Simultaneous spawning by female stream goby Rhinogobius sp. and the association with brood cannibalism by nesting males.
A laboratory experiment was conducted by varying the undersurface area of nesting substratum and the number of females in an experimental tank to elucidate the determinants of the mating pattern in the stream goby, Rhinogobius sp. cross-band type. Males with larger nests tended to attract two or more females to their nest in a tank. Moreover, males spawned simultaneously with multiple females and entire brood cannibalism by males was rarely observed under a female-biased sex ratio. When males spawned with a single female with low fecundity, however, entire brood cannibalism occurred at a high frequency, suggesting that a male guarding a nest with fewer eggs consumes the brood. Therefore, spawning behaviour of females that leads to a large egg mass would decrease the risk of entire brood cannibalism. In this species, simultaneous spawning by multiple females in a nest serves as a female counter-measure against entire brood cannibalism. These results suggest that a conflict of interest between the sexes through brood cannibalism is a major determinant of simultaneous spawning.
Hokkaido National Fisheries Research Institute, Fisheries Research Agency, 116 Katsurakoi, Kushiro, Hokkaido, 085-0802, Japan.
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S
Ito
Department of Biology, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan.
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Iwao
Department of Biology, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan.
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Sakata
Department of Biology, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan.
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Inoue
Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan.
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Omori
Department of Biology, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan.
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Yanagisawa
D000818:Animals; D002190:Cannibalism; D052284:Clutch Size; D005260:Female; D008297:Male; D009425:Nesting Behavior; D010063:Ovum; D010473:Perciformes; D012098:Reproduction; D045483:Rivers; D012744:Sex Ratio; D012726:Sexual Behavior, Animal
Rhinogobius; filial cannibalism; mating pattern; parental care; reproductive success