RUI: Environmental and endogenous control of Limulus behavior.

该项目的总体目标是：1)以鲎（Limulus polyphemus）为模型系统，研究产生昼夜节律和周期节律的内源性过程；2)确定这两种节律如何与环境刺激和年度生殖周期协调。马蹄蟹是这些研究的绝佳对象，因为在实验室中，它们表现出清晰、可重复的潮汐和昼夜节律，可以受到环境刺激（如昼夜和潮汐变化）的影响。此外，在野外，它们的大尺寸和机动性使得用超声波遥测技术量化它们的运动成为可能。此外，它们在春季和夏季表现出与涨潮同步的独特潮间带交配行为，这一事实使研究这些行为节律在季节性基础上的差异表达成为可能。两种方法将用于收集运动活动：现场的超声波遥测和实验室的“跑轮”。超声波遥测技术将用于量化自由活动的鲎在其自然栖息地的生物节律，并确定每种节律的表达时间，以便深入了解哪些环境线索可能有助于同步每种节律。跑步轮将用于测试不同刺激在同步周期节律和昼夜节律中的作用，并测试这些节律是由单个内源性时钟控制还是由两个（或更多）独立的内源性时钟控制。这项研究的一个更广泛的影响将是直接解决潮间带海洋物种生物节律领域的一个核心问题：行为节律是由昼夜节律振荡器控制还是由昼夜节律振荡器和昼夜节律振荡器共同控制。更广泛的影响：这项研究将产生一些额外的更广泛的影响：1)这是一项RUI拨款，它将大大加强本科生在科学方面的培训，特别是在普利茅斯州立大学，这是一个培养该州许多K-12教育工作者的机构。2)重要的是，该研究提出了在一年的过程中，特别是在交配季节，调查影响limus行为的内部和外部因素。由于最近的许多研究表明，该物种在其大部分范围内（如果不是全部的话）都在减少，因此更好地了解这种在商业和生态上都很重要的物种的交配行为背后的因素至关重要。3)此外，本研究将增强我们对内部时钟和环境影响如何共同影响某些行为的表达的理解，以及这些行为在实验室和现场的不同表现。4)这项研究的结果也将有助于将limus的视觉敏感性与该物种的整体行为联系起来。5)此外，这一建议直接解决了时间生物学领域的一个重要的整体问题，即动物控制多种生理和行为过程的机制。

The overall goals of this project are: 1) to use the horseshoe crab, Limulus polyphemus, as a model system for investigating the endogenous processes that give rise to circadian and circatidal rhythms and; 2) to determine how both types of rhythms are coordinated with environmental stimuli and annual reproductive cycles. The horseshoe crab is an excellent subject for these studies because in the laboratory they exhibit clear, reproducible tidal and circadian rhythms that can be entrained to environmental stimuli (such as day/night and tidal changes). Further, in the field, their large size and mobility make it possible to quantify their movements with ultrasonic telemetry. Moreover, the fact that they exhibit a distinct intertidal mating behavior in the spring and summer that is synchronized to the high tides makes it possible to investigate how these behavioral rhythms are differentially expressed on a seasonal basis. Two methods will be used to collect locomotor activity: ultrasonic telemetry in the field and "running wheels" in the laboratory. Ultrasonic telemetry will be used to quantify the biological rhythms of freely behaving Limulus in their natural habitat and determine when each type of rhythm is expressed in order to gain insight into what environmental cues may help to synchronize each of the rhythms. Running wheels will be used to test the role of different stimuli in synchronizing circatidal vs. circadian rhythms and to test whether these rhythms are controlled by a single endogenous clock or by two (or more) separate endogenous clocks. One of the broader impacts of this study will be to directly address a central issue in the field of biological rhythms of intertidal marine species: whether behavioral rhythms are controlled by circalunidian oscillators or by both circadian and circatidal oscillators.Broader Impacts:This study will have a number of additional broader impacts: 1) This is an RUI grant and it will significantly enhance the training of undergraduate students in the sciences, especially at Plymouth State, an institution that educates many of the K-12 educators in the state. 2) Importantly, the study proposes to investigate the internal and external factors that affect Limulus behavior over the course of a year and especially during its mating season. Since many recent studies have suggested that this species is in decline over most, if not all, of its' range, a better understanding of the factors that underlie this commercially and ecologically important species' mating behavior is crucial. 3) In addition, this study will enhance our understanding of how internal clocks and environmental influences combine to influence the expression of certain behaviors, and how these behaviors are differentially manifested in the lab versus the field. 4) Results from this study will also help to link information from the large body of work done on Limulus visual sensitivity to overall behavior in this species. 5) Additionally, this proposal directly addresses an important overall issue in the field of chronobiology, the mechanisms by which animals may control multiple physiological and behavioral processes.