Parent-offspring Conflict In The Grey-backed Shrike

Parent–offspring conflict(POC)is an expression coined in 1974 by Robert Trivers.It is used to describe the evolutionary conflict arising from differences in optimal parental investment in an offspring from the standpoint of the parent and the offspring.PI is any investment by the parent in an individual offspring that decreases the parent's ability to invest in other offspring,while the selected offspring's chance of surviving increases.This study targets the Grey-backed Shrike(Lanius tephronot)that breed on the Tibetan Plateau.I try to use it to answer several key questions that affect the parentoffspring conflict between Gray-backed Shrike: 1)whether begging signal is true;2)the reason that may affect the parental care;3)Nestling response to parental care strategies.This study collected plateau-grown Gray-backed Shrike life history data from the Xiongse River Valley near Qushui County,Lhasa,Tibet,from 2015 to 2017,including: reproductive cycle,laying date,clutch size and brood size,brood period,fledging number,newborn weight,fledging weight,etc.,and behavioral data: data related to parent supply and offspring begging behavior,and use SPSS(version 20.0)to construct a generalized linear mixture The statistical analysis of generalized linear mixed models(GLMMs)method yields the following conclusion:1)At the beginning of the breeding period,Gray-backed Shrike will determine the amount of breeding investment according to the surrounding environmental conditions.When environmental conditions are poor,Gray-backed Shrike will reduce reproductive input accordingly.2)Gray-backed Shrike adopts the asynchronous breeding strategy,and will reduce the level of competition among chicks by increasing the size of the eggs produced afterwards.3)Gray-backed Shrike brooding is mainly responsible for males,which indicates that there may not be responsible social behavior in Gray-backed Shrike.Both male and female parents expect the current nest breeding to succeed.4)The parenting behavior of Gray-backed Shrike is consistent with the predictions of both the quality signal model and the real signal model,which indicates that there may be more reproduction strategies in Gray-backed Shrike.5)The growth curve of Gray-backed Shrike nestlings shows that there has been a level difference in Gray-backed Shrike nestlings.Different birth order chicks have different status.6)The begging behavior of Gray-backed Shrike nestling will affect the feeding of the parental control in the parent-offspring conflict of Gray-backed Shrike.Parents control the degree of asynchronous hatching of nestling to reduce the intensity of competition between nestling.This study believes that in the process of Gray-backed Shrike parent-offspring conflicts,the Gray-backed Shrike parent-offspring conflict mode is mainly controlled by the Gray-backed Shrike parents.The reproduction strategy of Gray-backed Shrike breeding on the Tibet Plateau is greatly affected by the environment.It does not form a single evolutionary stable strategy,but multiple strategies coexist.Gray-backed Shrike will choose the corresponding strategy according to the change of environmental conditions.