Author: Sharon Fern ClemmensenPublisher:
ISBN:
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Languages : en
Pages :
Book Description
ABSTRACT: The majority of ectotherms exhibit a pattern of decreasing size with increasing temperature, known as the temperature-size rule (TSR). Despite the extent of this pattern, the effect of seasonality on the TSR is poorly understood. We use Helicoverpa zea (corn earworm) to determine the effects of seasonal dormancy programming (pupal diapause) on the TSR, lipid storage, and larval development. H. zea did not conform to the TSR over the seasonally-relevant temperature range where pupae entered diapause. H. zea increased in both lipid and lean mass with increasing temperature for 16°C to 20°C in both diapause-destined and non-diapause treatments. Diapausing H. zea were fatter across temperatures without having more lean mass, and the slope of the relationship between lean mass and temperature was not different between diapausing and non-diapausing pupae. Across temperatures, diapause-destined larvae increased their consumption but not their digestive efficiency, supporting increased pupal lipid mass. We found threshold weights for entrance to and exit from diapause, and diapause-destined larvae altered the timing for pupation, further reinforcing the importance of size to seasonal diapause. In conclusion, predictions of seasonal effects on body size must incorporate cues other than temperature, to avoid inaccurate or incomplete models of development and body size.