Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire, OX13 5QL, UK.
Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire, OX13 5QL, UK.
Zoology (Jena). 2019 Aug;135:125688. doi: 10.1016/j.zool.2019.04.005. Epub 2019 May 18.
Sexual size dimorphism (SSD) is common among mammals, with males typically being larger than females, as a product of sex-specific differences in growth rate and growth duration. The Musteloidea, however, exhibit a hypo-allometric reduction in SSD with increasing body size (contrary to Rensch's rule). A variety of extrinsic factors can affect juvenile growth rates and end body size, where one sex may demonstrate greater vulnerability than the other towards a specific factor, moderating patterns and degrees of SSD. Here, we analyse how male and female European badgers (Meles meles) differ in their somatic growth patterns. We compare the sex-specific growth curves across a range of somatic parameters and investigate what extrinsic (social and environmental) factors affect cub growth rates during the first 2 years of life leading to their sexual-dimorphic adult sizes. We found that average male final size of all measurements was significantly larger than those of females. Although male and female weanling cubs had similar body sizes, growth curves diverged significantly from ca. 11 months onwards due to continuous rapid growth of males versus slowing female growth. Consequently, females always concluded growth earlier than did males. In both sexes, extremities ceased to grow at an earlier age than did body length and zygomatic arch width. All badger cubs were impacted by their social environment as well as by weather conditions; however, male cubs were more sensitive to social factors, remaining smaller in social groups with more adult males present, whereas female final size was predominantly affected by weather and associated food availability. We discuss how extrinsic parameters can moderate patterns of SSD in the context of the differential equilibrium model.
性二型大小差异（SSD）在哺乳动物中很常见，雄性通常比雌性大，这是由于生长速度和生长持续时间的性别特异性差异所致。然而，鼬科动物的 SSD 随着体型的增大呈反伦希氏法则的低比例缩小。各种外在因素会影响幼体的生长速度和最终体型，其中一种性别可能比另一种性别对特定因素更为脆弱，从而调节 SSD 的模式和程度。在这里，我们分析了欧洲獾（Meles meles）雄性和雌性在身体生长模式上的差异。我们比较了一系列身体参数的性别特异性生长曲线，并研究了哪些外在（社会和环境）因素会影响幼崽在生命的头 2 年的生长速度，从而导致其具有性二型的成年体型。我们发现，所有测量值的雄性平均最终体型明显大于雌性。尽管雄性和雌性的断奶幼崽体型相似，但从大约 11 个月开始，由于雄性持续快速生长而雌性生长放缓，生长曲线明显出现分歧。因此，雌性总是比雄性更早结束生长。在两性中，四肢停止生长的年龄早于体长和颧骨宽度。所有獾幼崽都受到其社会环境和天气条件的影响；然而，雄性幼崽对社会因素更为敏感，在成年雄性较多的社会群体中体型较小，而雌性的最终体型主要受天气和相关食物供应的影响。我们讨论了外在参数如何在差异平衡模型的背景下调节 SSD 的模式。
