Metamorphic Development Of Manduca Sexta: An In Vivo Integrative Approach To Studying Whole Animal Physiology

METAMORPHIC DEVELOPMENT OF MANDUCA SEXTA: AN IN VIVO INTEGRATIVE APPROACH TO STUDYING WHOLE ANIMAL PHYSIOLOGY Ayesa Kaur, Ph.D. Cornell University 2013 Multicellular organisms have evolved specialized tubular structures to transport gases and liquids throughout the body. For vertebrates, such structures include the trachea, bronchi, bronchioles and blood vessels. The genesis of these elaborate tubular structures, known as tracheogenesis for trachea and angiogenesis for blood vessels, has received a great deal of attention in the last decade in many fields, including developmental biology and oncology. It has become increasingly important to understand how the genesis of these structures is regulated to produce a functional organ system where the transport capacity matches the physiological needs of the organism. In particular, investigators have asked when do new branches arise, what determines the direction of growth, what specifies the formation of the next generation of branches, and how do tubular networks fuse to create functional organs. This PhD. dissertation research attempts to address some of the above questions in the context of tracheogenesis, using a unique animal model, a moth Manduca sexta. During a relatively short, on average 19 day, cycle of development known as pupal metamorphosis, the respiratory system of this invertebrate remodels completely to accommodate new adult organ systems such as an extensive tracheal network and thoracic fight muscles. The goal of this research is to understand and establish the dynamics of tracheogenesis and organ development by conducting a longitudinal study of pupal metamorphosis, in vivo, using minimally invasive diagnostic imaging technology of micro-computerized tomography (Micro-CT). Interestingly, our animal model, the moth, is also capable of surviving conditions of anoxia that would be lethal for humans. As a result, another important aim of this research was to establish the role of unusual structures and adaptations specific to the pupal respiratory system of Manduca (e.g., airsacs) during metamorphosis via Micro-CT imaging and flow respiratory. This dissertation also describes the successful application of the information on tissue morphogenesis acquired from Micro-CT images to construct an efficient protocol for implantation of MEMS probes into Manduca pupae. This project aimed at creating insect bioborgs where the flight capacity of insects, some of nature’s best fliers, was harnessed by surgically integrating micro actuators inside or on an insect body. In my aim to design inquiry based lessons and low-cost experimental protocols to enhance the science curriculum for the CLIMB GK-12 education program, I combined advanced imaging systems such as MCT with traditional bio laboratory methods of bioinquiry and respirometry, to teach students important concepts on developmental biology, anatomy, ecology and evolution. By posing real life examples and problems, such as global warming and resulting changes in physiology, ecology and habitat of insect pests, I attempted to link what we learn in a classroom to dynamic physiological phenomenon occurring in organisms in our surrounding environment.