Fallback Food Seasonality and the Plasticity of Craniomandibular Development

灵长类动物的颅骨变异受咀嚼压力的影响，依赖于坚硬和/或坚韧食物的类群通常拥有更坚固的头骨，颌骨和颌骨肌肉。 大多数灵长类动物都有季节性饮食，只在一年中的一部分时间而不是连续地关注难以加工的“后备”食物。 事实上，后备食物的生态形态学意义正在成为灵长类生物学和进化中的关键突出问题之一。 不幸的是，这种抗性食物的季节性与年度加工可能会影响颅骨生长和形状的变化程度尚不清楚。 探索季节性的影响，在头骨发育的食物材料的属性是至关重要的古生物重建，以及了解适应性可塑性和表型变化的灵长类动物头骨和摄食器的生态基础。 因此，本研究测试的假设，即长期的频率升高的负载在断奶后个体发育的结果在较高的增长轨迹和较大的成年咀嚼比例。 重要的相似性存在于形态，行为，功能，个体发育和可塑性的喂养复合体之间的兔子和灵长类动物，这将有助于这种比较。 兔子兄弟姐妹在不同性质的饮食中长大，一组具有对照/正常饮食，一组吃“年度”抗腹泻饮食，一组受到饮食韧性和刚度的“季节性”增加，以模拟依赖后备食物的波动。 出生后的三个阶段正在接受检查，通过内部和外部解剖结构的3D成像评估颅骨变化。 在弥合差距之间的实验室和基于现场的可塑性和进化的研究，这项研究提供了一个新的和及时的评估的作用，饮食季节性对颅个体发育。 更广泛的影响将是为博士后，研究生和本科生学员，特别是代表性不足的群体和当地K-12社区提供跨学科培训。 对社会的好处包括收集必要的了解如何模仿肌肉骨骼组织的生长活动，并确定咀嚼参数进行检查，在现场标本的负荷引起的反应的数据。

Cranial variation in primates is influenced by masticatory stresses, with taxa relying on stiff and/or tough foods often possessing more robust skulls, jaws and jaw muscles. Most primates exhibit seasonal diets, focusing on difficult-to-process "fallback" foods only part of the year rather than continuously. Indeed, the ecomorphological significance of fallback foods is emerging as one of the key outstanding issues in primate biology and evolution. Unfortunately, the extent to which the seasonal vs. annual processing of such resistant foods might affect variation in cranial growth and form is unknown. Exploring the influence of seasonality in food material properties on skull development is vital for paleobiological reconstructions as well as for understanding the ecological bases of adaptive plasticity and phenotypic variation in the primate skull and feeding apparatus. Thus, this research tests the hypothesis that the long-term frequency of elevated loading during post-weaning ontogeny results in higher growth trajectories and larger adult masticatory proportions. Important similarities exist in the morphology, behavior, function, ontogeny and plasticity of the feeding complex between rabbits and primates that will facilitate such comparisons. Rabbit siblings are raised on diets of different properties, with one group having a control/normal diet, one eating an "annual" fracture-resistant diet, and one subjected to "seasonal" increases in dietary toughness and stiffness to model fluctuations in the reliance on fallback foods. Three postnatal stages are being examined, with cranial variation evaluated via 3D imaging of internal and external anatomy. In bridging the gap between lab- and field-based studies of plasticity and evolution, this research offers a novel and timely assessment of the role of dietary seasonality on cranial ontogeny. A broader impact will be to provide interdisciplinary training for postdoctoral, graduate and undergraduate trainees, especially under-represented groups and the local K-12 community. The benefit to society includes collecting data on load-induced responses necessary for understanding how to mimic the growth activity of musculo-skeletal tissues, and for identifying masticatory parameters to be examined in field specimens.