Bee use of propolis
Do we know how long bees have been producing propolis? In the bee and wasp family, only honey bees exhibit this trait — is that correct?
Calum Grigor
Germany, December
A
Sawflies, wasps, bees, and ants belong to the insect order Hymenoptera (from the Greek: hymen — membrane, optera — wing, or membranous wings). Honey bees are not the only hymenopterans to use plant resins. We (folks who work with honey bees in any capacity) use the word “propolis” to describe the mixture of plant resins, other plant compounds, and wax that honey bees mix for use in their hives. Propolis is primarily a mixture of plant resins. We may not call the material that other bees and wasps use “propolis,” but it still represents resin use similar to how honey bees use it. These reasons include building/fortifying nests, disease/pest control, and storage of foodstuffs. From Simone-Finstrom and Spivak (2010 — citation below), a great review of propolis use by honey bees:
It is not known if resin collection evolved several times among the ants and bees. The evolution of these behavioral disease resistance mechanisms is also currently unknown.
It appears, then, that this behavior has existed for a long time, and probably predates honey bees, given that other bees, wasps, and ants use plant resins.
Simone-Finstrom and Spivak. 2010. Propolis and bee health: the natural history and significance of resin use by honey bees. Apidologie, 41: 295-311. https://doi.org/10.1051/apido/2010016
Winter Bees
My question concerns the development of “fat” winter bees. I understand the lives of summer bees are far shorter than their winter sisters. And I have read that winter bees have higher amounts of fat bodies. But how does that happen? Do the larvae of winter bees get a different diet — perhaps an extra day or two of royal jelly (versus three days for summer bees), a day or two more in development, perhaps? Or do winter bees, as adults, live longer because they are not out doing the dangerous and vigorous work of foraging? Perhaps adult winter bees eat more bee bread (pollen)? Maybe a combination of factors?
Jean Miller
December
A
You are in luck! I could not have answered this question two months ago. However, I can answer it now. Why? As you know, my team and I produce a podcast entitled “Two Bees in a Podcast? (https://entnemdept.ufl.edu/honey-bee/podcast/). I am fortunate to co-host this podcast with Ms. Amy Vu, State Specialized Extension Agent here at the University of Florida. We recently interviewed Dr. Gabriela Quinlan, a Research Ecologist with the USDA-ARS, on this very topic. The interview was great, and I really learned a lot about winter bees in the process. I will summarize our discussion here, but I strongly encourage you (and other readers of this column) to listen to Episode 193 of “Two Bees in a Podcast” for more information.
For the benefit of all readers, I will start by explaining what is meant by “winter bees.” You all likely have heard that worker honey bees live up to about six weeks in spring and summer and up to six months in late fall and winter. We all know, then, that the bees that carry the colony through winter have longer lifespans than those that compose the colony in spring and summer. This has led scientists to look at the key differences between these long-lived bees and their short-lived sisters. This led to the discovery of differences in physiology, behavior, morphology, and other parameters between the two bee types.
Shortly thereafter, beekeepers and bee scientists called these longer-living bees that carry the colony through winter “winter bees” and the shorter-living bees present in the hive the rest of the year “summer bees.” This idea has become so commonplace in our industry that I regularly hear about winter bees at nearly every beekeeper meeting I attend. Scientists, too, have taken a considerable interest in this topic, with Dr. Quinlan being among the foremost experts on winter bee development.
The main conclusion from our interview first: Scientists are not in agreement regarding the answer to the development of winter bees. There are competing, and complementary, hypotheses. For example, Dr. Quinlan mentioned the “nurse’s load” hypothesis. Being a nurse honey bee is energetically taxing. Workers deplete their own fat bodies to make the brood food that they feed to developing larvae. Nurse bees present in the nest in late fall have no brood to feed. Thus, they get to hold onto their fat reserves, rather than deplete them to produce brood food.
Similar to this is a second hypothesis that concerns just general level of activity. It is possible that winter bees live longer than do summer bees simply because they have less work to do. They do not need to build comb, feed brood, or forage. Maybe the lessened work load leads to …
