Territoriality is a common expression of territorial behavior. However, the territorial behavior of the swimming crab, Portunus trituberculatus, is not fully understood. In this experiment, an indoor camera system (an infrared camera, video recorder, monitor, light source, cylindrical experimental aquarium, shade cloth, and shelter) was used to explore the territory size, time allocation, and behavioral changes of the swimming crab. The crab's foraging type was determined according to their behavior under different prey densities. The crab's territorial behavior was evaluated using a “territorial behavior score (calculated according to the total number of territorial behaviors, defense time, the number of bouts, and the winning percentage of the initial crab).” With an in se in clam density, (1) the size of territory occupied by the crab decreased, the success rate of eviction, the proportion, and the number of active fights decreased, the prior residence effect gradually weakened, and the “territorial behavior score” decreased significantly; (2) feeding time and time spent occupying shelter increased, whereas the defense time (animal patrols and expelling of intruders) and free time (animal is motionless) decreased when the intruder was absent. The time occupying the shelter did not change in the intruder's presence. Comparing our results with previous studies, we found that the foraging type of swimming crab is an energy maximizer (spending more time feeding after consuming enough net energy for its activities). Increasing the prey density can weaken the territoriality of swimming crab. To our knowledge, this is the first research on the territorial behavior of the swimming crab. Our results enrich the literature on the territorial behavior of crustaceans and provide a basis for predicting population size changes in Portunus trituberculatus.

领土性是领土行为的一种常见表达。然而，游泳蟹Portunus trituberculatus的地域性，尚未完全了解。在此实验中，使用室内摄像头系统（红外摄像头，录像机，监视器，光源，圆柱形实验水族箱，遮阳布和庇护所）来探索螃蟹的区域大小，时间分配和行为变化。螃蟹的觅食类型是根据它们在不同猎物密度下的行为来确定的。使用“领土行为得分（根据领土行为的总数，防御时间，回合次数和初始螃蟹的获胜率计算）来评估螃蟹的领土行为。” 随着蛤密度的增加，（1）螃蟹所占领土的面积减小，驱逐成功率，主动打斗的比例和数量减少，在先居住效应逐渐减弱，“地域行为得分”显着下降。（2）进食时间和在避难所所花费的时间增加了，而没有入侵者时的防御时间（动物巡逻和驱逐入侵者）和自由时间（动物静止不动）则减少了。入侵者在场的时间并没有改变。将我们的结果与以前的研究进行比较，我们发现觅食型游泳蟹是一种能量最大化器（在消耗足够的净能量进行活动后，它会花费更多的时间进食）。增加猎物密度会削弱游泳蟹的地域性。就我们所知，这是对游泳蟹地域行为的首次研究。三疣梭子蟹。