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Informed Discussion of Beekeeping Issues and Bee Biology

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Subject:
From:
Peter L Borst <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Wed, 22 Jan 2014 08:08:11 -0500
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Beekeepers have long pondered what initiates brood rearing in mid winter. What follows is an ongoing discussion from another group:

Statement:
> It is well known and commonly discussed by beekeepers in the south that the Solstice is the turning point when hives turn around start to grow in the winter.

My response:

It is logical to assume that the increase in day length correlates to the increase in brood rearing in the honey bee hive. However, as we have pointed out, this increase occurs in total absence of light. In the north hives are often packed, or buried in the snow, or placed in dark buildings. Yet the brood rearing begins anyway. 

The cessation of brood rearing in the fall is generally thought to be initiated by the end of food input. Reproduction in many animals is curtailed by food shortage. It appears that there is a waiting period and then some sort of internal clock triggers the resumption of breeding in animals that winter in the dark, or in the tropics where there is no change in day length

Reference:

> In summer breeders (e.g., several hamster, vole, and mouse species), decreasing summer day lengths induce reproductive involution. The non-reproductive phenotype is sustained for several months thereafter by the inhibitory short days of late summer, autumn, and early winter. Mid-winter reactivation of the reproductive system is triggered after 20–25 weeks of exposure to decreasing or short days by an interval timer that renders the reproductive neuroendocrine system refractory to short days.

Prendergast, B. J. (2005). Internalization of seasonal time. Hormones and behavior, 48(5), 503-511.

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