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This is my first question on this site. If anyone could help me get to the bottom of it, I would be very grateful.

I am currently working on a lecture on kinship in animals. It goes without saying, it includes a part about the good old honeybee and its unusual relatedness coefficients. One of the interesting points I'd like to cover is worker policing, where workers remove eggs of other workers because they are more closely related to their brothers (the queen's sons) than their nephews. The resources I'm using state that this situation depends on whether the queen is monogamous or polygamous. When a queen mates with a single drone, workers are more closely related to their nephews (r=0.375) than their brothers (r=0.25). However, if a queen mates with more drones, the situation is flipped, workers are more closely related to their brothers and therefore eliminate unfertilized eggs laid by other workers.

The issue I'm having may seem silly and purely technical, but I can't for the life of me figure out how we arrive at a relatedness coefficient of 0.375 for worker and nephew when the queen is monogamous. I'd really like to understand this because I want to be able to answer as many potential questions students may have, and I can't do that if I'm not 100% sure about it. Any and all help is greatly appreciated. Thanks in advance!

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  • $\begingroup$ Queens are generally not monogamous. Although they make just one mating flight, they store the sperm of multiple drones. Might your numbers work if you plugged in two, three, or four mates? $\endgroup$ – Karl Kjer Nov 16 '18 at 19:44
  • $\begingroup$ @KarlKjer Thank you for your reply. I'm aware that queens are generally not monogamous, and that the second situation is far more common than the first. My issue was in understanding how we calculate a relatedness od 0.375 for worker and nephew in the event when the queen mates with a single drone. I don't want to include this information in my lecture if I don't fully understand it myself. $\endgroup$ – RedPanda Nov 19 '18 at 7:36
  • $\begingroup$ Is this as simple as: Father of both workers is same, so are their paternal genes b/c he only had one set of chromosomes. The two workers are expected to share half of their maternal DNA. Both parents contributed equally, so the sisters are considered each related to each other at relatedness=0.75. The son of one is related to its mother by 0.5, as it only gets one set of her chromosomes. To determine the relatedness of the aunt to this son, multiply how related she is to her sister times how related he is to his mother: 0.75*0.5-0.375? $\endgroup$ – Michael Jun 16 '19 at 3:38

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