DISSERTATION RESEARCH: Evolution of Sexual Dichromatism in Butterfly Wing Coloration: Evaluating the Importance of Nitrogen Limitation and Sexual Signaling

鲜艳的颜色是动物界最令人着迷但却鲜为人知的特征之一。莫尔豪斯和鲁托斯基将调查在蝴蝶身上发现的由蝶类色素产生的颜色。在菜青蝶(Pieris Rapae)中，雄性蝴蝶比雌性蝴蝶在翅膀上沉积更多的蝶类激素，这导致雄性蝴蝶比其他蝴蝶拥有更五颜六色的外表。有趣的是，这些蝶类色素富含氮，这是这些蝴蝶在幼虫发育过程中无法获得的一种元素。这表明，这些色素的生产成本可能很高，特别是考虑到雄鸟在翅膀中沉积的数量。那么，为什么雄性会投资于这些翅膀的颜色呢？也许雄性用它们鲜艳的翅膀颜色来宣传自己作为潜在配偶的质量，要么是为了证明他们在生命早期就以特别丰富的饮食为食，要么是为了表明他们从饮食中提取氮的效率更高。莫尔豪斯和鲁托斯基将研究基因和幼虫饮食如何影响这些蝴蝶的翅膀颜色，以更好地理解这些明亮的颜色所编码的信息。他们还将评估雌性蝴蝶对翅膀颜色不同的雄性蝴蝶的反应，以更好地了解雌性蝴蝶是否根据雄性颜色在潜在配偶中进行选择。这些研究的结果不仅将解释为什么这些蝴蝶的颜色鲜艳，而且还将揭示这些动物如何在有限的营养资源上平衡各种需求。除了这些预期的成就之外，这项研究还将提供绝佳的机会，从代表性不足的群体中招募学生进入科学领域的职业道路。莫尔豪斯和鲁托斯基将继续指导来自不同背景和种族的本科生研究人员，并在当地课堂、社区组织和科学会议上向公众传播他们对五颜六色的动物的迷恋。

Bright colors are some of the most fascinating and poorly understood traits in the animal kingdom. Morehouse and Rutowski will investigate colors found in butterflies that are produced by pterin pigments. In the Cabbage White butterfly (Pieris rapae), male butterflies deposit more pterins in their wings than do females, which results in the males having a more colorful appearance to other butterflies. Intriguingly, these pterin pigments are rich in nitrogen, an element which these butterflies have limited access to during larval development. This suggests that these pigments might be costly to produce, especially given the amounts that males deposit in their wings. Why then do males invest in these wing colors? Perhaps males use their bright wing colors to advertise their quality as potential mates, either as a demonstration that they fed on a particularly rich diet early in life, or as an indication that they are more efficient at extracting nitrogen from their diet. Morehouse and Rutowski will examine how genes and larval diet affect the wing colors of these butterflies to better understand the information these bright colors encode. They will also evaluate the response of female butterflies to males with varying wing colors to better understand whether females choose among potential mates on the basis of male coloration. The results of these studies will not only illuminate why these butterflies are brightly colored, but will also reveal how these animals juggle the various demands on their limited nutrient resources. In addition to these anticipated accomplishments, this research will provide outstanding opportunities to recruit students from underrepresented groups into career paths in science. Morehouse and Rutowski will continue to mentor undergraduate researchers from a diversity of backgrounds and ethnicities, and communicate their fascination with colorful animals to public audiences in local classrooms, community organizations and scientific meetings.