Work in my lab aims to understand both the evolution of behavior, and the role of behavior in shaping evolutionary change. Specifically we focus on i) social behavior in sweat bees (Halictidae) to understand the origins of sociality; ii) fungus-growing ants (Attini) to understand the evolution of social complexity, especially with respect to symbiosis, disease and public health; iii) phenotypic innovations that enable night-vision in nocturnal bees, which we use to understand how niche shifts facilitate adaptive radiations; and iv) brain allometry in miniaturized arthropods.
For more than 10 years I have been developing nocturnal sweat bees, Megalopta, as non-traditional model organisms for the study of the evolution of social behavior. Halictidae is one of the few taxon of bees in which both solitary and social behavior occurs in closely related species (or within one species). Thus, they provide numerous opportunities for comparisons with well-known social insects (e.g., honeybees, ants). Megalopta is the most speciose taxon of nocturnal bees, comprised of about 30 species, including brood parasitic ("cuckoo") species. They are facultatively social, so traits of interest can be evaluated in solitary bees, social dominants, and social subordinates. Extensive biological information is already available to provide a comparative framework for genomic projects, including the bases for dominance behaviors and social competition; reproductive physiology including relationships between ovarian size, juvenile hormone titers, vitellogenin titers; the relationships between social role and body size, brain size, or resource availability; parasite pressure and the expression of social behavior; social benefits that accrue from symbiotic associations with nematodes, mites, and bacteria within brood cells. A phylogeny is available, as are other tools, such as microsatellite markers and an EST library used to construct a DNA microarray. Recent collaborators include Adam Smith, Karen Kapheim, Simon Tierney, Natalia Biani, Ulrich Mueller, Quinn McFrederick, Kate Ihle, Rob Page, Gro Amdam, Collin Brent, Andres Quinones, among others.
Invasion of a new niche requires a change in behavior that invariably establishes new selection pressures. To understand the causes and consequences of such shifts we study the visual ecology of nocturnal bees because relevant environmental features are easily measured (photon number). To date most studies have focussed on visually-guided behavior, neurophysiology and neuroanatomy. Collaborators include Eric Warrant, Rick Berry, Emily Baird.
About five years ago I set up a modern neurobiology laboratory to pioneer studies using evolutionary patterns in arthropods to understand rules of brain scaling in minute taxa, and to understand how miniaturized taxa accommodate relatively large brains. We are also interested in the behavioral consequences of brain miniaturization, which currently involves work on learning in bees. Current collaborators include Andre Riveros, Gloria Vargas and Bill Eberhard.
STRI is the world's center for field-based research on the biology of fungus-growing ants. Done in collaboration with fellows, Smithsonian staff, and visiting scientists, there are numerous opportunities to ask questions about the evolution of social complexity, the evolution of mutualistic consortia (ant + fungi vs. plant + endophytic fungi), and the evolution of public health systems in non-human societies. In collaboration with anthropologists at Arizona State University, we are beginning comparative work to explicitly address parallels between public health systems of insect societies and indigenous human societies. As part of a collaborative effort with colleagues at the National Museum of Natural History, the University of Copenhagen, and the Beijing Genomics Institute, genomes will be available for all representatives of the higher attines. Collaborators include Sunshine Van Bael, Catalina Estrada, Hermogenes Fernandez, Hubert Herz, Ted Schultz, Sean Brady, Koos Boomsma, Ulrich Mueller, Kim Hill, Magdalena Hurtado, and Juergen Liebig, among others.