金乌贼雄性规格和社群数量对求偶与交配行为的影响

为探讨不同规格雄性金乌贼(Sepia esculenta)在求偶交配过程中的竞争及优势等级,采用实验生态学方法,在室内可控条件下分别设置1L1S组、1L2S组和1L4S组(L和S分别表示大规格雄性和小规格雄性,数字表示实验中雄性金乌贼数量),连续摄像观察和记录金乌贼的繁殖行为。结果显示:(1)繁殖过程中金乌贼具有明显的领域行为和护卫伴游行为。(2)随着群体中小规格雄性比例的增加,处于优势地位的大规格雄性个体的优势等级发生变化,主要表现为大规格雄性护卫伴游时间、成功交配次数逐渐减少,而小规格雄性护卫伴游时间、成功交配次数逐渐增多。(3)当群体中小规格雄性较少时,大规格雄性常常主动攻击小规格雄性,而当小规格雄性数量远大于大规格雄性时,小规格雄性主动向其他雄性发起攻击,以争取护卫权和交配权。研究表明,雄性金乌贼的规格和数量对于求偶竞争以及交配行为具有显著影响。随着繁殖群体中小规格雄性增多,大规格雄性成功交配次数逐渐降低。1L4S组成功交配次数稍高于1L2S组,显著高于1L1S组(P0.05)。人工苗种繁育过程中选择合适规格的雄性亲体和合理的雌雄比例,对提高金乌贼繁殖效率具有重要意义。

Effects of male size on the reproductive behavior and competition of Sepia esculenta

Sepia esculenta is a single-season breeder, which dies soon after reproduction. It is important to study the reproduction of S. esculenta. Male size plays an important role in mating competition. This study set out to explore the differences in courtship, competition, and mating behavior between different size male S. esculenta. An experiment with three treatment groups (1L1S, 1L2S, and 1L4S; where L and S represent large- and small-size males, and the number represents the amount of experimental male S. esculenta with each size.) was conducted. A video camera was used to record the reproductive behaviors of S. esculenta during the experimental process. Four different types of behaviors (mate behavior, aggressive behavior, submissive behavior, and accompany behavior) were analyzed over a 2-day period. It was shown that S. esculenta exhibited clear territorial and guarding behaviors during the breeding season. With the increasing proportion of smaller males in the treatment groups, the dominance hierarchy of the large-sized males changed, in which the duration of guarding behaviors and number of successful mating attempts decreased among the large males, while those for the smaller males increased. When there were not enough smaller males in the treatment group, the larger males often actively attacked the smaller ones. When the number of smaller males increased, they actively attacked the larger males to strive for the chances of guarding and mating. The results show that male size has a significant influence on competition and mating behaviors, which potentially corresponds with the determination of male S. esculenta sizes and male-female ratio during breeding. These results may improve the breeding efficiency and contribute to the stock enhancement and development of S. esculenta.