The Wax Makers.

Introduction.

After unseasonably warm weather, we had a nice crisp frost the other night and the air is chilly. At least it was yesterday when I cycled over to Cawdor to watch thousands of greylag geese and a couple of hundred whooper swans feeding on fallen grain in a stubble field. I’d heard the whoopers trumpeting on my return from a walk to the wild bee tree (which has been continuously occupied since 2019). On looking in the direction of the sound, I saw in the distance large white objects that looked to the naked eye like sheep. They weren’t though, and, through my binoculars, I later made out lots of swans among the geese. How exciting was that! The field was almost covered in geese, and, every time something disturbed them the noise was deafening, even from half a mile away.

I was careful not to alarm the birds on my visit, and my stealthy approach enabled me to get fairly close to observe the swans’ behaviour. I got some photographs but they are not perfect. I was still too far away. Whooper swans are smaller than I’d expected and this was my closest encounter to date. There were some juveniles with greyish plumage. Some kept close to their mothers, but I noticed a small group of teenagers hanging out together in a huddle and flexing their wings. The swans were relaxed and some were resting with one back leg stretched out displaying their large black webbed feet. Some were lying down and others grazing to get some strength back before the next leg of the long journey from Iceland to England. Next day the whoopers had moved on south and the geese were in another field.  

Chilled Bees.

One morning, when I opened the curtains, I found an immobile bee clinging onto the patio door. I brought her inside for some breakfast and in a short time she was ready to head home again.

This bee was not so lucky though and remained terminally immobile. I removed the dull yellow pollen load for testing thinking it must surely be ivy pollen and my job would be easy. I already have an ivy slide for reference. Little did I know when I got out my kit that I would spend most of the day trying to work out what flower it came from. It is not ivy, viburnum, mahonia, or nasturtium which are all flowering this week. Expert pollen “detective” Christine Coulsting is on the case helping me and I hope to get an answer soon. Meanwhile, I’m collecting all the flowers I find blooming and adding them to my collection of pollen slides. I’ve even tidied out my boxes of microscopy kit.

I use this site to help me identify pollen; https://www.paldat.org/search/C

Using the Stove.

Having the stove on all day means I can warm the slides on top of it. I’ve even experimented with cooking baked potatoes inside it. You could try this if you have a wood-burning stove as it saves electricity and is very satisfying. My neighbour and friend Juliet told me about cast iron potato holders that you can get online. The reviews are not great so I worked out how to cook them without buying kit, incinerating them, or having thick layers of charcoal on the potato. I found some flat stones and lined an old cake tin to keep some distance between the metal and potato. My first attempts without stones produced too much burnt spud. I let the logs burn down to embers and flattened out one side and lay the tray with foil-wrapped spuds on top for ¾ to one hour depending on potato size.

Wax Making.

I’m sure the recent warm weather (15°C) means the queens are still laying. I’ve found clear wax flakes on the varroa boards. They look a bit like sea salt flakes. Have you ever wondered how the bees make them?

Current requirement for new comb drives production in a honey bee colony. It is costly to make in terms of energy and bee power. Roughly 8lbs honey are needed to make just one pound of wax, and 66,000 bee hours are needed to produce 77,000 cells which can be made from 1kg/2.2lbs wax¹. Removing each scale from the wax plates and manipulating it takes 4 minutes, and a fairly constant temperature of 35°C is needed to keep wax secretion going and the flakes pliable enough for easy manipulation.

Wax Glands.

A worker bee has 4 pairs of wax glands on her underside or ventral surface. They are situated on the ventral plates, or sternites, of the 4^th to 7^th abdominal segments. They cannot normally be seen unless the gland is active in which case a scale may be seen protruding between the sternites. If one sternite is removed then two large, oval, pale yellow areas of cuticle can be seen². These plates are called the wax mirrors and they cover the wax gland system which is made up of three types of cells called specialised glandular epithelial cells, fat body cells, and oenocytes. The latter are very large cells found in various parts of the bee body and are primarily involved with the secretion of lipoproteins.

Wax is secreted through the cuticle or outer cover of these plates/mirrors rather like paste from a tube. Liquid wax globules join together to form a thin layer becoming the scales that we can recognise. They are very thin and range from 200-500 µm though even thinner ones have been recorded. If you look closely at the photographs, you will notice a difference in thickness of scales. The photograph of the bee outside the hive is rather unusual because this work normally takes place inside the hive where an even temperature can be maintained. The wax has hardened and will be more difficult for the bees to manipulate.

If you study the photograph of the observation hive above you will see festooning behaviour where the bees have joined together like a necklace. This is one strategy to enable a constant temperature to be maintained.

Who Makes Wax?

Who does the comb construction? The nest bees that have finished working in the central brood nest are tasked with building comb. They are aged between 10 and 20 days old and have finished feeding brood. Their hypopharyngeal glands are no longer secreting brood food but the enzymes needed for making wax and honey are reaching their peak so the timing is perfect. The wax gland system is triggered into action by a nectar flow and a shortage of storing space.

When a colony swarms and moves to a new home it favours a site that has previously been occupied since all they have to do is clean up and refurbish the old comb and make some new comb only if needed. If starting nest building from scratch it will take much longer to get the job done and enough resources stored for winter so it is easy to understand why only 20% swarms survive their first winter in the wild.

Gravity and Comb Orientation.

Have you ever wondered how a colony of honey bees can carry on comb building correctly when its hive is knocked over on its side? A honey bee has a complex nervous system and it can detect gravity using specialised mechanoreceptor hairs called hair plates situated in various parts of the body including legs, antennae, abdomen, and neck. The neck hairs situated between the head and the thorax are key to how comb cells are built in the correct orientation and slightly tilted back to prevent honey leaking out. Hair plates are also involved with communication and help the bees signal direction during waggle dances through using gravity in relation to the sun’s orientation and direction of forage source.

Comb Construction in Outer Space.

Quite remarkably, honey bees can build comb in outer space where there is no gravity. Scientists studied comb building in a small colony taken up to space with the 1984 Challenger mission³. They discovered that the bees created comb close to the sugar source at zero gravity and with similar geometry to comb built under gravity except the cells were not consistently angled downwards,

References.

¹ Winston, M. (1987) The Biology of the Honey Bee, Harvard University Press.

²Goodman, L. (2003), Form and Function in the Honey Bee, International Bee Research.

³ VANDENBERG, J.D, MASSIE, D.R, SHIMANUKI, H., PETERSON, J.R. & POSKEVICH, D.M.SURVIVAL, BEHAVIOR AND COMB CONSTRUCTION BY HONEY BEES, APIS MELLIFERA, IN ZERO GRAVITY ABOARD NASA SHUTTLE MISSION STS-13 (1) Apidologie, 1985, 16 (4), 369-384.