Social parasitism behavior between two species of edible wasps in China.

We reported the social parasitism behavior between Vespula structor and Vl. flaviceps for the first time. These two Vespula species are both popular edible wasps in southwest China. Such a nest with these two mixed Vespula species in their natural state was found in the field, and observations both in situ and in doors were performed. Workers of the two Vespula species have distinct different looking but possess similar antennal sensilla. Mitochondrial DNA analysis proved these two Vespula were indeed two different species, with genetic difference of 14%. The queen observed in the nest belongs to Vl. structor which was supported both from morphology and DNA. The larvae collected during nest dissecting could not be distinguished which species they belong to, but DNA analysis proved that they were all Vl. structor individuals. Combined the behavior observation with the DNA data, we concluded that it was the queen of Vl. structor encroached on the nest of Vl. flaviceps, killed the queen of Vl. flaviceps, enslaved the workers in the nest, laid its own eggs, and gradually established the population of Vl. structor. Phylogenetic analysis based on complete mitochondrial genomes showed that they are close, and the Vl. structors was the more ancient species in evolution. In this case of wasp parasitism, the relatively ancient species Vl. structors parasitized the younger species Vl. flaviceps, suggesting that the social parasites (Vl. structor) were not evolved from their host (Vl. flaviceps), which rejected the Emery's rule in its strict sense. [ABSTRACT FROM AUTHOR]