|
Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences >
Peer-reviewed Journal Articles, etc >
SEASONAL AND INTER-SPECIES COMPARISON OF ASYMMETRY IN THE GENITAL SYSTEM OF SOME SPECIES OF THE OCEANIC COPEPOD GENUS METRIDIA (COPEPODA, CALANOIDA)
| Title: | SEASONAL AND INTER-SPECIES COMPARISON OF ASYMMETRY IN THE GENITAL SYSTEM OF SOME SPECIES OF THE OCEANIC COPEPOD GENUS METRIDIA (COPEPODA, CALANOIDA) |
| Authors: | Arima, Daichi Browse this author | | Matsuno, Kohei Browse this author →KAKEN DB | | Yamaguchi, Atsushi Browse this author →KAKEN DB | | Nobetsu, Takahiro Browse this author | | Imai, Ichiro Browse this author →KAKEN DB |
| Issue Date: | Dec-2015 |
| Publisher: | Brill Academic Publishers |
| Journal Title: | Crustaceana |
| Volume: | 88 |
| Issue: | 12/14 |
| Start Page: | 1307 |
| End Page: | 1321 |
| Publisher DOI: | 10.1163/15685403-00003485 |
| Abstract: | The seasonal and inter-annual changes in the asymmetry of female insemination and the male leg 5 of the planktonic calanoid copepods Metridia okhotensis and M. pacifica were investigated in the Okhotsk Sea. An inter-species comparison of both parameters was also carried out on seven Metridia species collected from oceans throughout the world. For M. okhotensis from the Okhotsk Sea, most of the females showed left-side insemination (annual average: 95.7%) and most of the males showed left-side asymmetry (99.7%) of the long inner process of the second exopodal segment in the fifth leg throughout the year. However, sympatric M. pacifica showed different ratios of asymmetry for female insemination and male morphotypes with a left : right = 1 : 2 ratio throughout the year. For the seven Metridia species from the global oceans treated in this study, ratios of asymmetry for female insemination and male morphotypes were correlated with each other. One-sided insemination (i.e., only left or only right insemination) was a common pattern for various Metridia species from global oceans, but their ratios varied by species. Previously, low hatching rates (29-68%) of eggs were reported for various Metridia spp. in laboratory experiments, but the reasons for these low rates were unclear. Because each spermatheca of Metridia spp. is connected to the oviduct on the same side, either left or right, this suggests that half of the eggs produced by unilaterally inseminated females remain unfertilized. The morphology of the genital structures and literature data of the egg hatching rates of Metridia spp. indicate that almost half of the eggs produced by females are not viable and are, thus, wasted. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/60532 |
| Appears in Collections: | 水産科学院・水産科学研究院 (Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 今井 一郎
|
