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Titolo:
Female-biased operational sex ratio of sexual host fish in a gynogenetic complex of Carassius auratus
Autore:
Hakoyama, H; Matsubara, N; Iguchi, K;
Indirizzi:
Kyushu Univ, CREST, JST,Fac Sci, Dept Biol, Fukuoka, Japan Kyushu Univ Fukuoka Japan CREST, JST,Fac Sci, Dept Biol, Fukuoka, Japan Natl Res Inst Fisheries Sci, Ueda, Nagano, Japan Natl Res Inst Fisheries Sci Ueda Nagano Japan s Sci, Ueda, Nagano, Japan
Titolo Testata:
POPULATION ECOLOGY
fascicolo: 2, volume: 43, anno: 2001,
pagine: 111 - 117
SICI:
1438-3896(200108)43:2<111:FOSROS>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
POECILIOPSIS PISCES-POECILIIDAE; RED QUEEN HYPOTHESIS; MAINTENANCE; COEXISTENCE; PARASITISM;
Keywords:
Carassuis auratus; coexistence; gynogenesis; population structure; female-biased sex allocation hypothesis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Hakoyama, H Hokkaido Natl Fisheries Res Inst, 116 Katsurakoi, Kushiro 0850802, Japan Hokkaido Natl Fisheries Res Inst 116 Katsurakoi Kushiro Japan 0850802
Citazione:
H. Hakoyama et al., "Female-biased operational sex ratio of sexual host fish in a gynogenetic complex of Carassius auratus", POPUL ECOL, 43(2), 2001, pp. 111-117

Abstract

To study the coexistence of sexual and gynogenetic forms, we examined the population structure of a gynogenetic complex of the Japanese crucian carp,Carassius auratus Temminck et Schlegel, during the April-June reproductiveseason by collecting 1225 mature fish that migrated from Lake Suwa to a tributary river for spawning. There were more sexual fish (about 80%) than gynogenetic fish in this complex, and the operational sex ratio in the sexualform was female biased (males were about 20%). Mean standard length and body weight of sexual females were larger than those of sexual males. Sex ratio was male biased in smaller fish (standard length, <8.5 cm) but female biased in larger fish (standard length, greater than or equal to8.5cm). We determined age by scale ring marks; the average age of sexual females was higher than that of males, but there was no significant difference in the average age between sexual and gynogenetic females. Sex ratio in the sexual form was more female biased for old than for young fish, and the mean size of sexual females was larger than that of males of the same age. The clear female-biased sex ratio and age difference between sexual females and males can be explained either by (1) higher mortality of males or by (2) female-biased sex allocation. The latter process reduces the disadvantage of sex and contributes to the coexistence of sexual and gynogenetic forms.

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Documento generato il 19/09/20 alle ore 09:11:36