Article ID Journal Published Year Pages File Type
2842810 Journal of Thermal Biology 2015 9 Pages PDF
Abstract

•Beetles developed the fastest and had the greatest body mass in constant 30 °C.•This pattern was reversed in constant 25 °C•Fluctuations reduced impact of temperature on development time.•Fluctuations caused differences in body mass to disappear.•Females acquired more mass, in the same development time.

Temperature has profound effects on biological functions at all levels of organization. In ectotherms, body size is usually negatively correlated with ambient temperature during development, a phenomenon known as The Temperature-Size Rule (TSR). However, a growing number of studies have indicated that temperature fluctuations have a large influence on life history traits and the implications of such fluctuations for the TSR are unknown. Our study investigated the effect of different constant and fluctuating temperatures on the body mass and development time of red flour beetles (Tribolium castaneum Herbst, 1797); we also examined whether the sexes differed in their responses to thermal conditions.We exposed the progeny of half-sib families of a T. castaneum laboratory strain to one of four temperature regimes: constant 30 °C, constant 25 °C, fluctuating with a daily mean of 30 °C, or fluctuating with a daily mean of 25 °C. Sex-specific development time and body mass at emergence were determined.Beetles developed the fastest and had the greatest body mass upon emergence when they were exposed to a constant temperature of 30 °C. This pattern was reversed when beetles experienced a constant temperature of 25 °C: slowest development and lowest body mass upon emergence were observed. Fluctuations changed those effects significantly – impact of temperature on development time was smaller, while differences in body mass disappeared completely. Our results do not fit TSR predictions. Furthermore, regardless of the temperature regime, females acquired more mass, while there were no differences between sexes in development time to eclosion. This finding fails to support one of the explanations for smaller male size: that selection favors the early emergence of males. We found no evidence of genotype × environment interactions for selected set of traits.

Related Topics
Life Sciences Agricultural and Biological Sciences Agricultural and Biological Sciences (General)
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