A Major Measure Of Biological Fitness

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A major measure of biological fitness in a population is the fecundity, or reproductive success rate, of female organisms (Berger et al, 2008). For insects in particular many factors influence the number of eggs produced during the lifetime of a female. One key factor in insect reproduction is the ambient environmental temperature. Insects are ectothermic and therefore rely on their environment to provide the heat needed to carry out normal reproductive functions. Ambient heat dependence for insects has been thought to have a greater effect on fertility success than other contributing factors such as increased female body size. Studies by Berger and others have shown that the European speckled wood butterfly, Pararge aegeria, can only reproduce in the temperature range of 8°C and 14 °C even when controlling for larger female body sizes. The findings of the study suggest that temperature can limit insect reproduction in two specific ways. First, the development of the egg may be inhibited by temperature ranges that are outside the preferred range of the insect. Second, the female’s range of time she is able to lay eggs is reduced when the temperature of the immediate environment is not conducive to the survival of her offspring (Berger et al, 2008). Thus, temperature is a paramount factor when considering the success rate of many insect species.
Other studies have shown the importance of temperature on reproductive success of certain insects and the implications that
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