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Effects of constant vs. fluctuating temperatures on performance and life history of the herbivorous pest Lymantria dispar (Lepidoptera: Eribidae)

The role of temperature variation in organismal performance is understudied, but is critically important for understanding the response of biodiversity to climate change. To address this issue in herbivorous insects, I studied the direct and interactive effects of thermal regime (constant vs. fluctuating temperatures) and nutrition (dietary nitrogen) on gypsy moth (Lymantria dispar) performance under laboratory conditions. Predictions for differences between constant and fluctuating thermal conditions were derived from Jensen’s inequality, and artificial diets of differing nutritional quality were made by modifying nitrogen (casein) content. Larvae were reared in the laboratory under four temperature regimes (22°C constant, 22°C fluctuating (±6°C), 28°C constant, and 28°C fluctuating (±6°C)) and two diet treatments (high N, and low N). Gravimetric analyses were also conducted to calculate nutritional indices and assess the short-term effects of temperature and diet quality on fourth instar larvae growth efficiencies. Consistent with predictions from Jensen’s inequality, fluctuating thermal conditions significantly reduced larval performance in both sexes across ontogeny. Low quality diet also reduced performance, but interactions between diet and thermal regime were only found in early instars.

Identiferoai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-5097
Date01 January 2015
CreatorsSostak, Brendan E
PublisherVCU Scholars Compass
Source SetsVirginia Commonwealth University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations
Rights© The Author

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