The plastic fly: the effect of sustained fluctuations in adult food supply on life-history traits.
Bottom Line: Remarkably, both the manner and extent to which life-history traits varied in relation to food depended on whether flies initially experienced high or low food after eclosion.We therefore conclude that the expression of life-history traits in adult life is affected not only by adult plasticity, but also by early adult life experiences.This is an important but often overlooked factor in studies of life-history evolution and may explain variation in life-history experiments.
Affiliation: Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands; Evolutionary Biology Group, Leiden University, Leiden, The Netherlands; Institute for Ageing and Health, Newcastle University, Campus for Aging and Vitality, Newcastle Upon Tyne, UK.Show MeSH
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Mentions: A higher proportion of flies that were weighed died in the first 4 days of the experiment, whereas this did not happen for the group of flies that were not weighed (256 of the 609, 42.0% of the weighed flies, 61 of the 638, 9.6% of the unweighed flies, = 173.32, P < 0.001, see Fig. S1, Table S1). We tested whether the number of deaths was distributed heterogeneously over the food treatment groups. This was not the case ( = 2.42, P = 0.79 for unweighed flies, = 7.25, P = 0.20 for weighed flies), and therefore, the analysis was conducted by removing the data from the first 4 days to improve the fit of the Cox proportional hazard tests. The survival analysis using food treatment and weighing treatment as explanatory variables indicated that the two-way interaction between food and weighing, and weighing as a main effect were not significant (Z = 0.956, P = 0.34, for the latter). The survival curves (Fig.1) and hazard ratios per term (Table1) indicate that the survival of the CL flies is significantly lower than all flies in all other treatments. Although the slow yoyo flies that started high did not have a higher survival compared to the constant high flies, they did have an improved survival compared to all the other groups (Table1). All other groups of flies, besides the CL flies, were not significantly different in survival compared to the CH flies. Therefore, flies that received sustained fluctuations had an intermediate survival, but significantly higher than the constant low flies.
Affiliation: Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands; Evolutionary Biology Group, Leiden University, Leiden, The Netherlands; Institute for Ageing and Health, Newcastle University, Campus for Aging and Vitality, Newcastle Upon Tyne, UK.