CHESHIRE BEEKEEPERS' ASSOCIATION

Apes curamus et nos curant (We look after bees and they look after us)
Founded 1899
Registered Charity No. 227494
We've been buzzing over 100 years 1899-2016

Do drones need more energy than workers ?

I am sure I once read that flying bees need a certain amount of carbohydrates derived from honey in order to fly and they also need pollen for protein. But Drones need more of both. Can you shed a bit of light on this?

Ross Campbell, Angus

Indeed drones do seem to need more fuel, they are larger of course, but then heavily-laden workers also have quite a weight to carry (a 90mg worker can carry a load of 40mg in flight).

Workers would also appear to have a superior ability to convert substances other than sugars, (e.g. starches) into useable energy. In energy experiments where workers were fed glucose and added starch it was found that they increased their flying time. The same trial with drones showed a reduction in flying time and distance for the starch-enhanced feed. It may be that drones are optimised to use readily available blood sugars; they are sprinters rather than long-distance runners � designed for the chase.

Pollens, whilst being the source of protein for bees, are also a source of energy and most pollen whilst having up to 35 percent protein can also have up to 15 percent fat and up to 40 percent sugars.

Workers produce the sugar-inverting enzyme invertase in their hypopharyngeal head-glands and of course brood-food and royal jelly (the two are basically the same but slightly different depending on whether it is being fed to worker grubs or queens); drones have no such ability. The worker is thus better equipped to make use of intake-nutrients than the drone. Complex sugars such as sucrose when inverted into the simple sugars such as glucose and fructose are readily usable by the bee at 50% water dilution. These sugars are broken down and stored as glycogen which can be used by the muscle cells (via the Kreb�s cycle) to produce energy. Kreb�s cycle is the process employed by the mitochondria within all our cells (all of us animals that is), to carry out this conversion. The mitochondria are remnants of a long-distant bacterium which took up residence in our cells to carry out the trick of burning glycogen in oxygen to produce energy �a good thing too, since oxygen would be toxic to our cells without them. It is forever a wonder that this complex cell �habitation� manages to pass over successfully during cell division, especially the complex divisions during the reproductive cycle.

Theoretically, the energy in one ounce of honey would provide a worker bee with enough energy to fly around the world (at 15mph). Flying is however a �fast living� activity, workers having an average flying lifespan in summer of only 20 to 40 days. (in the quiescence of winter they live up to 140 days).

The three castes exhibit quite different natural life expectancies and it is likely that the cell DNA programs are altered early in life as a result of the differences in brood-feeding.

With thanks to the �Beemaster� of The Scottish Beekeeper magazine, via eBEES

© 2015 Cheshire Beekeepers' Association