kingroup is an open source java program implementing a maximum likelihood approach to pedigree relationships reconstruction and kin group assignment. kingroup implements a new method (currently being performance tested) for reconstructing groups of kin that share a common relationship by estimating an overall likelihood for alternative partitions. A number of features found in kinship (Goodnight & Queller 1999) have also been implemented to make them available outside the Classic Macintosh OS platform for the first time.

High-resolution genetic markers have revolutionized our understanding of vertebrate mating systems, but have so far yielded few comparable surprises about kinship in social insects. Here we use microsatellite markers to reveal an unexpected and unique social system in what is probably the best-studied social wasp, Polistes dominulus. Social insect colonies are nearly always composed of close relatives; therefore, non-reproductive helping behaviour can be favoured by kin selection, because the helpers aid reproductives who share their genes. In P. dominulus, however, 35% of foundress nestmates are unrelated and gain no such advantage. The P. dominulus system is unlike all other cases of unrelated social insects, because one individual has nearly complete reproductive dominance over subordinates who could have chosen other reproductive options. The only significant advantage that subordinates obtain is a chance at later reproduction, particularly if the queen dies. Thus, P. dominulus societies are functionally unlike other social insects, but similar to certain vertebrate societies, in which the unrelated helpers gain through inheritance of a territory or a mate.

Comparative sociogenomics has the potential to provide important insights into how social behaviour evolved. We examined brain gene expression profiles of the primitively eusocial wasp Polistes metricus and compared the results with a growing base of brain gene expression information for the advanced eusocial honeybee, Apis mellifera. We studied four female wasp groups that show variation in foraging/provisioning behaviour and reproductive status, using our newly developed microarray representing approximately 3248 P. metricus genes based on sequences generated from high-throughput pyrosequencing. We found differences in the expression of approximately 389 genes across the four groups. Pathways known from Drosophila melanogaster to be related to lipid metabolism, heat and stress response, and various forms of solitary behaviour were associated with behavioural differences among wasps. Fortyfive per cent of differentially expressed transcripts showed significant associations with foraging/provisioning status, and 14 per cent with reproductive status. By comparing these two gene lists with lists of genes previously shown to be differentially expressed in association with honeybee division of labour, we found a significant overlap of genes associated with foraging/provisioning, but not reproduction, across the two species. These results suggest common molecular roots for foraging division of labour in two independently evolved social insect species and the possibility of more lineage-specific roots of reproductive behaviour. We explore the implications of these findings for the idea that there is a conserved 'genetic toolkit' for division of labour across multiple lineages.

Colonies of social wasps, ants, and bees are characterized by the production of two phenotypes of female offspring, workers that remain at their natal nest and nonworkers that are potential colony reproductives of the next generation. The phenotype difference includes morphology and is fixed during larval development in ants, honey bees, and some social wasps, all of which represent an advanced state of sociality. Paper wasps (Polistes) lack morphological castes and are thought to more closely resemble an ancestral state of sociality wherein the phenotype difference between workers and nonworkers is established only during adult life. We address an alternative hypothesis: a bias toward the potential reproductive (gyne) phenotype among Polistes female offspring occurs during larval development and is based on a facultatively expressed ancestral life history trait: diapause. We show that two signatures of diapause (extended maturation time and enhanced synthesis and sequestration of a hexameric storage protein) characterize the development of gyne offspring in Polistes metricus. Hexameric storage proteins are implicated in silencing juvenile hormone signaling, which is a prerequisite for diapause. Diverging hexamerin protein dynamics driven by changes in larval provisioning levels thereby provide one possible mechanism that can cause an adaptive shift in phenotype bias during the Polistes colony cycle. This ontogenetic basis for alternative female phenotypes in Polistes challenges the view that workers and gynes represent behavior options equally available to every female offspring, and it exemplifies how social insect castes can evolve from casteless lineages.caste development ͉ hexameric storage proteins ͉ juvenile hormone ͉ life-history pleiotropy ͉ social behavior S ocial insects often show pronounced differences in behavior, physiology, and morphology between castes of workers (functionally sterile helpers) and reproductives (1).

In order to gain insights into the mechanistic basis of caste and behavioral differences in Polistes paper wasps, we examined abdominal lipid stores and ovary development in Polistes metricus females in four groups: foundresses, queens, workers, and gynes. Queens had the largest ovaries, followed by foundresses, workers, and gynes. Gynes had 6x higher lipid stores than the other groups, and lipid stores were lower in foragers (foundresses, workers) than non-foragers (queens, gynes). Lipid levels and ovary development were negatively correlated across the four groups, but removing gynes from the analysis revealed a significant positive correlation for foundresses, workers, and queens, suggesting different energy allocation strategies for gynes vs. other groups. Expression levels of 9 genes (including three in the insulin pathway), examined in a previous study, correlated with either lipid stores or ovary development. These correlative results suggest important relationships between nutrition, reproduction, and division of labor in primitively social insects. We also show that it is possible to assign P. metricus females to one of the four female groups on the basis of wing wear (an indicator of foraging experience), lipid stores, and ovary development, which can facilitate caste-specific collections for future studies.