Thelytokous parthenogenesis in the exotic dacetine ant Strumigenys rogeri (Hymenoptera: Formicidae) in Taiwan

Only recently has it become clear that several species of eusocial hymenopterans regularly reproduce by thelytokous parthenogenesis, that is, the production of diploid female offspring by unmated females. This phenomenon suggests that parthenogenetic reproduction might be advantageous to organisms under certain environmental conditions. Here the occurrence of asexual reproduction is reported for the first time in the dacetine ant, Strumigenys rogeri, at least for the focal populations in Taiwan. Virgin queens of S. rogeri maintained with several workers produced both workers and young queens from unfertilized eggs under laboratory conditions in as short as 39 days, whereas workers were strictly sterile as no spermatheca was discovered after dissection. Combined with additional evidence (i.e. absence of males in field colonies), queen thelytoky is confirmed. Such a reproductive mode and short development time may jointly help explain the success of this tramp ant species in Taiwan and elsewhere. The occurrence of asexual reproduction is reported for the first time in the dacetine ant Strumigenys rogeri, at least for the introduced populations in Taiwan. In laboratory conditions, virgin queens of S. rogeri were found capable of producing both workers and young queens via thelytokyous parthenogenesis. Along with a finding that both female castes could be produced asexually in as short as 39 days, thelytokyous parthenogenesis may partially contribute to the success of S. rogeri as a worldwide tramp ant species.