Procambarus Clarkii Response To Two Kinds Of Environmental Heterogeneity And The Selection Of Shelter

procambarus clarkii is a kind of social animal which has social rank.The study of its survival environment will not only reduce disability and mortality,but also improve its biological function and adaptability.The paper mainly sets up the experiments from the three aspects:the heterogeneity of space environment,the heterogeneity of social environment and the shelter,in order to find out the best environment for living.The first experiment sets different special heterogeneity on the basis of different social heterogeneity.The death rate and growth length under the different conditions are compared.The statistics make the conclusions that,heterogenous social environment can extremely increase the mortality,and heterogenous special environment can promote growing.The results of experiments not only enrich the theory of social rank,but also provide guides in practice of species breeding.In the second experiment,comparing individuals with shelters or not by analyzing survival rate and growth length,we can get the conclusion that there was no significant difference in survival rate in earlier stage.At later stage,the survival rate of individuals with shelters was significantly higher than that of individuals without a shelter.The shelter can promote the growth of crayfish,but later the results of both two experimental groups are not significant.Presumably this is due to the fact that shelter has no ductility,can not provide more space.To some extent,shelter can inhibit the growth of crayfish.At the same time,the negative conservative strategy of lazy shrimp is also not conducive to the growth of crayfish.In the third experiment "the choice of shelter material",the crayfish were put into the rearing boxes with only PVC tubes,only scouring pad,and both the scouring pad and the PVC pipe material.The choice of two kinds of materials by crayfish were observed and recorded.We found that:crayfish are most likely to choose the scouring pad shelters,which is due to the tendency of touch and preference for more rough caves.What's more,the shelter made of scouring pad has the absorbability and can be used to mark the crayfish's own signals.Keeping the female crayfish staying in shelter for 48-72 hours,and then putting the non-chemical shelter(unoccupied)and the occupied shelter at both sides of the box,observing the first selection for the shelter.Other groups use the same method.We can get the result that crayfish are tend to choose shelters occupied by the same species.For the experiment of females,there is no significant difference between the choice of self and homosexual,homosexual and heterosexual shelters,but when it comes to the choice between self and male shelters,female crayfish tend to choose the male ones.For the experiment of males,there is no difference in choice.The "information" difference of signals in shelter can change the behavior of choice.Crayfish have a tendency to choose "marked" shelter,and females have a high tendency to choose males'.However,males need trade-offs in defensing,mating,aggression and so on,which are related to the initiative of male mating in the reproductive season.