South American species in the seed-harvester ant genus Pogonomyrmex (subfamily Myrmicinae) are interesting biologically because of their numerous queen phenotypes and life histories. This paper provides a taxonomic revision and reviews the natural history for 21 South American species of Pogonomyrmex so that we can better study their rich and interesting ecology, life history, and evolution. Sp...

In social insects, resource allocation is a key factor that influences colony survival and growth. Optimal allocation to queens and brood is essential for maximum colony productivity, requiring colony members to have information on the total reproductive power in colonies. However, the mechanisms regulating egg production relative to the current labour force for brood care remain poorly known. ...

Worker sterility in honeybees is neither absolute nor irreversible. Whether under queen or worker control, it is likely to be mediated by pheromones. Queen-specific pheromones are not exclusive to queens; workers with activated ovaries also produce them. The association between ovarian activation and queen-like pheromone occurrence suggests the latter as providing a reliable signal of reproduct...

We examined changes in the content of biogenic amines in the brains of ant queen associated with early colony establishment. In ants, including Formica japonica, winged virgin queens lose their wings following copulation, and then start establishing a colony. Significant changes in brain biogenic amine content in the queen are associated with transition from winged virgin queen to wingless mate...

Three experiments investigated young children’s ability to use a causal property, making a machine light up and play music, to sort objects together (sorting task), and then to predict how to make the machine work (action task). The results show that the performance of 30-month-old children is guided in both tasks by the causal properties of the objects. This suggests that causal information is...

Theoretical and empirical studies have suggested that an underestimate of the ENSO asymmetry may be accompanied by a climatologically smaller and warmer western Pacific warm pool. In light of this suggestion, simulations of the tropical Pacific climate by 19 Coupled Model Intercomparison Project Phase 3 (CMIP3) climate models that do not use flux adjustment were evaluated. Our evaluation reveal...

A trademark of eusocial insect species is reproductive division of labor, in which workers forego their own reproduction while the queen produces almost all offspring. The presence of the queen is key for maintaining social harmony, but the specific role of the queen in the evolution of eusociality remains unclear. A long-discussed scenario is that a queen either behaviorally or chemically ster...

Queens in primitively eusocial insect societies are morphologically indistinguishable from their workers, and occupy the highest position in the dominance hierarchy. Such queens are believed to use aggression to maintain worker activity and reproductive monopoly in the colony. However, in the primitively eusocial wasp Ropalidia marginata, the queen is a strikingly docile individual, who interac...