School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand.
Center for Biodiversity and Restoration Ecology, Victoria University of Wellington, Wellington 6012, New Zealand.
Biol Open. 2022 Oct 15;11(10). doi: 10.1242/bio.059393. Epub 2022 Oct 14.
The morphological characteristics that impact feeding ecology in ectotherms, particularly reptiles, are poorly understood. We used morphometric measures and stable isotope analysis (carbon-13 and nitrogen-15) to assess the link between diet and functional morphology in an island population of an evolutionarily unique reptile, the tuatara (Sphenodon punctatus). First, we established a significant positive correlation between overall body size, gape size, and fat store in tuatara (n=56). Next, we describe the relationship between stable isotope profiles created from whole blood and nail trim samples and demonstrate that nail trims offer a low-impact method of creating a long-term dietary profile in ectotherms. We used nitrogen-15 values to assess trophic level in the population and found that tuatara on Takapourewa forage across multiple trophic levels. Finally, we found a significant relationship between gape size and carbon-13 (linear regression: P<0.001), with tuatara with large gapes showing dietary profiles that suggest a higher intake of marine (seabird) prey. However, whether body size or gape size is the primary adaptive characteristic allowing for more optimal foraging is yet unknown. This article has an associated First Person interview with the first author of the paper.
形态特征对外温动物（尤其是爬行动物）的进食生态有影响，但人们对此知之甚少。我们使用形态计量学测量和稳定同位素分析（碳-13 和氮-15）来评估饮食与功能形态之间的联系，研究对象是一种进化独特的爬行动物——图阿托拉（Sphenodon punctatus）在一个岛屿种群中的情况。首先，我们确定了图阿托拉的整体体型、口裂大小和脂肪储存之间存在显著的正相关关系（n=56）。接下来，我们描述了从全血和指甲修剪样本中创建的稳定同位素图谱之间的关系，并证明指甲修剪是一种在爬行动物中创建长期饮食模式的低影响方法。我们使用氮-15 值来评估该种群的营养水平，发现图阿托拉在塔卡普雷瓦岛觅食跨越多个营养水平。最后，我们发现口裂大小和碳-13 之间存在显著关系（线性回归：P<0.001），口裂较大的图阿托拉的饮食模式表明它们摄入了更多的海洋（海鸟）猎物。然而，是体型还是口裂大小是允许更优化觅食的主要适应特征尚不清楚。本文附有该论文第一作者的相关第一人称采访。
