Parentage Testing And Family Groups Determination Of Chinese White-Bellied Rats(Niviventer Confucianus) In Thousnad Island Lake

Parentage testing of wild animal populations may reflect mating relationship and system between animals in a natural environment, and may reveal the mechanism of natural populations to adapt to the complex and flexible environmental conditions. Microsatellite molecular markers combined with macro-monitoring methods provide a new way to paternity testing wild natural populations. In this study, we tested parentage of Chinese white-bellied rats (Niviventer confucianus) that were mark-recaptured from September2009to August2010in two islands of Thousand Island Lake with8specific highly polymorphic microsatellite loci. Parentage and family group of the2islands Niviventer confucianus populations were analyzed as well as the mating system was preliminarily detected to explore the characteristics of relatedness of Niviventer confucianus family groups. The main results and conclusions are as follows:1. Eight microsatellite loci can reliably analyze parentage of Chinese white-bellied populations of the2islands. Kinship of71and49individuals respectively in island A and B were identified, and determined rate were both more than50%. The reproductive status reflected by parentage of the2populations was consistent with previous studies. Results suggested that mating system of Chinese white-bellied rat was promiscuity, and inbreeding was existed in both islands. This may imply that condition of resource-constrained in closed island may intensify mate competition, and promiscuity may help enhance the reproductive success in closed island.2.71individuals of A island that had identified kinships were divided into12family groups, which the number of members in family groups was up to19. And49individuals of B island that had identified kinships were divided into11family groups, which the number of members in family groups was up to14. The relatedness of male-female pairs for reproduction (M-F pair) was lowest compared with other pairwises, which may reveal that Chinese white-bellied rats avoid choosing closer related individuals as mates. However, the presence of inbreeding may be associated with the complex environment of the island. Relatedness of male-male (M-M) and female-female (F-F) in offspring individuals showed inconsistent performances between A island and B island, which may inferred some different particularity of dispersal in2islands. Relatedness of the individual pairwises that mate with the same male or female slightly inferred some information of mate choices. I predicted that Chinese white-bellied rat prefers to avoid choosing different individuals which have close relatedness as different mates. The mating system, family group and dispersal of Chinese white-bellied rat need further and deeply study.3. The home range overlap of members in family groups of2islands showed inconsistent results. Home range overlap of pair breeding individuals in island A was more common than that in island B. And there was inconsistence in2islands between the overlap of parent pairs and the overlap of offspring pairs. This might reflect that females would have nursery behaviors and males would increase the overlap with females for obtaining more mating opportunities. The overlap of offspring pairs might performance some association with their relatedness. And the full siblings that had closer relationship than half siblings might be more likely to share spatial resources. The association between overlap and relatedness of individuals in family groups probably implied the competition of mates and resources. Studies on characteristic of home range overlap and family groups that responses to flexible and variable environment conditions need to do deeply.