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Date of Award
2017
Publisher
North Dakota State University
Document Type
Dissertation
Degree Awarded
Doctor of Philosophy (PhD)
Program
Zoology
Department
Biological Sciences
College
Science and Mathematics
Faculty Advisor
Greenlee, Kendra
Description
Spring conditions stimulate development of many plants and animals after a period of winter dormancy. Climate change is predicted to cause earlier spring thaws, increasing temperature variability, and more frequent cold snaps. These conditions cause two problems for organisms. First, environmental cues may mislead organisms developing under these scenarios if temperature and photoperiod cues give conflicting information. Second, organisms outside of their overwintering stages can be less tolerant of cold exposure and may be at risk of injury or death. Little is known about the consequences of these conditions on bee species. Therefore, I examined these scenarios in a solitary bee species, Megachile rotundata. I hypothesized they would be sensitive to temperature changes to regulate spring emergence because of their cavity nesting life history where photoperiod cues likely buffered. I found light is buffered by the brood cell by approximately 80% and emergence can be synchronized by photoperiod. Furthermore, I demonstrated that M. rotundata may be more sensitive to temperature cues compared to photoperiod cues in regulating emergence. To understand how spring cold snaps during development affect adult bees, I comprehensively assayed M. rotundata cold tolerance. I discovered that cold exposure during development resulted in numerous sub-lethal effects in adult bees such as a decrease in flight performance and longevity. Furthermore, developmental cold stress affected adult thermal performance, such as chill coma recovery. Cold tolerance varies across development and the post-diapause quiescent stage was more tolerant to cold than pupal or emergence ready stages. Temperature fluctuations of spring may affect the timing of emergence but also the health of adult bees if they experienced a cold snap during development.
Recommended Citation
Bennett, Meghan Marie, "Ecophysiological Implications of Spring Conditions on the Alfalfa Leafcutting Bee, Megachile rotundata" (2017). Biological Sciences. 4.
https://digitalcommons.ndsu.edu/biological-sci/4
Rights
NDSU Policy 190.6.2
Rights Link
https://www.ndsu.edu/fileadmin/policy/190.pdf
Handle Identifier
https://hdl.handle.net/10365/27479