FIGURING OUT why some bees are social, some solitary and some communal (but solitary) is one honey of a research problem. But Lawrence Packer isn't daunted. Packer researches bees. Not honeybees ("Everybody does that," he says), but some of the 30,000 other bee species, most of which are studied by only a handful of scientists. Specifically, Packer's research focuses on a group of related bee species called sweatbees. They're a good subject for study because while species are closely related they can have very different ways of living. Some are solitary. While others form colonies much like honeybees and bumblebees. Although we think of huge hives as the norm for bees, they're actually relatively rare, Packer says. "Most bees are solitary and nest on the ground or holes in wood." Another common misconception is that beehives are orderly societies. They're not. Packer is looking for answers to the question of how you get from ancestral insects (who lived solitary lives) to today's social, hive dwelling insects. Sweatbees may provide some clues. One theory to explain the evolution of social behaviour is called kin selection. The idea is that each individual tries to maximize the number of its genes in the next generation. Among bees, females get a bigger bang for their evolutionary buck by raising sisters rather than daughters. This leads to two predictions about the early stages of social behaviour's evolution which is, that the females should "bias" the sex ratio to produce more females and that they should produce males themselves. Both predictions were proved accurate by Packer's study. Beehaviour Illustration: Matt Mays