The first brood emerges smaller, lighter, and with lower lipid stores in the paper wasp Polistes jokahamae (Hymenoptera: Vespidae)

摘要

Workers and gynes (potential queens for the next spring) of temperate paper wasps are distinguishable based on their lipid stores a few weeks after emergence. However, it was not known whether the lipid stores of worker- and gyne-destined females differ at emergence. Newly emerged females of Polistes jokahamae were divided into three categories: the first brood, comprising worker-destined individuals that are nursed only by the queen; the second brood, comprising worker- and gyne-destined individuals that are nursed by the queen and workers and emerge before male emergence; and the third brood, comprising gyne-destined individuals that emerge after the emergence of the first males. The first brood produced smaller and lighter adults with lower lipid stores. These lipid stores were lower even after adjusting for head width, which suggests the presence of a preimaginal bias toward worker caste; such a bias was not detected in the second brood. After adjusting for head width, lipid stores increased with the wet mass in the second and third broods but not in the first brood, suggesting that the component proportion of lipid stores increased but that of some other nutrients decreased with increasing wet mass in the first brood. In addition, the head width, wet mass, and lipid stores (including lipid stores divided by the head width cubed) in the first brood increased with the emergence order, whereas the fatness (wet mass divided by the head width cubed) did not.