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

在动物王国里，鲜艳的颜色是最迷人的，也是最不为人所知的特征。莫尔豪斯和鲁托斯基将研究在蝴蝶身上发现的由蝶呤色素产生的颜色。在卷心菜白蝴蝶（Pieris rapae）中，雄性蝴蝶比雌性蝴蝶在翅膀上沉积更多的斑蝶，这导致雄性蝴蝶的外表比其他蝴蝶更鲜艳。有趣的是，这些翼素色素富含氮元素，而这些蝴蝶在幼虫发育过程中很少接触到氮元素。这表明，这些色素的生产成本可能很高，尤其是考虑到雄性在翅膀上沉积的数量。那么，为什么雄性会选择这些翅膀的颜色呢？也许雄性用它们鲜艳的翅膀颜色来宣传自己作为潜在伴侣的品质，或者是为了证明它们在生命早期吃了特别丰富的食物，或者是为了表明它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的饮食如何影响这些蝴蝶翅膀的颜色，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不同翅膀颜色的雄性蝴蝶的反应，以更好地了解雌性蝴蝶是否会根据雄性蝴蝶的颜色来选择潜在的伴侣。这些研究的结果不仅将阐明为什么这些蝴蝶颜色鲜艳，而且还将揭示这些动物如何对有限的营养资源进行各种需求。除了这些预期的成就之外，这项研究还将为从代表性不足的群体中招募学生进入科学职业道路提供出色的机会。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，并在当地教室、社区组织和科学会议上向公众传达他们对彩色动物的迷恋。

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.