文獻來源: Whilea GM, Ullerb T, Wapstraa E. 2009. Family conflict and the evolution of sociality in reptiles. Behavioral Ecology 2009 20(2):245-250; doi:10.1093/beheco/arp015俗稱刺尾岩蜥(對, 就是那個貴翻天的刺尾岩蜥)的Egernia屬石龍子在爬蟲學研究中是一個非常重要的類群, 因為牠們展現了極為複雜的社會性行為. 在此所談的社會性(sociality)並非如人類社會的角色分工, 而是廣義的, 在社會生物學中所關注的, 在形成真社會性(eusocial)生物前所可能經歷的行為演化歷程. 生物的社會化過程中被預測一定要發生的現象, 除了非生殖方面的性別分工, 或同一性別內的角色分工(如職蟻, 兵蟻)之外, 小家庭與一夫一妻制的形成都被認為是獨居生物步入社會型生物演化的里程碑之一, 然而小家庭與一夫一妻制的形成, 在演化上事實上有著許多利幣得失, 這篇文章便是藉著對懷特氏刺尾石龍子(E. whitii)的研究提出一些觀點. Egernia屬石龍子是蜥蜴中少數具有親代照護行為的類群, 而他們的小家庭通常由一對終生奉行一夫一妻制的父母與其北鼻所構成. 由於一個家庭的領土通常由雌性所踞守, 因此雌性便無法進行多次的配對(multiple mating), 而且出現在領土內的非婚生北鼻就會被爸爸所趕走甚至被咬死. 這樣更會增加媽媽與北鼻在一個家庭內的利益衝突. 這篇文章的主旨便在於探討天擇力量如何促進親代照護的穩定, 遺傳層面的配對忠誠度, 以及這些因素對於促進生物社會化以及社會化的龐雜度.
Mating systems and parental care are predicted to coevolve because the former dictates the cost–benefit ratio of the latter by affecting genetic relatedness between adults and offspring. Reptiles show only rudimentary forms of sociality and parental care and, hence, could provide important insights into the early stages of the evolution and maintenance of social systems. The skink genus Egernia exhibits the most complex form of sociality and parental care in lizards, with the formation of stable social groups typically consisting of a monogamous pair and their offspring. Here we show that, within a social group, offspring sired by males other than the social father are restricted to the area of the parental home range that is occupied exclusively by the mother. Thus, males rarely tolerate offspring within their home range that they are not genetically related to. This may increase the cost of multiple mating for females and offspring via increased risk of infanticide, reduced parental tolerance, and increased mother–offspring competition. We outline a verbal model for how this could generate a feedback loop in which selection favors reduced multiple mating by females and increased paternal care, thereby setting the stage for the evolution of complex sociality and genetic monogamy.
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