三疣梭子蟹螯足断肢及再生对摄食和攻击行为的影响

Effects of chelicerae autotomy and regeneration on feeding and aggressive behaviors of swimming crab(Portunus trituberculatus)

为研究螯足断肢及再生对三疣梭子蟹(Portunus trituberculatus)摄食和攻击行为的影响,以体质量为(18.34±2.56)g(C期)的三疣梭子蟹为试验对象,采用高温胁迫断肢法,设置对照组(无断螯组)、断一螯组和断两螯组,测定了螯足断肢及再生后蟹的体质量、全甲长、全甲宽、体高及摄食量,计算断肢和再生前后的增重率、形态指标增长率及摄食率等指标,并采用EthoVision XT行为跟踪系统观察了螯足断肢及再生前后蟹的摄食选择性、摄食能力和攻击性行为的变化。结果表明:与对照组相比,断螯组三疣梭子蟹的体质量增长率略有下降(P>0.05),而断两螯组蟹的全甲宽、全甲长及体高的增长率则显著下降(P<0.05);断螯组三疣梭子蟹对花蛤肉及杂鱼的摄食率略有降低,再生各组间摄食率相似,但与对照组均无显著性差异(P>0.05);断两螯组和再生两螯组蟹均不能打开寻氏肌蛤,且与对照组间有显著性差异(P<0.05);断螯及再生后蟹的摄食选择性较对照组显著改变(P<0.05);随着螯足断肢数目的增多,断螯组蟹的争斗延迟时间呈下降趋势,而争斗持续时间、移动速度、移动距离及争斗强度则呈上升趋势,其中,断螯组蟹的争斗持续时间及争斗强度较对照组蟹显著降低(P<0.05)。研究表明,螯足断肢降低了三疣梭子蟹幼蟹的体质量和形体指标增长率,减少了幼蟹对花蛤肉和杂鱼的摄食率,螯足断肢及再生改变了幼蟹的摄食能力及摄食选择性,且断螯后幼蟹的攻击能力也减弱。

In order to study the effects of chelicerae autotomy and regeneration on the feeding and aggressive behaviour of swimming crab(Portunus trituberculatus),the method of high-temperature stress chelicerae autotomy was established in swimming crab with body weight of(18.34±2.56)g(phase C in molt).The body weight,total carapace length,total carapace width,body height,feeding rate,weight growth rate,morphological indicators,and growth rate were measured in swimming crab(no cheliped autotomy,control group),one cheliped autotomy group and two chelipeds autotomy group after chelicerae autotomy and regeneration.The changes in feeding selectivity,feeding ability and aggressive behaviour were observed in the swimming crab before and after autotomy and regeneration by EthoVision XT behavioural tracking system.The results showed that the swimming crab had slight decrease in growth rate of body weight in the cheliped autotomy groups compared to the control group(P>0.05),and significant decrease in the growth rate of total carapace width,total carapace length and body height in the two chelipeds autotomy group(P<0.05).There was slight decrease in feeding rate of clam meat and trash fish in the autotomy groups compared with that in the control group,with similar feeding rate among the regeneration groups,without any significantly different(P>0.05).Both two cheliped autotomy groups and two cheliped regeneration groups was not able to open Musculus senhousei,with significant difference from the control group(P<0.05).The swimming crab with amputated and regenerated chelicerae changed the feeding preference significantly compared with the swimming crab in the control group(P<0.05).The fight delay time was shown to be decreased,in steady of the fight duration,fight moving speed,fight moving distance and fight intensity tended to be increased in cheliped autotomy group,as the number of chelicerae autotomy increased,with the maximal significant difference in fight duration and fight intensity in cheliped autotomy group compared with that in the control group(P<0.05).It was found that cheliped autotomy led to reduce the growth rate of body weight and morphological indicators in the juvenile swimming crab.The food ingestion rate on clam meat and trash fish and aggressive ability were decreased after cheliped autotomy in the juvenile swimming crab,without effect of the regeneration of the chelicerae on the feeding rate of clam meat and trash fish.