No gene flow between wing forms and clonal reproduction by males in the long-winged form of the ant Vollenhovia emeryi

In Vollenhovia emeryi, males produced by the short-winged queens (S males) have the same genotype of genomic opsin gene as the long-winged queens (L queens) rather than the cohabiting S queens. This fact suggests that either one of the following two events might have occurred, (1) a recent gene flow between the S males and the L queens or (2) a past hybridization event between them. In order to test these hypotheses, we analyzed the nuclear genome and the mitochondrial DNA of L males, L queens, and sperm from the L queens' spermathecae. Results showed that genotype frequencies differed significantly between L males and L queens and between the sperm and L queens. Mitochondrial haplotypes of the sperm were consistent with their queen. These indicate that (1) queens of the L form mated only with the males that have been produced by L queens, and thus there is no gene flow from S males to L queens; (2) males of the L-form clonally produce sons as males of the S-form do; and (3) genotype similarity between S males and L queens indicates a past hybridization event.