Collaborative Research: Development and Identity of Sexually Dimorphic Reproductive Signals and Responses by African Elephants

在BIO C-RUI项目的精神下，该提案跨越了学科、部门和机构的界限。该项目将利用生物学和化学界面的创新技术回答有关生殖交流的近似机制的五个问题。非洲象将被用来测试关于两性二态生殖信号和反应的发育模式的假设。这不仅是因为大象作为研究对象具有独特的优势，而且还因为基础科学研究可以提供有关这些具有重要生态意义的濒危动物的知识，这可能有助于它们的长期生存。这个研究小组包括一名动物行为学家（舒尔特博士）和一名有机化学家（古德温博士），他们都有在以本科生为主的院校进行过成功的大象相关研究的记录。Rasmussen博士对亚洲象的排卵期前信息素进行了描述，并对大象的生物化学、行为和嗅觉的理解做出了重大贡献，他加入了团队。这些科学合作者是教育工作者，他们认为本科生通过做科学来学习科学最好，即通过与科学家一起参与研究，在科学会议上展示结果，以及共同撰写手稿。本科合作者将积极参与两性二态生殖信号和反应的研究。一夫多妻制的动物通常表现出极端的两性二态性，雄性和雌性可能生活在非常不同的社会结构中。在哺乳动物中，雌性通常在很少或没有雄性帮助的情况下抚养后代。非洲象（Loxodonta africana）很好地说明了这一模式。两性间的互动在繁殖季节尤其普遍，因为个体使用各种交流行为来竞争和选择配偶以及维持社会关系。化学信号和相关的触觉行为是评估生殖状况和吸引配偶的主要手段。化学信号产生和性别特异性反应的发展很少受到关注。事实上，在一项研究中，很少同时比较同一物种中与生殖有关的两性二态通信模式。这些领域的焦点问题分为三组：第一组：排卵前尿液中有哪些特定的化学信号：A.引发男性生殖行为？引起女性社会反应的增强？第二集：在男性和女性的不同发育过程中，是否存在以下可识别的阶段：A.男性对排卵期前尿液及其特定化学信号的反应？B.女性对排卵期前尿液的反应及其特定化学信号？第三部分：基于前两部分的结果，男性和女性对已知化学信号源和特定信号化合物的反应，以及更普遍的生殖相关行为的表现，有什么比较的个体发生模式？这些问题首先通过研究女性到男性的信号（IA和IIA），然后是女性到女性的信号（IB和IIB），最后通过比较两种发育途径（III）来研究。具体来说，答案是通过以下方式寻求的：(i)收集圈养和野生雌性非洲象的尿液；对男性和女性同类的尿液样本进行行为生物分析；化学分析具有生物活性的尿液成分以确定有机化合物；用圈养非洲象和野生非洲象对选定的尿液成分进行生物测定；观察野生非洲象进行生殖化学接触交流。拟议的研究将确定生殖行为的近似化学原因，并阐明两性交流的二态发育模式。本研究将为进一步研究男性信号和解决这一主题的终极问题奠定基础。这一发现可能有助于保护濒临灭绝的大象和其他物种。

Collaborative Research: RUI - Development and Identity of Sexually DimorphicReproductive Signals and Responses by African ElephantsIn the spirit of the BIO C-RUI program, this proposal crosses disciplinary, departmental, and institutional boundaries. The project will answer five questions regarding the proximate mechanisms of reproductive communication using innovative techniques at the interface of biology and chemistry. African elephants will be used to test hypotheses on developmental patterns of sexually dimorphic reproductive signals and responses. This is not only for the distinct advantages elephants offer as a research model, but also because basic scientific research can provide knowledge about these ecologically important, endangered animals that may aid in their long-term survival. This research team includes an animal behaviorist (Dr. Schulte) and an organic chemist (Dr. Goodwin), each with a track record of successful elephant-related research at predominantly undergraduate institutions. Dr. Rasmussen, who characterized the pre-ovulatory pheromone in Asian elephants and has made substantial contributions to the understanding of elephant biochemistry, behavior and olfaction, joins the team. These scientific collaborators are educators who believe that undergraduates learn science best by doing science, i.e. by research participation with scientists, presentation of results at scientific meetings, and co-authoring manuscripts. Undergraduate collaborators will actively participate in this research on sexually dimorphic reproductive signals and responses.Polygamous animals often display extreme sexual dimorphism, where males and females may live in very different social structures. In mammals, females typically raise the offspring often with little or no male assistance. African elephants (Loxodonta africana) illustrate this pattern very well. Intersexual interaction is especially prevalent during the breeding season when individuals use a variety of communicative behaviors to compete for and select mates as well as maintain social bonds. Chemical signals and related tactile behaviors are primary means of evaluating reproductive condition and attracting mates. The development of chemical signal production and sex-specific responses has received little attention. In fact, sexually dimorphic communication patterns related to reproduction have rarely been compared within the same species simultaneously in a single study. Focal questions in these arenas are posed in three sets:SET I: What are the specific chemical signals in pre-ovulatory urine that: A. Elicit male reproductive behavior? B. Elicit heightened female social responsiveness?SET II: During the differential development of males and females are there recognizable stages of: A. Male responses toward pre-ovulatory urine and its specific chemical signal(s)? B. Female responses toward pre-ovulatory urine and its specific chemical signal(s)?SET III: Based on the results in the first two sets, what are the comparative ontogenetic patterns of male and female responses toward known chemical signal sources and to specific signal compounds and more generally in the display of reproductively related behaviors? These questions are investigated first by a study of female-to-male signals (IA and IIA), then female-to-female signals (IB and IIB) and finally by comparing the two developmental pathways (III). Specifically, answers are sought by: (i) Collecting urine from captive and wild female African elephants; (ii) Performing behavioral bioassays of urine samples for the responses of both male and female conspecifics; (iii) Chemically analyzing bioactive urine fractions to identify organic compounds; (iv) Bioassaying selected urinary components with captive and then wild African elephants; (vi) Observing wild African elephants for reproductive chemotactile communication.The proposed research will identify proximate chemical causes of reproductive behavior and elucidate sexually dimorphic developmental patterns of communication. This study will lay the groundwork for future investigation on male based signals and of ultimate questions on this topic. The findings may assist in the conservation of endangered elephants in practice and other species.