曼氏无针乌贼(Sepiella japonica)繁殖期行为谱特征的研究

自然海域中曼氏无针乌贼产卵亲体性成熟提前和小型化现象明显,这可能是一种适应性进化,人工干预背景下曼氏无针乌贼繁殖期行为的动态变化值得关注。2020年4-6月室内采用聚焦个体扫描法和定点连续记录法分别观察和记录了曼氏无针乌贼繁殖期的行为活动,并按其生活习性和行为的生物学功能等进行系统化分类,构建了繁殖期行为谱。结果表明,曼氏无针乌贼繁殖期行为谱主要包括三大类12种行为：（1）游泳行为主要分为前进和后退,繁殖期的雌性多处于静潜水底或静浮水中的状态;（2）捕食行为主要分为发现、定位、捕捉和咀嚼等系列动作,曼氏无针乌贼能够快速感知周围17.0-36.0 cm范围内的饵料,捕捉的有效距离为8.0-22.0 cm,能在2.0-10.0 s内完成对饵料的高效捕获;（3）繁殖行为复杂,主要分为求偶、伴游、交配、产卵等,其中求偶行为体现在雄性对雌性的自我展示、追逐配对和争斗护卫等过程,雄性在争斗护卫和伴游过程中的护雌行为尤为激烈。曼氏无针乌贼交配时采用"头对头"的方式,平均交配持续时间42.9 s。曼氏无针乌贼对产卵附着基有选择性且偏好于最初的附卵物,卵群对雌性产卵行为有诱导和刺激作用,每次产卵到附卵过程平均用时108.6 s。曼氏无针乌贼繁殖期行为谱特征的研究可为后续曼氏无针乌贼行为机制和基于全生活史的资源保护等方面提供理论依据。

STUDY ON THE CHARACTERISTICS OF BEHAVIOR ETHOGRAM IN REPRODUCTIVE PERIOD OF SEPIELLA JAPONICA

Miniaturization and sexual prematurity of spawning parents of spineless cuttlefish Sepiella japonica become more obvious in natural stocks due probably to its adaptive evolution, thus the dynamic changes in breeding behavior of the species under artificial intervention shall be paid with attention. From April to June in 2020, we observed and recorded the breeding behaviors of S. japonica by individual-focused scanning and stationary continuous recording in laboratory, systematically classified the behaviors in living habit and biological function, and constructed a breeding ethogram. Twelve behaviors were recognized and could be classified into three categories in the breeding period of S. japonica, i.e., swimming, feeding, and breeding. The swimming behaviors were mainly moving forward and backward, and females often stayed still at the bottom or floated. The feeding behaviors were composed of a series of actions such as searching, locating, capturing, and chewing. S. japonica could quickly sense the baits within a range of 17.0-36.0 cm, and capture swiftly in 8.0-22.0 cm in 2.0-10.0 seconds. The breeding behaviors were more complicated, and included courting, escorting, mating, and spawning, etc. The courting was mainly males showing off to females, chasing and mating, fighting and guarding. The guarding was more frequent than fighting to escort and protect females. Males and females mated in a head-to-head manner, and the average mating time was 42.9 s. S. japonica laid eggs onto the attached substrate after mating preferable to the first attaching place. Egg clusters could induce or stimulate the spawning. The average time from spawning to egg-attachment was 108.6 s. This study on ethogram characteristics of S. japonica during breeding period provided a theoretical basis for the subsequent behavior mechanism and resource conservation in the whole life cycle of the species.