01486nas a2200133   4500008004100000245009700041210006900138260000800207300001100215490000700226520105400233100001601287856004901303       2000                        eng d00aPossible Removal of Rival Sperm by the Elongated Genitalia of the Earwig, Euborellia plebeja0 aPossible Removal of Rival Sperm by the Elongated Genitalia of th  cJul  a667-720 v173 aSperm displacement is a sperm competition avoidance mechanism that reduces the paternity of males that have already mated with the female. Direct anatomical sperm removal or sperm flushing is known to occur in four insect orders: Odonata, Orthoptera, Coleoptera and Hymenoptera. In a fifth order, Dermaptera (earwigs), I found that the virga (the elongated rod of the male genitalia) of Euborellia plebeja seems to be used to remove rival sperm from the spermatheca (a fine-tubed female sperm storage organ). In this species, copulation lasted on average 4.6 minutes, during which time the male inserted the virga deep into the spermatheca, and then extracted it ejaculating semen from the opening of the virgal tip. The extraction of virgae (with its brim-like tip) appeared to cause removal of stored sperm in the spermatheca. The virga was as long as the body length of males, and the spermatheca was twice the female body length. The long length of the spermatheca and the possible removal function of the virga may select for virgal elongation.1 aKamimura, Y  uhttps://worldodonata.myspecies.info/node/26901712nas a2200145   4500008004100000245013900041210006900180260000800249300000800257490000700265520120900272100002001481700001601501856004901517       2006                        eng d00aDifferentiation of the dragonfly genus Davidius (Odonata: Gomphidae) in Japan inferred from mitochondrial and nuclear gene genealogies0 aDifferentiation of the dragonfly genus Davidius Odonata Gomphida  cJan  a1-80 v233 aTo infer the differentiation of Japanese Davidius dragonflies, we investigated the genealogies of the mitochondrial cytochrome oxidase subunit I gene (COI) and the nuclear ribosomal RNA gene region encompassing 18S, ITS1, 5.8S, and ITS2 sequences for three species endemic to Japan–Davidius nanus, D. fujiama, and D. moiwanus–as well as D. lunatus from the Korean Peninsula. According to the mitochondrial and nuclear gene genealogies, D. nanus and D. moiwanus are closely related and are sister to the continental species D. lunatus, whereas D. fujiama differentiated from an ancestor of the other three species. Although the mitochondrial DNA data did not resolve the relationships between D. nanus and three D. moiwanus subspecies, the nuclear DNA data indicate the monophyly of D. moiwanus and its subspecies. The nuclear gene genealogy suggests that isolated wetlands used by larval D. moiwanus derive from the ancestral riverine habitats of D. nanus and other Davidius species. The COI sequence divergence among local populations was much greater in D. moiwanus than in D. nanus, which may be the result of differences in the dispersal ranges associated with the habitat types of these species.1 aKiyoshi, Takuya1 aSota, Teiji  uhttps://worldodonata.myspecies.info/node/246