distribution of the lancets when the sting is in use so the barbs alternate.
Time. Bees can be trained to 24 hours cycles only, so they return to the same flower source at the same time each day. They can have several sources which yield nectar at different times of day.
Hormones are important in bee development. The juvenile hormones produced in the larval stages ensure they are fed properly by their big sisters. Queen larvae give different hormones so they are fed differently with more sugar but less protein than workers: royal jelly vs worker jelly.
There’s more but I can’t read it. I may have mis-read some of what I have written above, so feel free to correct me in you know better. I know that one or two people were recording lectures on their portable telephones but I don’t know how to do that.