DISSERTATION RESEARCH: Does Hormone Provisioning Link Maternal Social Environment and Offspring Phenotype?

在动物中，当一个人的身体和行为与环境相匹配时，成功就会最大化。动物通常依靠类固醇激素来适应它们所处的环境。但是在年轻个体中，发育过程中激素浓度的微小差异可以深刻地改变后来的生存和行为。在发育过程中，母亲的激素水平影响着她正在发育的后代，因此不仅影响着她自己的直接生存，也影响着她所生的孩子的生存。许多研究已经验证了这样一种观点，即母亲提供给后代的类固醇激素可以帮助后代利用成年后的环境。然而，这些研究使用的是在出生后照顾后代的动物。母亲是否可以单独使用类固醇激素来优化后代，或者养育行为也是必要的？这个项目将通过测量一种类固醇激素对后代发育和存活的影响来研究这个问题，这种昆虫的后代不需要父母的照顾。研究结果将表明，母亲是否可以在不依赖父母照顾的情况下，使用类固醇激素为后代未来的行为环境做好准备。因为无论物种如何，每个母亲都会将激素传递给她的后代，这项研究的结果将扩大我们对激素如何跨代发挥作用的总体理解。因此，它可能与濒危物种和环境的保护以及个性化医疗特别相关。这种广泛的适用性也将促进与当地K-12学生的联系，研究结果将通过出版物和演讲向科学界展示。这项研究将调查一种无脊椎动物（Acheta domesticus，即家蟋蟀）的母性影响和攻击行为，这种动物不照顾后代，但自然地经历了可变的社会环境。先前的数据表明，卵子中较高水平的表皮甾体激素（ESH）与幼雏的适应性增加有关。拟议的研究解决了这样一个问题，即父母是否以及在多大程度上没有与后代接触，可以改变后代的发育和行为表型，以应对社会环境，并仅通过母体的内分泌影响。雌性蟋蟀将在四种社会环境（高、低总密度、高雌密度和高雄密度）中饲养，并测量其卵的ESH沉积和总繁殖量。本文提出的研究将通过在没有亲代照顾的系统中测量激素供应来解开母亲激素供应和亲代照顾对后代生活史的影响。这项工作还将提供更多关于蜕皮激素（ESH）的生态和进化功能的信息，迄今为止，蜕皮激素主要是在胚胎发生和蜕皮的背景下研究的，并且通常被低估为长期“组织”效应的介质。最后，本研究通过考虑独立进化的昆虫内分泌系统的假设，对目前使用脊椎动物研究系统建立的行为内分泌学框架进行了验证。

In animals, when ones' body and behavior are matched to the environment success is maximized. Animals often rely on steroid hormones to adapt to the environments they are in. But in young individuals small differences in the concentration of hormones during development can profoundly alter later survival and behavior. During development a mother's hormone levels impact her developing offspring, and therefore impact more than her own immediate survival but also that of the young she produces. Many studies have tested the idea that steroid hormones provided by mothers to their offspring could help offspring exploit their later adult environment. However, these studies have used animals that take care of their offspring after birth. Can mothers use steroid hormones alone to optimize offspring, or is parenting behavior also necessary? This project will investigate that question by measuring the effects of a steroid hormone on offspring development and survival in an insect species that provides no parental care to its offspring. The results will show whether mothers can use steroid hormones to prime their offspring for future behavioral environments without relying on parental care. Because every mother transmits hormones to her offspring regardless of species, the results of this study will amplify our general understanding of how hormones function across generations. As such, it will likely be especially relevant to conservation of endangered species and environments, and individualized medicine. This broad applicability will also facilitate outreach to local K-12 students and findings will be presented to the scientific community through publications and presentations. This study will investigate maternal effects and aggressive behavior in an invertebrate (Acheta domesticus, the house cricket) that provides no care to offspring, but which naturally experiences variable social environments. Previous data shows that higher levels of ecdysteroid hormones (ESH) in eggs are associated with increased fitness for hatchlings. Proposed research addresses the question of whether and to what extent parents that have no later contact with their offspring can alter the development and behavioral phenotype of said offspring in response to social environment and through endocrine maternal effects alone. Female house crickets will be raised in four social environments (high and low total density, high female density and high male density), and their egg ESH deposition and total reproductive output will be measured, also. Research proposed here will disentangle the effects of maternal hormone provisioning and parental care on offspring life history by measuring hormone provisioning in a system without parental care. This work will also provide more information about ecological and evolutionary functions of ecdysteroid hormones (ESH), which have until now been studied primarily in the context of embryogenesis and molting and are generally underappreciated as mediators of long-term 'organizational' effects. Finally, this research tests the current behavioral endocrinology framework established using vertebrate study systems by considering hypotheses in the independently evolved insect endocrine system.