Lu Hong-Liang, Gao Jian-Fang, Guo Kun, Ji Xiang
Hangzhou Key Laboratory for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, Zhejiang, China.
Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, Zhejiang, China.
Curr Zool. 2022 Apr 27;69(3):277-283. doi: 10.1093/cz/zoac033. eCollection 2023 Jun.
We used , a sexually size-monomorphic lacertid lizard, as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized at a similar body size for both sexes. We allowed lizards housed in laboratory enclosures to lay as many clutches (for females) as they could or to mate as many times (for males) as they could in a breeding season. Size-assortative mating was weak but evident in , as revealed by the fact that male and female snout-vent lengths (SVLs) in mating pairs were significantly and positively correlated. Mating frequency (indicative of male reproductive performance) varied from 1 to 8 per breeding season, generally increasing as SVL increased in adult males smaller than 67.4 mm SVL. Clutch frequency varied from 1 to 7 per breeding season, with female reproductive performance (determined by clutch frequency, annual fecundity, and annual reproductive output) maximized in females with a SVL of 68.0 mm. Accordingly to our hypothesis, the reproductive performance was maximized in the intermediate sized rather than the largest individuals in both sexes, and the body size maximizing reproductive performance was similar for both sexes. Future work could usefully investigate other lineages of lizards with sexually monomorphic species in a phylogenetic context to corroborate the hypothesis of this study.
我们使用一种两性体型单态的蜥蜴作为模型系统，来检验这样一个假说：在两性生殖性能在相似体型下达到最大化的蜥蜴中，两性体型单态可能会进化。我们让饲养在实验室围栏中的蜥蜴在一个繁殖季节里尽可能多地产卵（对于雌性）或尽可能多地交配（对于雄性）。体型相配的交配行为较弱但在该蜥蜴中明显存在，这一点从交配配对中雄性和雌性的吻肛长度（SVL）显著正相关这一事实可以看出。交配频率（表明雄性生殖性能）在每个繁殖季节从1到8不等，对于成年雄性中SVL小于67.4毫米的个体，通常随着SVL的增加而增加。产卵频率在每个繁殖季节从1到7不等，雌性生殖性能（由产卵频率、年繁殖力和年生殖产出决定）在SVL为68.0毫米的雌性中达到最大化。根据我们的假说，两性中生殖性能在中等体型而非最大体型的个体中达到最大化，并且使生殖性能最大化的体型在两性中相似。未来的工作可以在系统发育背景下对具有两性体型单态物种的其他蜥蜴谱系进行有益的研究，以证实本研究的假说。
