摘要
两性个体的有效鉴别是曼氏无针乌贼高效繁育及养殖模式(如单性养殖)建立的基础。为研究曼氏无针乌贼主要形态指标及雌雄形态差异,测量了160只F_1代曼氏无针乌贼的19项可测量性状及13项标准化性状。采用聚类分析、主成分分析和判别分析方法研究了曼氏无针乌贼同生群两性间的形态差异。结果表明:两性间可测量性状和标准化性状各有10项有显著性差异(P<0.05);对标准化性状经过主成分分析和R-聚类分析均显示曼氏无针乌贼的两性的差异主要集中在辅助交配器官特征,头部特征,捕食器官和肥瘦特征以及体型特征等4个方面。在此基础上,通过逐步判别法从标准化性状中筛选出3项,即左3腕长/胴长、左4腕长/胴长及左触腕长/胴长,建立了雌雄的判别方程:雄性:F_1=223.42X_3+165.85X_4+7.951X_5–108.06;雌性:F_2=151.48X_3+92.71X_4+19.19X_5–60.38。所建立的判别方程,对样本群体的综合判别率达到95.00%。利用F_2代亲体测量数据对判别函数进行识别验证,综合判别率达到85.34%。在判别方程中的3个标准化性状中,左3腕长/胴长和左4腕长/胴长在两性亲体间均存在显著的差异(P<0.05),表明曼氏无针乌贼的雄性在性选择的作用下,交配器官存在显著差异。
To identify accurately the sex of Sepiella japonica in morphology is impotent for efficient breeding and aquaculture practice. We studied the main morphological parameters and the sexual differences. Nineteen measurable traits and 13 standard characters from 160 S. japonica of F1 generation were determined. Differences in sexual morphology were studied by cluster analysis method, principal component analysis, and discriminant analysis. The results show that there are 10 significant differences(P<0.05) that are mainly embodied in auxiliary copulatory organs, the head, predation organs, and body dimensions as revealed in principal component analysis and R-cluster analysis. Three traits in length were selected by stepwise discriminant analysis, i.e., the length of the third left tentacle/mantle, that of the fourth left tentacle/mantle, and that of the left tentacle length/mantle. Sexual discriminant equations were established for both genders, with which overall success of discrimination for the F1 samples reached 95%; and85.34% for F_2 generation.
引文