Bringing population ecology back to wild bees

In recent years, motivated by widespread declines in wild bees, ecologists have prioritized learning about patterns of wild bee communities across the landscape at the expense of learning about the population-level mechanisms driving those patterns. In this essay, we seek to revitalize the tradition of studying wild bee populations in a way that both contributes key knowledge for bee conservation and builds a strong conceptual understanding of the processes underpinning bee populations. We address two widespread concerns about investing in population-level research. First, that population-level studies are too conceptually narrow to provide broad inference. If population-level studies are couched in general ecological theory, then findings from a single species can be generalized to many. We highlight how wild bees would make excellent candidates for exploring five areas of general ideas in population ecology, including nutritional ecology, drivers of vital rates, phenology and voltinism, habitat selection, and movement. Second, we address the concern that methods for studying bees at the population level are too difficult to implement. Methods for conducting population-level studies of bees—specifically, identifying living bees in the field and studying individuals throughout their life cycles—are feasible to implement at the scales appropriate for answering population-level questions, for example, a few species at a few sites. To facilitate adoption of these ideas, we developed an online field guide (www.watchingbees.com) and a detailed methods manual. More generally, we emphasize the value of linking data-rich pattern-oriented approaches in ecology with an understanding of the basic biology and mechanisms that generate those patterns.