Association between host wing morphology polymorphism and Wolbachia infection in Vollenhovia emeryi (Hymenoptera: Myrmicinae)

Abstract

Many eusocial insects, including ants, show complex colony structures, distributions, and reproductive strategies. In the ant Vollenhovia emeryi Wheeler (Hymenoptera: Myrmicinae), queens and males are produced clonally, while sterile workers arise sexually, unlike other ant species and Hymenopteran insects in general. Furthermore, there is a wing length polymorphism in the queen caste. Despite its evolutionary remarkable traits, little is known about the population structure of this ant species, which may provide insight into its unique reproductive mode and polymorphic traits. We performed in-depth analyses of ant populations from Korea, Japan, and North America using three mitochondrial genes (COI, COII, and Cytb). The long-winged (L) morph is predominant in Korean populations, and the short-winged (S) morph is very rare. Interestingly, all L morphs were infected with Wolbachia, while all Korean S morphs lacked Wolbachia, demonstrating a association between a symbiont and a phenotypic trait. A phylogenetic analysis revealed that the S morph is derived from the L morph. We propose that the S morph is associated with potential resistance to Wolbachia infection and that Wolbachia infection does not influence clonal reproduction (as is the case in other ant species).