不同实验生态环境对海刺猬遮蔽行为的影响

Effects of different ecological environments in the laboratory on the covering behavior of the sea urchin Glyptocidaris crenularis

研究了较长时间生活在3种不同实验遮蔽条件下海刺猬(Glyptocidaris crenularis)的遮蔽行为特点。结果表明:不同生活环境下海刺猬都保持着遮蔽行为。生活在以贝壳作为遮蔽材料环境下(遮蔽组)和以砖块作为掩蔽材料环境下(掩蔽组)的海刺猬初次遮蔽耗时要显著短于生活在无遮蔽(或掩蔽)材料环境下(空白组)的海刺猬(N=3,P<0.05)。3组海刺猬用于遮蔽的贝壳总数和有遮蔽行为的海刺猬总数都呈现先增加后趋于平稳的趋势。掩蔽组有遮蔽行为的海刺猬总数要显著多于遮蔽组和空白组(P<0.05),后两者差异不显著。3组海刺猬用于遮蔽的贝壳总数差异不显著(P>0.05)。海刺猬遮蔽时对两种贝壳(菲律宾蛤仔和贻贝)存在显著的选择差异(P<0.05)。生活环境中一段时间内遮蔽物的缺失并不会使其失去这种行为,但是会在一定程度上影响该行为的强度。因此,光照很可能是海刺猬遮蔽行为的一个进化压力,该行为也许只是作为一种避光策略。海刺猬对遮蔽材料具有显著的选择性,这可能与遮蔽材料自身特征和海刺猬的生理状态相关。

Covering behavior is a common but strange behavior in the sea urchin Glyptocidaris crenularis.The evolutionary basis of the behavior remains largely unknown and unclear.We investigated the effects of different ecological environments in the laboratory on the characteristics of the covering behavior of the sea urchin G.crenularis.We used three different environments: with shells(covering group),with brick(sheltering group) and without covering materials(blank group).After seven months culture in each environment,we observed the covering behavior of the sea urchin G.crenularis using shells of two species of bivalve molluscs(Ruditapes philippinarum and Mytilus edulis) as potential covering material.The results showed that sea urchins in covering and sheltering groups picked up a shell and placed it onto its upper surface in a significantly shorter time than those in the blank group(P<0.05).The number of sea urchins displaying covering behavior and the number of shells used for covering over time increased to a plateau for all three groups.The number of sea urchins displaying covering behavior reached the plateau at 40,40 and 160 minute in the covering,blank and sheltering groups,respectively.The number of shells used for covering in covering,blank and sheltering groups reached plateau at 40,40 and 120 minutes,respectively.Significantly more sea urchins displayed the covering behavior in the sheltering group than the other two groups(P<0.05).However,there was no significant difference between the other two groups(P>0.05).The number of shells used for covering was similar for the three groups(P>0.05).However,the species of mollusk shell sea urchins used to cover differed significantly(P<0.05).The percentage of sea urchins that used only one mollusc shell species as the covering material reached 78%.Long exposure to light could influence the covering behavior of G.crenularis.The degree of covering behavior decreased in sea urchins that were exposed to light for a period of time.Light may be a selective pressure for the covering behavior.The covering behavior may be the result of a long-term evolutionary process because all sea urchins maintained the covering behavior in the different environments.Glyptocidaris crenularis could not loss the covering behavior due to the lack of covering material in a period of time,although the intensity and degree of the covering behavior could be influenced.Glyptocidaris crenularis showed obvious selectivity to the type of covering material.This may be related to the characteristics of the covering material and the physiological state of the sea urchins.We think that the covering behavior is possibly one of the strategies to avoid light.Other strategies to avoid light could be selected by G.crenularis if habitats in the field lack covering and sheltering materials.The covering behavior of G.crenularis can be influenced by various factors.The comprehensive effects of these factors on covering behavior and the effect of covering behavior on physiology in G.crenularis needs further study.