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This study examined the nest architecture, colony productivity, and duration of the immature stages of the social wasp Mischocyttarus consimilis Zikáán (Hymenoptera: Vespidae). The study was carried out under field conditions. Nests of M. consimilis consist of a single uncovered comb, which is attached to the substratum by a single petiole. The data for the nest architecture showed a positive and significant correlation between the size of the comb and the diameter of the petiole, and also between the height and diameter of the cells. The nests were constructed on horizontal, vertical, and sloping substrata with no apparent preference for a specific orientation. The colonies produced 72.9 cells and 40.7 adults on average. The mean frequency of productive cells was 33.3%, and 19.4% of the cells were reused. The mean duration of the immature stages combined was 69.7 days and the egg, larval, and pupal stages had mean durations of 14.9, 36.0, and 18.8 days, respectively. The duration of each immature stage was significantly shorter in the warmhumid season, and the larval and pupal stages were shorter during the colony pre-emergence stage.

The division of labor between castes and the division of labor in workers according to age (temporal polyethism) in social wasps are crucial for maintaining social organization. This study evaluated the division of labor between castes, and the temporal polyethism in workers of Mischocyttarus consimilis Zikán (Hymenoptera: Vespidae). To describe the behavioral repertory of this species, observations were made of 21 colonies, with 100 hours of observations. In order to observe temporal polyethism, each newly emerged wasp was marked with colored dots on the upper area of the thorax. This allowed the observation of behavioral acts performed by each worker from the time of emergence to its death. Through hybrid multidimensional scaling, a clear division between queens and workers could be identified, in which the behaviors of physical dominance and food solicitation characterized the queen caste; while behaviors such as adult—adult trophallaxis, destruction of cells, alarm, foraging for prey, foraging for nectar, and unsuccessful foraging characterized the worker caste. Hybrid multidimensional scaling characterized two groups, with intra—nest activities preferentially accomplished by younger workers, while extra—nest activities such as foraging were executed more frequently by older workers.

In the subfamily Polistinae, caste dimorphism is not pronounced and differences among females are primarily physiological and behavioral. We investigated factors that indicate the reproductive status in females of Polistes ferreri Saussure. We analyzed females from nine colonies and evaluated morphometric parameters, ovarian development, occurrence of insemination, relative age, and cuticular chemical profile. The colony females showed three kinds of ovarian development: type A, filamentous ovarioles; type B, ovarioles containing partially developed oocytes; and type C, long and well-developed ovarioles containing two or more mature oocytes. The stepwise discriminant analysis of the cuticular chemical profile showed that it was possible to distinguish the three groups of females: workers 1, workers 2, and queens. However, the stepwise discriminant analysis of the morphological differences did not show significant differences among these groups. The queens were among the older females in the colony and were always inseminated, while the age of the workers varied according to the stage of colony development.

Introduction An important feature for the ecological success of social insects is the division of labor among individuals in their colonies (Wilson, 1985). For this reason, many investigators have devoted their efforts to elucidate the parameters that determine this division, especially the distinction and determination of the caste (Robinson, 1992; O'Donnell, 1995; O'Donnell, 1998). The subfamily Polistinae has characteristics that are important to understand how the social behavior has evolved in the wasps (Ross & Matthews, 1991). The degree of morphological differences among castes in this group can range from total absence (Richards, 1971; Strassmann et al., 2002) to sharp differences among castes (Jeanne, 1991). This, indeed, may be a key feature in the evolution of social insects, since the presence of wide differentiation among castes indicates a higher degree of sociality (Bourke, 1999). In the basal Polistinae such as Mischocyttarus and Polistes, females are distinguished by their behavior, dominance hierarchy, degree of ovarian development and/or their Abstract A fundamental feature in the evolution of social insects is the separation of castes, and the presence of wide differentiation between castes indicates a more advanced degree of sociability. In this study, we evaluated factors indicating the reproductive status of females in colonies of the social wasp Polistes versicolor. The reproductive status of each female was examined by measuring nine morphometric characters, by tracing the cuticular chemical profile, by evidence of insemination and by recording the relative age. We conclude that P. versicolor colonies present 3 female groups according to cuticular chemical profile difference. The first group is made of females with filamentous ovarioles, typical of workers; the second one is females with intermediate ovarioles; and the third group is the group of the queens, which are older females, already inseminated and with the greatest degree of ovarian development. No significant external morphological differences were found among these female groups. Therefore, despite the lack of significant morphological differences among females, there are other factors such as the chemical composition of the cuticula, which are indicative of the reproductive physiological condition of the female in the colony.