遮蔽行为对海刺猬摄食、生长和性腺性状的影响

海胆遮蔽行为对于海胆的生长和发育的影响目前还不清楚,在实验室条件下,研究了遮蔽行为对海刺猬(Glyptocidariscrenularis)摄食、生长和性腺性状的影响。实验设两个对照组和一个处理组:对照组为无任何遮蔽条件的空白组和以堆积砖块创造的黑暗空间来满足海胆的掩蔽行为的掩蔽组,遮蔽组则以菲律宾蛤仔(Ruditapes philippinarum)的贝壳作为遮蔽物来满足海胆的遮蔽行为。结果显示:遮蔽组的海胆周摄食量要显著大于掩蔽组(P<0.05),而空白组与遮蔽组和掩蔽组之间的差异不显著(P>0.05);各组海胆的存活率没有显著差异(P>0.05);空白组和遮蔽组海胆的壳径、壳高、体重要显著大于掩蔽组(P<0.05),而空白组和遮蔽组之间没有显著性的差异(P>0.05);空白组和遮蔽组的性腺湿重、性腺干重、性腺指数、壳湿重、壳干重、亚氏提灯湿重、亚氏提灯干重要显著大于掩蔽组(P<0.05),而空白组和遮蔽组之间没有显著性的差异(P>0.05);空白组的提灯指数要显著小于遮蔽组和掩蔽组(P<0.05),而遮蔽组和掩蔽组之间没有显著的差异(P>0.05)。结果证明,遮蔽和掩蔽行为对海刺猬生长及发育的影响是有差别的,掩蔽行为对海刺猬的生长与发育造成了负面影响,而遮蔽行为在一定的生活环境条件下不会对其生长造成影响。研究表明,海刺猬的遮蔽行为反映了其对外界不利环境条件的一种适应性,且这种行为对其生长和发育的影响与掩蔽行为有所不同。至于海刺猬遮蔽行为的进化选择压力,目前的研究还不足以下定论,需要进一步深入的研究。

Effects of the covering behavior on food consumption, growth and gonad traits of the sea urchin Glyptocidaris crenularis

It is well known that the functions of the covering behavior of sea urchins include protection against predation, waves and avoiding over-exposure to light and particles. However, the effects of the covering behavior on fitness traits of sea urchins are not known. This lack prevents our understanding the selective pressure for the covering behavior of sea urchins. The evolutional drives of the covering behavior of sea urchins require studying the effects on fitness traits. The present study investigated the effects of covering behavior on food consumption, growth and gonad traits in comparison to the effects of the sheltering behavior in Glyptocidaris crenularis. Our study had three treatments: sea urchins with access to covering material (shells of the clam Ruditapes philippinarum), sea urchins with access to shelter (bricks) and sea urchins without access to shells or shelter. Food consumption, growth and gonad traits were measured. Food consumption of the sea urchins that covered themselves with shells was significant higher than that in the group with access to shelter (P<0.05). However, food consumption in the groups with shells or shelter was not significantly different from the group without shells or shelter (P>0.05). The three groups showed no significant difference in survival (P>0.05). Sea urchins in the groups with or without shells had a significantly higher test diameter, test height, wet body weight, wet gonad weight, dry gonad weight, gonad index, wet test weight, dry test weight, wet lantern weight and dry lantern weight than those with access to shelter (P<0.05). However, no significant difference of these traits was found between the groups with shells and without shell or shelter (P>0.05). The lantern index of sea urchins in the group without access to shells or shelter was significant lower than those with access to shells or shelter (P<0.05). There were no significant differences in the traits for the two groups (P>0.05). In the present study, we found negative effects of sheltering behavior of the sea urchins compared to the group with no access to shells or shelter. No such negative impacts were found on the individuals covering themselves with shells. The present study provides evidence on the differences between covering and sheltering behaviors. The effect of the covering behavior on growth and gonad traits were significantly different from those of the sheltering behavior in G. crenularis. The results of this study also indicate that the covering behavior represents an adaptation of G. crenularis in adverse environmental conditions. However, we should be aware that the present study is far from knowing the selective pressure of the covering behavior in G. crenularis. Further studies should be done to understand the evolutional drives of the covering behavior of G. crenularis.