Sunday, September 26, 2010

Something of a stretch: How a Pregnant Polar Bear and a Queen Bee are similar

In some mysterious way not fully understood by either mammalogists or entomologists, in both cases the female in question has some control over her internal reproductive system.
Female polar bears will come into estrus in the spring, and mate with a male of the species. But then she will – somehow – delay implantation of the fertilized ova until she has gained enough weight to successfully carry her cubs to term. It is not known how she manages this. Does a certain avoirdupois trigger the implantation? Do hormones do the trick?

The Queen Bee, who busily lays up to 2000 eggs a day during the honey season, must deposit either fertilized or unfertilized egg in the honeycomb cell presented to her by the workers of the hive. They are the ones who make the cells of the correct size, smaller for the worker females, larger for the male drones. The workers decide whether the hive needs more workers, or a few more drones to go out and disseminate their genetic matter. The Queen uses her front legs to gauge the cell’s diameter, and then backs into the cell and as the egg passes through her oviduct, she either fertilizes it or not.

When the Queen was mated on that fateful nuptial flight, she stored all the sperm in her ‘spermatheca’. This is a small sac next to and connected to her vagina via a small duct, through which she will discharge the spermatozoa when she determines to lay a fertilized egg.
We don’t quite know how she does it. What chaos would transpire if we mere humans had that ability?

You can imagine how delighted I was when I learned from our marine mammalogist on board the Lyubov Orlova of this quirk in the reproductive cycle of the polar bear, and quickly saw its tenuous similarity to the case of the Queen Bee. I tried to share my enthusiasm with several other Arctic travelers, but just then there were several thick-billed murres flitting across the sky – and they beckoned more than a Queen Bee’s reproductive talents.

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