NSF Postdoctoral Fellowship in Biology FY 2020: Exploring the genetic and behavioral basis of variation in sequestration ability in the polymorphic tortoise beetle

这一行动资助了2020财年NSF生物学博士后研究奖学金，扩大了生物学领域代表性不足群体的参与。该奖学金支持一项针对该研究员的研究和培训计划，该计划将增加生物学中代表性不足的群体的参与。这项研究的重点是一种在热带雨林中发现的五颜六色的龟甲，称为互花米草。这种甲虫的颜色在整个范围内都不同，它将寄主植物产生的毒素结合到外骨骼中，作为抵御捕食者的一种防御机制。通过加入有毒化合物，这些有机体变得令捕食者反感，并通过使用鲜艳和对比鲜明的颜色来宣传它们是有毒的，使捕食者更容易学习和记住避开它们。颜色或图案的变化往往预示着不同毒性水平的个体。这项研究试图了解个体在吸收植物毒素的能力上的差异如何有助于甲虫幼虫的存活和成年后的捕食。了解一些个体如何更好地处理毒素，将有助于深入了解昆虫适应环境和农业杀虫剂的方式。为了扩大参与，孟菲斯地区积极的高中生和本科生将接受研究方面的指导，并促进大学和社区之间的外展伙伴关系。为了了解种内变异如何调节多态甲虫幼虫对植物次生代谢物的封存能力，将进行一项综合研究，评估基因表达、幼虫和成虫适应能力以及功能基因组学的差异。在无菌生物中，颜色模式的变化通常表明个体具有不同程度的毒物保护。为了研究基因和表型对幼虫存活的影响，将对不同基因类型的个体进行幼虫存活的评估。捕食者与蚂蚁捕食者Azteca chartifex的生物测试将评估基因和表型对成虫适口性的影响。更善于处理植物次生代谢产物的个体在幼虫发育过程中预计会有更高的存活率，而那些更善于吸收这些代谢产物的个体在成年后预计会有更高的毒性和更少的捕食经历。表皮层碳氢化合物研究将被用来分析基因和表型之间的化学差异。此外，为了评估幼虫封存能力的变化，将确定与封存代谢途径相关的基因的表达模式。将化学生态学、基因组学和行为学结合起来，将有助于更深入地了解对幼虫存活、成虫化学特征和整体适口性水平的级联影响。为了扩大这项工作的影响，学生将接受研究方面的指导，并将进行社区推广。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Broadening Participation of Groups Under-represented in Biology. The fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. The focus of this study is a colorful tortoise beetle found in tropical rainforests, called Chelymorpha alternans. This beetle varies in color across its range and incorporates toxins produced by host plants into the outer exoskeleton as a defense mechanism against predators. By incorporating toxic compounds, these organisms become distasteful to predators, and by using bright and contrasting coloration they advertise that they are toxic, making it easier for predators to learn and remember to avoid them. Often variation in color or pattern signals individuals who differ in their level of toxicity. This research seeks to understand how individual differences in the ability to incorporate toxins from the plants contributes to survival in beetle larvae and predation as adults. Understanding how some individuals are better equipped to process toxins will provide insights into the ways that insects adapt to their environment and to agricultural pesticides. To broaden participation, motivated high school and undergraduate students in the Memphis area will be mentored in research and outreach partnerships between the University and the community will be facilitated.In order to understand how intraspecific variation mediates the sequestration ability of plant secondary metabolites by larvae of the polymorphic tortoise beetle, C. alternans, an integrative study assessing differences in gene expression, larval and adult fitness and functional genomics will be performed. In aposematic organisms, variation in color pattern often indicates individuals with differing levels of toxic protection. To investigate the genotypic and phenotypic impacts on larval survival, individuals of different genotypes will be assessed for larval survival. Predator bioassays with the ant predator, Azteca chartifex, will be conducted to assess genotypic and phenotypic impacts on adult palatability. Individuals that are better at processing secondary metabolites from the plant are expected to have higher survival through larval development, and those that are better at incorporating these metabolites are expected to have increased toxicity and experience less predation as adults. A cuticular hydrocarbon study will be used to analyze chemical variation between genotypes and phenotypes. Additionally, to assess variation in larval sequestration ability, the expression patterns of genes related to sequestration metabolic pathways will be determined. Combining chemical ecology, genomics and behavior will facilitate deeper insights in cascading effects on larval survival, adult chemical profiles and overall levels of palatability. To broaden the impact of the work, students will be mentored in research and community outreach will be conducted.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.