Bee nests

Female bees construct nests to receive food that will be transformed into larvae, pupae, and then adult bees. To allow this process, the basic components of most bee nests are similar. They have an entrance, a main burrow or nest cavity, and cells or a brood chamber in which immature bees are reared in closed or protected compartments. At one extreme, the small, simple nests of solitary bees are shallow excavations. An unornamented hole terminates in a single cell having an inner surface barely different from the substrate. The first bees probably burrowed in the soil and nested in this way. Such nests, each composed of a single cell at the burrow's end, are now found among some primitive wasps. Through their elaboration, the nest architecture widespread among the sphecoid wasps and presumably the ancestors of bees has developed (Malyshev 1935; Michener 1964b; Brothers 1975; Bohart and Menke 1976; Iwata 1976). Evidently, intense pressure from natural enemies can force tropical bees to construct nests that consist of only one brood cell (Vinson, Frankie, and Coville 1987). However, solitary female bees usually build and provision at least five or six cells in each nest and then may go on to construct additional nests (Malyshev 1935).

Different sections of the burrow serve different purposes. The main burrow penetrates the substrate, separates the larvae from potential enemies, allows bees to develop in suitable conditions, and provides an exit when they emerge as adults.