Eusociality, a major evolutionary innovation defined by a partitioning of reproduction between genetically related ‘queen’ egg-layers and generally sterile ‘worker’ castes, has arisen numerous times in insects and enables increased ecological dominance. Transitions to eusociality are accompanied by complex signaling systems, frequently involving specific chemicals that mediate coordination of activity at the superorganismal scale. Queen pheromones (QPs) that induce short term behavioral ‘releaser’ and longer term physiological ‘primer’ effects on workers are of critical importance among these various signal axes, because they dictate the defining feature of eusociality: a reproductive differentiation of castes. An overarching aim of this dissertation is to illuminate the early origin of the QP signaling channel, which is ubiquitous among highly eusocial insects but poorly understood in its early stages. Is the early origin of QPs defined by a chemical manipulation of nascent workers against their best interests? Or, alternatively, are primordial QPs honest chemical advertisements of queen reproductive potential, allowing workers to optimally invest in their queens’ reproductive futures? To distinguish between these alternatives, I focus on the tropical sweat bee Megalopta genalis (Hymenoptera: Halictidae), a species representative of the earliest stages of eusocial evolution in which simple eusociality is polyphenic at the population level and workers retain the option of reproducing independently. In chapter 1, I analyze glandular and cuticular chemistry across reproductive (solitaries and queens) and non-reproductive (worker) phenotypes, identifying candidate QPs associated with reproduction and queenship. In chapter 2, I use synthetic mixtures of candidate compounds – linear alkanes, methylalkanes, and macrocyclic lactones in their natural amounts and ratios – to show that a bouquet of methylalkanes (MAs) serves as the QP of M. genalis. I then show that MAs are true signals modulated by social context, which are predictive of queen ovarian development, egg-laying rates, and worker inclusive fitness returns under natural conditions. I also provide evidence that the shared requirement of essential amino acids for queen fecundity (oogenesis) and QP signal (MA) biosynthesis may underpin this predictive relationship. Finally, I find that reproductively labile workers preferentially labor for queens that produce higher amounts of MA, consistent with an ‘honest signal’ role for QPs in enabling optimal allocation of worker reproductive investment. In chapter 3, I close by surveying brood chemistry and demonstrate that MAs occur at a high concentration on the surface of queen-laid eggs. Unlike other eusocial lineages in which QP deposition on eggs occurs, M. genalis is a mass provisioner and workers do not regularly contact the eggs or low-volatility MAs thereon. I argue that MAs on the egg surface have a non-communicative function that may have preceded their evolution as QPs, aligning with a ‘sender-precursor’ model of QP evolution. Taken together, the results of these three chapters are significant in that they demonstrate the use of ‘honest’ QPs prior to the fixation of obligate eusociality, and further indicate that these chemical signals may catalyze the formation of simple eusocial societies. This leads to a view that QPs do not simply arise to meet the communicative needs of advanced eusocial societies, but rather play a more active role in facilitating their evolution by reliably communicating the kin-selected benefits of cooperation.