Intra-caste size differences between two social forms of the southern yellowjacket, Vespula squamosa (Hymenoptera, Vespidae)

Changes in intraspecific social organization are of particular interest to sociobiologists, because an understanding of the genetic and ecological determinants of different social forms bears on the origins of sociality and mating isolation. The Southern Yellowjacket, Vespula squamosa (Drury), occurs as both polygyne and single queen nests. This study examined intra-caste size differences between both social forms of nests. Four polygyne and 13 single queen nests were collected from counties in Florida and Georgia. All single queen nests were one season old, whereas polygyne nests were at least 2 years old. The latter had significantly more workers per nest (p 0.72), whereas the lowest positive correlations were obtained between weight and all other measures of size (r < 0.64). Gynes of both social forms differed significantly in weight (p < 0.001) and thorax length (p < 0.04), whereas workers differed significantly for all six measures of size (p < 0.04 to p < 0.001).