cost of flight: a role in the Polistes dominulus invasion

Polistes dominulus is a primitively eusocial paper wasp from Mediterranean Europe that is invasive to North America. In Eastern North America, P. dominulus is in competition with P. fuscatus. One reason for the success of P. dominulus is that their colonies produce more reproductive offspring than P. fuscatus colonies. A partial explanation for this difference is that P. dominulus foundresses make more foraging trips in the pre-worker period, which likely helps them to rear workers more quickly. In comparing the species, we found that P. dominulus had a lower absolute flight metabolic rate, but that P. fuscatus had a lower mass-specific flight metabolic rate. In addition, in P. fuscatus, wingloading correlated with flight metabolic rate, but that this was not the case in P. dominulus. This suggests that P. fuscatus is not able to transport large loads inexpensively. Therefore, the lower overall cost of transport of P. dominulus may provide an advantage by allowing the foundresses to make more relatively efficient foraging trips. In addition, we compared time in flight by P. dominulus and P. fuscatus over a range of temperatures and found that while P. fuscatus flew well over a broad range of temperatures, P. dominulus had a relatively narrow range of optimal temperatures for flight (30–33°C). These differences may help explain both the success and the limitations of the P. dominulus invasion.