Effect Of Predation Pressure On Parental Care Behavior Of Plestiodon Chinensis

Parental care,defined as any form of behavior that increases the fitness of offspring,is an important feature of most endotherms and a number of ectotherms.Parental care is an important part of animal reproduction,development,family and social evolution.Predation pressure is an important factor that drives the evolution of many animal characteristics.Due to the lack of research,the relationship between predation pressure and parental care evolution is still unknown.Chinese skink(Plestiodon chinensis)is a species of skink lizard widely distributed in south China.It has typical brooding behavior and is an ideal model for studying the evolution of parental care behavior.Here,we used P.chinensis as the object of experimental studies and divided them into low pressure group(box with a male P.chinensis),high pressure group(box with a snake,Lycodon rufozonatus),normal breeding group(control),postpartum eggs removed group,postpartum parent removed group and non-reproductive group to experiment with different degree of predation pressure processing.Animals were fed in the same laboratory environment.The costs of parental care to the parent and the benefits of parental care to the offspring were assessed by measuring the parent's daily activities(out-of-nest activity time,accumulated food consumption during the study period)and subsequent growth and survival(changes in body mass before egg laying,during hatching,and in the following two months),the offspring's phenotype(hatching success rate,locomotor performance)and subsequent growth and survival(growth rate and survival rate in outdoor enclosure for two months).At the same time,we randomly selected some female individuals of parental care period,and assessed the potential impact of predation pressure on animal intestinal microbiota by measuring the intestinal microbiota diversity of parental care period.The main results are as following:1.The results of this study show that post-oviposition females would decreased the time for out-of-nest activity and consumed less food after laid eggs.The females of post-oviposition removed and non-reproductive group had longer time for out-ofnest activity and higher food consumption than those of other groups.There was no significant difference in within-nest time and food consumption between the pressure group and the control group;there was significant difference in maternal body mass between the groups.There were also differences in maternal body mass among different groups.2.The hatching success rate and hatchling survival rate of the simulative pressure group were lower than those of the control group.Compared with other care groups,the hatching success rate and hatchling survival rate of Postpartum eggs removed were much lower than those of other care groups.There was no significant effect of predation pressure on the locomotor performance of hatchlings.3.The microbial communities of the intestinal feces of the mothers in different treatment groups were classified and identified,and a total of 19 phylum and 129 genus of different microbial species were detected.Although there were some differences in the dominant species of intestinal microorganisms in different treatment groups,the results showed that there was no significant difference in the intestinal microbiota diversity of each treatment group.4.This study quantified the parental care costs and offspring benefits of P.chinensis.Under the control of predation pressure,it was found that the cost and benefit of parenting did not correspond completely,but the benefit of parental care decreased with the application of predation pressure.Therefore,effectively verifying the predation pressure in the environment was an important factor affecting the evolution of parental behavior of P.chinensis.