不同生活史阶段长爪沙鼠成体与亚成体间社会行为模式及其性别差异

Social behavior patterns and sex differences between adult and sub-adult Meriones unduiculatus at different life-history stages

【目的】对生活于高纬度地区的群居性小型哺乳动物而言,社会交往模式的季节变化有利于提高其适合度,是动物生活史对策的重要组份。长爪沙鼠(Meriones unguiculatus)是分布于荒漠草原和典型草原地区的优势鼠种之一,营集群生活,年生活史周期(即繁殖期和繁殖休止-贮食期)鲜明。然而,长爪沙鼠如何调整社会行为以响应生态背景变化,并对动物的繁殖、贮食以及越冬存活产生影响仍不清楚。【方法】于2001年,采用标志重捕对半自然长爪沙鼠种群进行了监测,同期对不同家群的成年-亚成年鼠组对,通过中立竞技场测定了成年雄-亚成雄、成年雄-亚成雌、成年雌-亚成雄以及成年雌-亚成雌4类组对个体间的社会行为,旨在检验如下假设:在应对不同生活史阶段的生态背景变化时,长爪沙鼠成年与未成年个体间的行为对策将显示适应性调整;且基于Bateman’s原则关于动物两性成功繁殖的资源限制差异,相关行为对策会显示性别差异。【结果】在繁殖期,成年鼠对同性亚成鼠的社会容忍(攻击性高,友好性低)较对异性亚成鼠低很多,其中,成年雄鼠对亚成年雄鼠的容忍性远远低于其他组合。而在繁殖休止-贮食期间,各类个体相遇时,尽管争斗和友好行为表现基本相似,但是在社会探究表现上,成年雌鼠较成年雄鼠明显花费更短的时间来嗅闻亚成体。同时,经不同季节比较发现,仅雄-雄间的争斗行为在繁殖休止时较繁殖期间有显著降低,其他个体间的争斗和友好行为变化并不明显;此外,成年雄对亚成年雌社会探究在贮食期较繁殖期明显增加。【结论】长爪沙鼠个体间的社会容忍性有其明显的性别和年生活史差异,反映了其在社会竞争生态过程中的行为适应对策。

【Objective】For small social mammals living in high latitudes,seasonal changes in social interaction patterns are beneficial to improve animal fitness and are an important component of animal life history strategies.Mer-iones unguiculatus are a social rodent that live in family group year-around,whose annual life-history includes 2 dis-tinct stages,i.e.breeding season(hereafter BP,March-August)and breeding-lull-food-hoarding season(hereafter NBP,September-October).However,little information is available about how gerbils modify their social behavior to respond to the changes in ecological context,which influences the benefits and costs of their interactions.【Method】In this study,we used neutral arena to test social interactions between adult and sub-adult Mongolian gerbils from differ-ent social groups under semi-natural conditions using monthly live trapping in south-central Inner Mongolia in 2001.The study was carried out in order to test the hypothesis that the behavioral strategies between adult and sub-adult gerbils would show adaptive adjustment to cope with the changes of the different ecological context in annual life his-tory stages,and these strategies varied with sex due to Bateman’s principles.The principle showed that the different resource constraints determined the reproductive success of males and females.【Result】The experiments showed that adult gebils′social tolerance(high agonistic and low amicable)to same-sex sub-adults was much lower than that to heterosexual sub-adults in BP,hereinto,encounters between adult males and sub-adult males were more agonistic and fewer amicable than other adult-subadult pairings.In contrast,during NBP,adult female mice spent significantly less time sniffing subadults than adult male mice in social inquiry,although the agonistic and amicable behaviors were basically similar.Moreover,the aggression of adult male-subadult male was encountered during BP higher than that in NBP,and the investigation of adult males to subadult males significantly increased during NBP than that in BP.Whereas,there was no significant life-history difference in the other encounters among them.【Conclusion】The re-sults were consistent with our hypotheses and revealed differential behavioral strategies to cope with selective pres-sures at different life-history stages between males and females of small mammals in high latitudes.