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Factors Affecting Metabolism During Non-Feeding Stages in Insects

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Cambron, Liz Doralyn
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Factors Affecting Metabolism During Non-Feeding Stages in Insects (4.900Mb)
Liz Cambron dissertation video (123.8Mb)
Abstract
Although feeding is important for optimal development and growth in insects, there are several points during the insect life cycle that are non-feeding: metamorphosis, pupation, and overwintering. Non-feeding periods also occur in response to internal cues, such as feedback from nutrient thresholds and immune responses being activated. Additionally, as an insect goes through different developmental stages, its nutritional requirements change in response to or in preparation for non-feeding periods. Most physiological responses like feeding are regulated through an interconnection of pathways, but how these networks change in response to different energy demands, such as immune challenges or changes in metabolism, is poorly understood. One significant pathway that is involved in regulating several physiological processes is the insulin signaling pathway. In my dissertation research, I tested hypotheses explaining the regulation of physiological processes during non-feeding periods in two agriculturally relevant insects, Manduca sexta and Megachile rotundata. First, I investigated how internal cues such as dietary lipid content and immune challenges cause non-feeding periods in M. sexta. Then, I investigated how insulin signaling regulates development during a non-feeding period like overwintering changes in M. rotundata. Since the insulin signaling (IIS) pathway is critical for development and growth, I focused on testing if this pathway plays a role in regulating non-feeding periods. My research showed that increased dietary lipid content causes a cessation of feeding, which suggests there is a possible lipid threshold that when reached, causes M. sexta to switch from lipid consumption for storage to lipid excretion. When looking at another cue like immune challenges, my results showed that during a bacterial infection, a Toll-mediated suppression of IIS pathway may be regulating feeding and causing a non-feeding period exhibited as sickness-induced anorexia. Lastly, my results also showed that the IIS pathway is suppressed in overwintering M. rotundata, and that this process can change in response to temperature. Overall, my dissertation research showed that the insulin signaling pathway and nutrient content play a vital role in regulating non-feeding periods. Investigating insulin signaling, lipid metabolism, and innate immunity in these species closes a gap in knowledge of invertebrate development.
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https://hdl.handle.net/10365/31868
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Student Focused, Land Grant, Research Institution

  • Campus Map
    • Campus Map (pdf)
    • Building list
    • Campus Offices
  • Equity
  • Employment
  • Phone/Email Directory
  • Online Services
    • Blackboard
    • One Stop
    • Campus Connection
    • IT Help Desk
    • Libraries
    • Email
    • Student Success Collaborative
  • Registration And Records
    • Course Schedule
    • Dates and Deadlines
North Dakota State University - Libraries
Circulation: (701) 231-8888 | Reference: (701) 231-8886
Administration: (701) 231-8753
Main Library address: 1201 Albrecht Boulevard
Mailing address: Dept #2080 PO Box 6050, Fargo, ND 58108-6050
Site manager: Site manager
Contact Us | Send Feedback