The Development of Adaptive Embryo Behavior

许多物种的胚胎以对生存至关重要的方式评估和回应环境。胚胎生命的许多特征和挑战在动物中广泛共享，但青蛙卵特别容易研究。像卵囊这样的结构保护和约束了胚胎，形成了成本和收益的权衡。在孵化后，动物进入了一个新的环境，有新的危险和资源。什么时候孵化是胚胎根据环境因素做出的重要决定。孵化也是胚胎必须完成的一项生理壮举。随着胚胎的发育，评估线索、离开卵子以及在卵子外生存的能力都会发生变化。因此，在同样的条件下，胚胎能做什么和它们应该做什么来生存也会发生变化。该项目将研究发育如何以及为什么会改变行为，使用红眼树蛙的胚胎，这些胚胎过早孵化高达40%，以逃避对卵的威胁。它将评估成熟的重要性、与能力相匹配的决策的适应性变化、胚胎学习以及胚胎如何使用两种信息；氧气供应的简单线索和复杂的振动可以预示捕食者的攻击。它将提高我们对胚胎生命、行为发育以及动物如何使用不同种类的信息来做决定的理解，包括非常重要但人们知之甚少的振动信息。胚胎的适应性行为是容易接近和吸引人的，因此是科学教育和推广的理想选择。该项目将为研究生和本科生提供跨学科的生物工程培训，并为美国学生和拉丁美洲实习生提供新热带研究和跨文化体验。pi将与媒体、博物馆和动物园合作，广泛传播结果。他们将为教师提供研究经验，并为各级教育工作者开发在线多媒体资源。该项目开发的新方法和工具将促进胚胎行为和动物对振动线索的反应的其他研究。本项目是对红眼树蛙环境提示孵化的发展和调控的综合研究，其中多种选择权衡决定了孵化时间。胚胎利用至少两种感官模式的线索来决定是否孵化。年龄较大的胚胎更容易孵化，但即使是30%的早产胚胎有时也会在几秒钟内孵化。该项目将评估：I)孵化的速度和成功率如何随着效应器的发展而变化，重点是孵化腺；II)传感器的发展如何改变对线索和线索特性的敏感性，解决内耳和侧线机械接受的发育变化与更一致的、早期发展的氧气感知；III)如何通过发育变化的权衡、阶段特异性选择的历史和胚胎早期的经验来形成对简单缺氧信号和复杂的振动、潜在的触觉、物理干扰信号的反应的孵化决策规则。该团队将使用(a)组织学和显微镜来描述形态学变化，(b)呼吸测量来评估代谢变化，(c)前庭-眼反射测量来评估耳功能，(d)宏观录像来分析胚胎行为和孵化性能。他们将评估在可控缺氧、振动回放和捕食者攻击下孵化的个体发生变化，并开发新的回放方法来分离物理干扰线索的运动和触觉成分。机械感觉刺激和缺氧是跨分类群孵化的常见线索。此外，振动信号和线索在许多其他情况下，在以后的生活中通知行为，氧气的可用性塑造了许多水生动物的行为。红眼树蛙胚胎的结果将促进我们对行为发育和动物信息使用的更广泛的理解。数据集将存入DRYAD。外展材料，包括图片和视频，将被张贴在Warkentin的实验室网站上，或者被贡献到生命百科全书或国家生物教师协会的网络资源页面上。

Embryos of many species assess and respond to their environment in ways that matter for survival. Many features and challenges of embryonic life are broadly shared across animals, but frog eggs are particularly tractable to study. Structures such as egg capsules protect and constrain the embryo inside, creating a trade-off of costs and benefits. Upon hatching, animals enter a new environment, with both new dangers and resources. When to hatch is an essential decision embryos make, based on environmental cues. Hatching is also a physical feat that embryos must perform. The ability to assess cues, to exit the egg, and to survive outside the egg all change as embryos develop. Thus, under the same conditions, what embryos can do and what they should do to survive also changes. This project will examine how and why development changes behavior, using embryos of red-eyed treefrogs that hatch up to 40% prematurely to escape threats to the egg. It will assess the importance of maturation, adaptive changes in decisions matched to abilities, embryonic learning, and how embryos use two kinds of information; simple cues of oxygen availability and complex vibrations that can indicate predator attack. It will improve our understanding of embryo lives, behavioral development, and how animals use different kinds of information to make decisions, including broadly important but poorly understood vibrational information. The adaptive behavior of embryos is accessible and appealing, and thus ideal for scientific education and outreach. This project will offer interdisciplinary biology-engineering training for graduate and undergraduate students, as well as Neotropical research and cross-cultural experiences for US students and Latin American interns. The PIs will work with the media, museums, and zoos to disseminate results broadly. They will offer research experiences for teachers and develop online multimedia resources for educators at multiple levels. New methods and tools developed by this project will facilitate other research on embryo behavior and animal responses to vibrational cues. This project is an integrative study of the development and regulation of environmentally cued hatching in red-eyed treefrogs, for which multiple selective trade-offs shaping hatching timing are known. Embryos use cues in at least two sensory modalities for their hatching decision. Older embryos hatch more readily, but even 30%-premature embryos sometimes hatch within seconds of a cue. This project will assess: I) how the speed and success of hatching change across effector development, focusing on hatching glands; II) how sensor development changes sensitivity to cues and cue properties, addressing developmental changes in mechanoreception by the inner ear and lateral line vs. more consistent, early developed, oxygen sensing; and III) how hatching decision rules for responses to simple hypoxia cues and complex vibrational, and potentially tactile, physical disturbance cues are shaped by developmentally changing trade-offs, a history of stage-specific selection, and the earlier experiences of embryos. The team will use (a) histology and microscopy to characterize morphological changes, (b) respirometry to assess metabolic changes, (c) measures of vestibulo-ocular reflexes to assess otic function, and (d) macro-videography to analyze embryo behavior and hatching performance. They will assess ontogenetic changes in hatching under controlled hypoxia, vibration playback, and predator attacks, and develop new playback methods for separating motion and tactile components of physical disturbance cues. Mechanosensory stimuli and hypoxia are common cues for hatching across taxa. Moreover, vibrational signals and cues inform behavior in many other contexts, later in life, and oxygen availability shapes the behavior of many aquatic animals. Results from red-eyed treefrog embryos will advance our understanding of behavioral development and animal information use more broadly. Datasets will be deposited in DRYAD. Outreach materials, including images and video, will be posted on Warkentin's lab website or contributed to the Encyclopedia of Life or National Association of Biology Teachers web resource page.