Meeting Abstract
The ground plan hypotheses of social evolution argue that the complex divisions of labor observed in eusocial insect societies evolved via the compartmentalization of linked components of an ancestral reproductive cycle into different reproductive and behavioral classes. In some highly social bee species high sensory responsiveness and highly expressed reproductive characters have been linked with pollen collection. Larvae are primarily provisioned with protein rich pollen or pollen-derived material, and the reproductive ground plan hypothesis suggests that these connections are derived from an ancestral linkage between foraging behavior, sensory perception and the reproductive cycle of a solitary female. However, very little is known about such pleiotropic trait associations in less social and solitary bees, which can be used to approximate the solitary ancestors of honey bees and other eusocial lineages. I tested the links between sucrose responsiveness using the proboscis extension reflex (PER) assay, ovarian development and foraging behavior in the facultatively communal orchid bee Euglossa hyacinthina. Orchid bees are particularly interesting for the study of social evolution, as they are the only corbiculate bees that do not display complex social behavior. I found that bees with more developed ovaries were more likely to forage for pollen and were more responsive to sucrose. These findings lend support to the reproductive ground plan hypothesis and demonstrate that further research with orchid bees into the mechanistic regulation of behavior can provide important insights on social evolution.
