The contradictions in the sexuality of bees...

[Herbsandveg]

I am very interested in bumblebees, but am surprised and confused by the apparent contradiction around the factors which determine the gender of their offspring.

My understanding is that if a Queen bumblebee lays an unfertilised egg, it will produce a male, but if she fertilises the egg by introducing the sperm she retained from mating, then the resultant offspring would be female. I would have thought the reverse would be the case, and that it would be the introduction of the male sperm that would produce a male, and not the other way round.

Could anyone explain for me, please, how this would be the case?

[ameno]

Your confusion arises from your assumption that sex determination in bees is the same as it is in humans.
Only mammals use the X/Y system. Even other vertebrates don't, much less invertebrates.
In the case of bees, males are haploid - they have only a single set of chromosomes. Females, on the other hand, are diploid, possessing a proper double set of chromosomes.
Thus, males can be produced from unfertilised eggs produced by the queen, whereas females require fertilisation.

[Herbsandveg]

Many thanks for explaining this. Ameno. I had no idea that this was the case, and I’m grateful for your help. Thank you again.

[Nicos]

Interesting ameno -thanks!

[fishpond]

Amazingly interesting.
This raises many questions, for instance:- Is one single Bbee in charge of saying how many small/large cells there are in a nest, therefore dictating how many male/female Bbees there are in a nest?
Chistmas Wishes to you all .
Bob

[nickdub]

I'm not so up on bumblebees, as I am on honeybees, but as far as this question goes, I think the general situation is much the same. A virgin honeybee queen is fertilised on her mating flight by drones (the males). Once she returns to the colony the new queen can lay either female eggs (workers) which are fertilised using the drone's semen she keeps inside her, or unfertilised male eggs (new drones).
Worker bees, being females, can lay eggs too, but they usually do not do this if there is a viable queen in the colony. As these worker bees are all virgins and can never mate, they only ever lay male eggs. New queens are produced from fertilised eggs laid by the old queen and fed on royal jelly, so they develop more and are slightly bigger than a standard worker. They are raised in bigger cells called queen cells. In an emergency newly-laid worker bee eggs can be converted in to Queens by the workers treating them differently. Beekeepers can use this by moving a comb of newly laid eggs from a hive with a functioning queen into a colony which has lost its queen. In honeybees the cell size needed by drones is a little larger than that needed by a worker. If you buy or make wax foundation for storing honey then drone sized imprints are usually used because this means the honey to wax ratio is higher. But if you want to make up frames to expand a new colony then worker sized foundation is needed.
Bees act largely by instinct a bit like mini automata. For example, drones no longer being needed at the end of summer are excluded from the colony by the workers and as they cannot get nectar for themselves they die off in a day or so. New queens will also kill off any rival queens they can get to by using their sting and so it is very unusual to find more than one queen in a hive, unless the colony is about to swarm.
It is obvious that, as honey bees are social animals and cannot survive or breed outside a large colony, the only way for them to increase their numbers and spread is to divide an existing colony into two or more parts. We call this swarming. The first swarm of the season in the UK usually happens in May and in this swarm the old Queen leaves the hive for the first time in her life since her mating flight. She will be accompanied by thousands of workers who all fill up on honey before they set off. Scent is very important to how bees communicate and so the scent of the queen allows her workers to find her. Usually the swarm will head of to a dark dry place with a small entrance which is reasonably warm. They prefer somewhere in which bees have lived before like an old hive or a hole in a tree where the previous colony died out for some reason.

[Plot70]

It is not unknown for honey bee swarm to find a safe place guarded with an electric fence literally.
https://golbornevintageradio.co.uk/f....php?aid=20206