Dissertation Research: Adaptive behavioral and physiological changes among populations undergoing range expansion

非本地物种在其引入的范围内造成重大的生态和经济破坏;重要的是要确定入侵的预测因子，以防止未来的入侵。这一信息在评估本地物种对环境变化的脆弱性方面可能也很重要。 最近的引进事件之一，家麻雀（Passer arteriticus）到肯尼亚，仍在扩大超过最初引进的网站。肯尼亚家雀没有很高的遗传多样性，但仍然表现出广泛的行为和生理变化;有趣的是，观察到的变化与人口的估计年龄相关。 最接近范围边缘的家雀更具探索性，并释放更多的应激激素（糖皮质激素），以应对压力，而不是那些更接近最初引入的网站。 然而，这些性状差异在适应性沿着范围扩展方面意味着什么是未知的;此外，由于缺乏遗传多样性，这些差异是如何产生的也是未知的。 本研究的目的是确定A）增加探索和应激激素是否在范围边缘赋予适应性优势，但在更熟悉的栖息地中是不利的;以及B）这些差异是否是由于后代发育过程中母亲照顾的差异而产生的。 为了验证这些问题，将在肯尼亚进行自然父母照顾的观察以及在巢箱殖民地的雏鸟期间对母亲提供能力的操纵。PI预测，增加探索和应激激素会增加范围边缘的适应性，但会降低引入的适应性。 此外，还预计，食物补充将产生后代最像那些自然发生在现场的引进和减少供应将产生后代类似的范围边缘。 拟议的研究将加强国际合作，并为代表性不足的少数STEM本科生提供研究机会。

Non-native species cause major ecological and economic damage in their introduced range; it is important to identify predictors of invasiveness to prevent future invasions. This information might also prove to be important is assessing the vulnerability of native species to environmental change. One of the most recent introduction events, the house sparrow (Passer domesticus) to Kenya, is still expanding beyond the site of initial introduction. Kenyan house sparrows do not have high genetic diversity, however still exhibit extensive behavioral and physiological variation; interestingly, the observed variation is correlated with the estimated age of the population. House sparrows closest to the edge of the range are more exploratory and release more stress hormones (glucocorticoids) in response to stressors than those closer to the site of initial introduction. However, what these trait differences mean in terms of fitness along the range expansion is unknown; further, how these differences arise given the lack of genetic diversity is also unknown. The goal of the present research is to determine A) if increased exploration and stress hormones grant a fitness advantage at the range edge, but a disadvantage in more familiar habitats; and B) whether these differences arise due to differences in maternal care during offspring development. To test these questions, observation of natural parental care as well as manipulattion of a mother's ability to provision during the nestling period in nestbox colonies will be carried out in Kenya. The PI predicts that increased exploration and stress hormones increase fitness at the edge of a range, but decrease it at the site of introduction. Further, it is also expected that food supplementation will generate offspring most like those naturally occurring at the site of introduction and a reduction of provisioning will produce offspring similar to those at the range edge. The proposed study will strengthen international collaborations and provide research opportunities for underrepresented minority STEM undergraduates.