| Abstract: | Bombus terrestris (L.) (Hymenoptera: Apidae, Apinae, Bombini) has been introduced to Japan and became the dominant bumblebee in some areas, replacing native species. To implement an effective eradication program, the attributes responsible for establishment of the species must be better understood. Because body size has frequently been related to reproductive success in female insects, I examined the effect of B. terrestris queen size during hibernation, nest founding, and reproduction stages. Queens exhibited clear variation in size. Foundresses were significantly larger than gynes, indicating that larger queens may have an advantage over smaller ones in surviving hibernation. The over‐representation of queens with pollen at larger sizes suggested that larger queens may also have an advantage over smaller ones in nest founding. On the other hand, foundress size was not significantly associated with reproductive output. The number of collected foundresses in this study was not sufficient to draw a clear conclusion but factors other than foundress size may also play an important role in determining reproduction. In addition, gyne size increased significantly during the 4‐year survey. Because large queens have an advantage during hibernation, increased body size may increase the number of hibernating queens that survive, allowing them to outcompete native bumblebees. |
