DISSERTATION RESEARCH: The effects of sexual dimorphism on morphological diversification of Musteloidea

论文研究：两性二态性对鼬总科形态多样性的影响

• 批准号: 1700989
• 负责人: Rita Mehta
• 金额: $ 1.92万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1700989&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; effects; sexual; dimorphism

Uneven diversity in both numbers of species and anatomical variability represents one of the more perplexing evolutionary patterns across the Tree of Life. Although an increasing number of researchers have begun to understand what drives uneven diversity between species, few researchers have examined how differences within single species can affect these broad scale evolutionary patterns. One source of variation lies in the difference between the sexes. The primary goal of this research is to build upon evolutionary theory by examining how sex differences contribute to species and phenotypic diversity. This research fills a critical gap in our understanding of how variation within species may drive larger patterns of species diversity. Through this research program, scientists will contribute to training the next generation of students through their mentorship of high school students through the UC Santa Cruz Science Internship Program (SIP), undergraduate student training in the Small Mammal Undergraduate Research in the Forest (SMURF) program, public talks through the Santa Cruz Public Library, and undergraduate teaching in Comparative Vertebrate Anatomy. The skulls of musteloids (badgers, otters, raccoons, skunks, and weasels) will be used as a model to examine the effects of sexual dimorphism on phenotypic disparity at the macroevolutionary scale. Musteloids are a taxonomically rich and phenotypically disparate clade whose lineages exhibit uneven patterns of diversity. The researchers will use 3D geometric morphometrics and develop new comparative methods to test the hypothesis [H1a] that incorporating the effects of sex will reveal increased cranial disparity. Males and females in each species are predicted to occupy mostly non-overlapping parts of cranial morphospace; furthermore, the inclusion of both sexes will fill morphospace that was previously unoccupied when the analysis focused on a single sex. The researchers will then quantify the rates of cranial disparity through time in males and females separately and pooled together (species means) to test the hypothesis [H1b] that incorporating sex enhances the pattern of adaptive radiation (i.e. rapid increases in evolutionary rates near ecological opportunity followed by a slowdown in rates). A rate shift in cranial evolution is predicted to occur just after the onset of the Mid-Miocene Climate Transition when using the pooled male and female dataset. Lastly, the researchers will examine an ecological basis for sexual dimorphism by testing the hypothesis [H2] that the degree of carnivory corresponds with the evolution of sexual dimorphism in cranial shape and size across Musteloidea. Therefore, hypercarnivorous musteloids are predicted to exhibit the highest degree of cranial sexual dimorphism. We suspect that this disparity in hypercarnivores is present to mitigate competition between the sexes.

物种数量和解剖变异性的不均匀多样性代表了生命之树中更令人困惑的进化模式之一。尽管越来越多的研究人员已经开始了解是什么导致了物种之间多样性的不均匀，但很少有研究人员研究过单个物种内的差异如何影响这些广泛的进化模式。差异的来源之一在于性别之间的差异。这项研究的主要目标是通过研究性别差异如何影响物种和表型多样性来建立进化论。这项研究填补了我们对物种内变异如何驱动更大的物种多样性模式的理解的一个关键空白。通过这项研究计划，科学家们将通过加州大学圣克鲁斯分校科学实习计划 (SIP) 指导高中生、森林小哺乳动物本科生研究 (SMURF) 计划的本科生培训、通过圣克鲁斯公共图书馆的公开演讲以及比较脊椎动物解剖学的本科教学，为培养下一代学生做出贡献。鼬科动物（獾、水獭、浣熊、臭鼬和黄鼠狼）的头骨将被用作模型，以在宏观进化尺度上研究性二态性对表型差异的影响。鼬类是一个分类丰富且表型不同的分支，其谱系表现出不均匀的多样性模式。研究人员将使用 3D 几何形态测量学并开发新的比较方法来检验假设 [H1a]，即结合性别的影响将揭示颅骨差异的增加。预计每个物种的雄性和雌性将占据颅骨形态空间的大部分非重叠部分；此外，包含两种性别将填补以前在分析集中于单一性别时未占据的形态空间。然后，研究人员将分别量化男性和女性随时间变化的颅骨差异率，并将其汇总在一起（物种平均值），以检验假设[H1b]，即性别的结合增强了适应性辐射的模式（即，在接近生态机会时，进化率迅速增加，随后速度减慢）。当使用汇集的男性和女性数据集时，预计中中新世气候转变开始后，颅骨进化的速率会发生变化。最后，研究人员将通过检验假设[H2]来研究两性二态性的生态基础，即食肉性的程度与鼬总科颅骨形状和大小的两性二态性的进化相对应。因此，预计超肉食性鼬科动物会表现出最高程度的颅骨两性二态性。我们怀疑超级食肉动物的这种差异是为了减轻性别之间的竞争。

项目成果

Evolutionary shifts in extant mustelid (Mustelidae: Carnivora) cranial shape, body size and body shape coincide with the Mid-Miocene Climate Transition

• DOI: 10.1098/rsbl.2019.0155
• 发表时间: 2019-05
• 期刊: Biology Letters
• 影响因子: 3.3
• 作者: Chris J. Law

Carnivory maintains cranial dimorphism between males and females: Evidence for niche divergence in extant Musteloidea

食肉动物维持雄性和雌性之间的颅骨二态性：现存鼬总科生态位差异的证据

• DOI: 10.1111/evo.13514
• 发表时间: 2018
• 期刊: Evolution
• 影响因子: 3.3
• 作者: Law, Chris J.;Mehta, Rita S.
• 通讯作者: Mehta, Rita S.

Effects of diet on cranial morphology and biting ability in musteloid mammals

饮食对鼬类哺乳动物颅骨形态和咬合能力的影响

• DOI: 10.1111/jeb.13385
• 发表时间: 2018
• 期刊: Journal of Evolutionary Biology
• 影响因子: 2.1
• 作者: Law, Chris J.;Duran, Emma;Hung, Nancy;Richards, Ekai;Santillan, Isaac;Mehta, Rita S.
• 通讯作者: Mehta, Rita S.

Shared extremes by ectotherms and endotherms: Body elongation in mustelids is associated with small size and reduced limbs

变温动物和恒温动物的共同极端：鼬科动物的身体伸长与体型小和四肢减少有关

• DOI: 10.1111/evo.13702
• 发表时间: 2019
• 期刊: Evolution
• 影响因子: 3.3
• 作者: Law, Chris J.;Slater, Graham J.;Mehta, Rita S.
• 通讯作者: Mehta, Rita S.