A Few Good Men…(or drones)

Anyone who has already done a bit of bee reading knows that there three bee castes in a hive. The Queen, the worker bees, and the drones. Most will also know that queens and workers are from fertilised eggs and drones are from un-fertilised eggs (this process is called parthenogenesis). Drones are the pure off-spring of the queen which makes them more like the workers’ uncles than their brothers. As such drones only have half the number of genes than their female relatives having only the genes provided by the egg. Females have 32 chromosomes, drones have 16 chromosomes. All 10 million (give-or-take) sperm that the drone produces are identical clones with no variation. On mating a Queen will perhaps mate with upto 20 drones. So although all the workers have the same mother they may have different fathers. Those who have the same mother and father are related by 75% of their genes and are termed supersisters. Workers are therefore more genetically related to a supersister raised as a queen (75%) than they would be to their own direct offspring (50%). This explains in an evolutionary sense why workers would fight to the death to save the offspring of a different individual OR more correctly why this behaviour has been maintained.

Where am I going with this?
good question!

Drones are mostly overlooked in beekeeping. They are considered lazy do nothings and conventionally foundation is used to constrict the bees to making workers. Of course there is one thing they do very well, and that is chase down virgin queens. Their whole physiology is attuned to it. Big top mounted eyes to spot the queen and approach from underneath. Large size to fly fast and of course a penis nearly as long as he is. The very fact that even constrained a colony strives to make drones suggests that either they perform some other important functions we are unaware of or this one function is SO important the bees will invest time, and resources to support it. We like to think with queens the bigger the better. Some beekeepers even tear down small queen cells. I think this is even more the case for drones and we force them to make drones in small cells at low numbers and then wonder why our queens are poorly mated.

There is also a lot of attention on queens for developing colony traits like behaviour, productivity, disease resistance, frugality, and overwintering success. Queens though are only one half of this genetic equation and the slower more complicated half at that. I will explain this in more detail below but the take home message is IF YOU HAVE A GOOD QUEEN LET HER MAKE DRONES NOT JUST MORE QUEENS thanks.

There four driving principles of natural selection:
Variability – Diversity of genotype (genetics material) and phenotype (its appearance/characteristic).
Inheritance – The passing on of distinctive genetics or characteristics to subsequent generations.
Selective Pressures – Other factors that cause a characteristic to become a positive OR negative influence on an individual’s chances of survival.
Survival of the Fittest – Better termed as opportunity to reproduce through not dying!

Absolutely raise queens from good queens. Traits around productivity and behaviour are good bred in or out in this way. Queens though, live a long time, take a while to show their colours, and because they mate with so many drones the genetics gets complicated to track. Because each colony can only produce one of two drone “types” and these are all culled at the end of the season drones are a much faster way for a colony to select for successful genetics. Any pressures being put on a colony in terms of disease, climate, or location can rapidly effect drone success.
If allowed to make drones here is how they can help all beekeepers in an area.

a) only successful colonies makes drones.
b) The bigger and more successful the colony the greater the number of drones produced.
c) within a colony the more successful it’s supersisters are the more of that drone type is produced.
d) those drones adversely affected by disease or the environment do not get to mate.
e) if d) then the colony will produce more of its other drone type to compensate (the one not badly affected).
f) if both drones types (that is all the queen’s genetics) are affected badly the colony will produce only a few weaker drones. Provided other colonies are allowed to produce drones the successful ones will be bigger, stronger, and more numerous so will be the ones to mate with the queens conserving the successful genetics.

The genetics of “hygienic” behaviour is becoming better understood every day. That is to say, it is getting more complicated and harder to explain. So instead I will go with a very simple model of varroa sensitive. Let us say there is a varroa sensitive trait which resides in one of the chromosome sets a queen can pass on (this is shown in red; and yes that is supposed to be a varroa not a tomato). This queen may mate with any number of drones but will always pass on this sensitivity to half of its female offspring.

varroa sens

This is where the supersisters kick in. We know that these supersisters congregate on combs and display nepotism. They will feed and care for the workers, queens, and drones they are more closely related to. Many of the viruses associated with parasitic mites are transferred by the nurse bees. Without allowing all of colonies to raise drones the strongest/healthiest/best adapted cannot prevail. Culling or restricting drones levels the playing field reducing the margin the wouldbe successful drones with have otherwise. I really struggled in my first few years with queens failing to mate. I now have four different queen lines in my apiary all producing drones and the queens are laying like billy-o. Oh ..and the importing of genetically “pure” queens! don’t get me started 😦

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7 Responses to A Few Good Men…(or drones)

  1. Julie says:

    Loved this post. Ever since I started beekeeping, I’ve felt like the production of drones is a really important thing for colonies, but I haven’t had any objective reasons for that other than Nature wouldn’t spend the resources on them if they weren’t necessary. However, this post provided some excellent reasons other an gut-feeling for keeping them around. Thanks for this one!

  2. Steve Webb says:

    Thank you for the blog. Fascinating. The more I learn about bees the more it seems traditional beekeeping intervention can harm the species chances of survival.

    • deweysanchez says:

      They are addictive little beasts.
      We do seem to have learned lessons in every other field which haven’t even dented the shell of beekeeping dogma. …Don’t narrow genetic pools as this breeds in weaknesses, don’t treatment for some diseases prophylactically as they develop resistance. etc etc. They have managed nearly 70 million years without us and we’re convinced if we don’t inspect every week something bad will happen.

  3. Erik says:

    Great summary, thanks for putting this together. Thomas Seeley did a study of wild bees impacted by Varroa. He had samples from the 1970’s and the present to compare genetic lines. Even though a number queen genetics had died out, the colonies produced drones and the male lines were present in future lines. A dying colony can still produce males and keep some of their genetics alive. A very interesting topic. http://news.cornell.edu/stories/2015/08/some-honeybee-colonies-adapt-wake-deadly-mites

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