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Social interactions are generally regulated by pheromones that convey information about the identity, physiological state, and location of an individual. The fruit fly, Drosophila melanogaster , offers a powerful model system to study the mechanisms through which pheromones modulate social interactions. Most of the fruit fly’s social behavior is demonstrably modulated by pheromones, and many of the chemical compounds composing its pheromonal profile have been characterized. This chapter describes several behavioral bioassays that can be used to determine the function of contact and short-range volatile pheromones in D. melanogaster’s social behavior. The chapter first provides instructions on how to rear flies for pheromonal experimentation and how to generate flies that cannot produce cuticular hydrocarbons. Afterward, protocols on how to determine the function of pheromones in courtship behavior and mate choice are provided, followed by protocols to determine whether pheromones function as volatile or contact cues during oviposition site selection. Finally, the last section of the chapter gives general advice on how to work with pheromones in the laboratory.

Division of labor and task specialization explain the success of human and insect societies. Social insect colonies are characterized by division of labor, with workers specializing in brood care early and foraging later in life. Theory posits that this task switching requires shifts in responsiveness to task-related cues, yet experimental evidence is weak. Here, we show that a Vitellogenin (Vg) ortholog identified in an RNAseq study on the ant T. longispinosus is involved in this process: using phylogenetic analyses of Vg and Vg-like genes, we firstly show that this candidate gene does not cluster with the intensively studied honey bee Vg but falls into a separate Vg-like A cluster. Secondly, an experimental knockdown of Vg-like A in the fat body caused a reduction in brood care and an increase in nestmate care in young ant workers. Nestmate care is normally exhibited by older workers. We demonstrate experimentally that this task switch is at least partly based on Vg-like A–associated shifts in responsiveness from brood to worker cues. We thus reveal a novel mechanism leading to early behavioral maturation via changes in social cue responsiveness mediated by Vg-like A and associated pathways, which proximately play a role in regulating division of labor.