Traumatic insemination (TI), an extraordinary copulation strategy, is most prevalent in cimicoid true bugs (Insecta: Hemiptera) among invertebrates including insects. Here, we resolved the evolutionary history of TI and the females’ adaptations by conducting molecular phylogenetic analyses and comparative studies based on the phylgenetic relationships. We found a sister group relationship of Curaliidae + Lasiochilidae, which are the only groups among Cimicoidea not likely engaged in TI. Divergence time estimates revealed that TI is a behavior of antiquity that first evolved in the Early Jurassic 188Mya (95% highest posterior density = 157 – 221). Furthermore, ancestral character state reconstructions indicated that TI evolved only once from standard insemination in Cimicoidea. The results revealed that only TI is correlated with PS among the biological traits, and that evolutionary acquisition of PS was driven by selection of TI. Additionally, we found that not only are the three types of PS homoplastic to each other, but also that each of types could not be a homologous feature despite of same terminology, which suggests convergent evolution of the females’ morphology have occurred as females were adapting to TI.

• Sunghoon Jung(Research Institute for Agricultural and Life Sciences, Department of Agricultural Biotechnology, Seoul National University)
• Ondřej Balvín(Department of Zoology, Faculty of Science, Charles University)
• Kazutaka Yamada(Tokushima Prefectural Museum)
• Seunghwan Lee(Research Institute for Agricultural and Life Sciences, Department of Agricultural Biotechnology, Seoul National University)