Before I go much further into the evolutionary history behind honey bees and beekeeping I need to pause and consider something so obvious it almost escapes notice. In fact, it did escape my notice until just recently when I realized my near-mistake. And I’m talking of course about the nest – or more accurately, the nest and the ability to nest, taking license to use the word as both noun and verb.
It seems to me fundamental that a society of any kind presumes a certain shared space. That presumption may not hold anymore for modern human societies, given our obsession with technology-assisted global connectedness, but even so we still tend to think of societies in terms of assemblies of individuals attached by cultural bonds to a place in geography – American society, British society, the Eastern Apicultural Society, Western Apicultural Society, and so on. The colonial insects seem to think so too – or at least the entomologists who study them, because they invariably fit the description of individuals sharing a place – a nest.
Ever since January in these pages I have been telling a story about the evolution of the honey bee and why it matters for beekeepers. And so this month we envision our ancient honey bee ancestor as a solitary reproductive female – no need to call her a queen – a female with the cognitive capacity for searching for and finding a suitable nest, recognizing landmarks, and navigating about the neighborhood and returning home. Now I am no neurobiologist but I’m sure what I have just described is a herculean feat for a brain of any size, and in fact the vast majority of insects can’t do it (my wife says I can’t either). Most insects are free living in their local habitats with at most only a brief and transitory association with a “place” of any kind, for most of them a sheltered spot to deposit their eggs.
But in the insect order Hymenoptera – the ants, wasps, and bees – nesting is well represented. It may not look like much – a hollow reed or a dead-end tunnel, but among the wasps it is common, and in the bees their descendants it is universal. It is in fact a shared ancient character and if not exclusive to social species (even solitary bees do it) it is nevertheless a necessary precondition to sociality. Nesting allows for parental care of young, defense, food storage, and shelter – all of which are stabilizing forces friendly to the evolution of colonial life. It’s hard to imagine sociality taking off without it. And under the most advanced insect societies nesting has evolved far beyond hollow reeds into elaborate triumphs of animal architecture, like the nest of the honey bee.
It is this nest, of course, that interests us most. But it didn’t just pop up out of nowhere. It is a product of historic precursors of much simpler designs and functions, but unfortunately we do not have a fossil trail back to those precursors. The nests of modern primitively social bees are our best clues, and from them we can infer that nests of our honey bee’s ancient ancestors were simple cavities or tunnels elaborated over time with increasingly complex individualized cells for food storage and developing young. Individualized brood cells seems to be an ancient character, suggesting that protection of the developing young against parasites, weather, or even trampling by nest mates was strongly selected for (Fig. 1). The partitioning of cells is accomplished by a variety of materials including mud, leaf material, or wood paste. Modern species exist in which the cells are separated by exquisitely thin walls of soil glued together by glandular secretions. It is glandular products like these that were the precursors to wax glands in the modern bumble bees (Fig. 2) and honey bees and the subsequent introduction of beeswax into the natural world.
We are on firmer ground when we get …