兴凯刺鳑鲏形态特征的两性异形和雌性个体生育力

Sexual Dimorphism in Morphological Traits and Female Individual Fecundity of Acanthorhodeus chankaensis Dybowsky

本研究测量了兴凯刺鳑鲏成体的体长、体高、头高、头长、头宽、吻长、眼径、眼间距、眼后头长、尾柄长、尾柄高、尾鳍长、背鳍基前距、背鳍基长、腹鳍基前距、腹鳍臀鳍间距和体重等17个形态学指标以及雌体的怀卵数量。结果显示,兴凯刺鳑鲏雌性个体和雄性个体体长差异不显著,特定体长的雌性个体的头长、眼后头长、眼径、尾鳍长和背鳍基长显著小于雄性个体,而体高、尾柄长、腹鳍基前距、腹鳍臀鳍间距和体重显著大于雄性个体。两性间其它局部特征不存在显著的差异。多元回归分析表明,兴凯刺鳑鲏的怀卵数量与体重和体高呈显著的正相关。雌性主要通过个体体重的增长以及腹腔体积(体高)的增加来提高个体生育力,增加繁殖输出。性选择、生育力选择、生态环境和食物营养状况影响兴凯刺鳑鲏两性异形的进化。

We measured the sexual dimorphism in seventeen morphological traits, including body length, body depth, head height, head length, head width, snout length, postorbital head length, eye diameter, interorbital width, caudal peduncle length, caudal peduncle depth, caudal fin length, dorsal fin precoxal length,dorsal fin coxal length, dorsal fin spacing, pelvic fin precoxal length, space between pelvic fin and anal fin and body mass of Acanthorhodeus chankaensis Dybowsky in Lishui, Zhejiang Province. The results showed that there was no significant difference in the body length between males and females of A. chankaensis. Adult females of A. chankaensis were significantly shorter than adult males in head length, postorbital head length, eye diameter, caudal fin length and dorsal fin coxal length, while adult females were longer than adult males in the body depth, caudal peduncle length, pelvic fin precoxal length, space between pelvic fin and anal fin and body mass fter accounting for body length. There was no apparent sexual difference in the other morphological traits. The linear regression showed that the individual fecundity was positively related with body length and body mass. It indicated that adult females increase the individual fecundity through increasing the body mass and capacity of abdominal cavity, thus increasing reproductiveoutput. The evolution of sexual dimorphism in A. chanleaensis is affected by sexual selection, fecundity selection, environment and nutrition of food.