Relationships between body size and secondary sexual characters,and sperm characters in male Dolly Varden char (Salvelinus malma) |
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| Authors: | Toshiaki Yamamoto Noritaka Hirohashi Eiji Fujiwara Tatsuya Suzuki Hatsuna Maruta Hirotake Omiya Shigeru Kitanishi |
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| Affiliation: | 1. Department of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan;2. Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, Oki, Shimane, Japan;3. Documentary Channel Co. Ltd., Tsurugashima, Saitama, Japan;4. Planning Section, Minamifurano Town Office, Hokkaido, Japan;5. College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan |
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| Abstract: | In Salmonidae, subordinate males are exposed to higher risks of sperm competition than dominant males and thus are expected to improve the sperm characteristics (sperm concentrations, sperm velocity and sperm longevity). In this study, we investigated the relationships between body size and secondary sexual characters (breeding colour, hump height and snout length), and sperm characteristics of one‐year‐old (newly matured) Dolly Varden char. Small males displayed higher sperm concentrations than large males. Moreover, males with dull breeding colours, but not with lesser snout length and hump height, displayed an increased sperm velocity compared to males with bright colours, suggesting a trade‐off between sperm quantity and the investment in breeding colour. In addition, sperm longevity decreased as sperm swimming velocity increased. These findings indicate that small males with dull breeding colours improve the quantity and quality of their sperm to a great extent to enhance their chances of reproductive success. |
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| Keywords: | breeding colour Dolly Varden char secondary sexual characters sperm concentrations sperm longevity sperm velocity |
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