Hi all
My interest is in figuring out how the diutinus state (long lived) is triggered. One thing that seems significant is the cessation of pollen into the hives. This may shift the bees into a state of dietary restriction.

Dietary restriction (DR), a reduction in nutrient intake without malnutrition, is the most reproducible way to extend adult lifespan in a wide range of organisms, including insects (Mair et al., 2003). DR exerted during adulthood extends lifespan and reduces fertility in Drosophila (Chapman and Partridge, 1996; Nusbaum and Rose, 1999). 

It has been suggested that this effect is adaptive and results from reallocation of resources from reproduction to somatic maintenance, in order to survive periods of DR in nature (Zajitschek et al., 2016). Indeed, lifetime egg production is a good index of fitness and is maximised when females flies are fed a diet with a protein:carbohydrate ration (P:C) of 1:4, this is at the expense of longevity alone, which is maximised by feeding at P:C 1:16. [that is, longevity is maximized when the ratio of carbohydrate to protein is 16 to 1] 

We suggest that investigating the chain of causality from nutritional change to epigenetic change to phenotype is required ... We believe that research should focus on this chain of causality as the only way to clearly demonstrate what is tantalisingly close; a clear understanding of how epigenetics may link environmental effects and final phenotype ...

source: Cridge, A., Harrop, T., Lovegrove, M., Remnant, E., & Dearden, P. (2017). Nutrition and Epigenetic Change in Insects: Evidence and Implications. In Advances in Insect Physiology (Vol. 53, pp. 31-54). Academic Press.

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