Abstracts (first author)
Disposable springtails: highly plastic ageing patterns are explained by resource allocation trade-offs in Folsomia candida
Although often neglected, the evidences of senescence occurring in the wild are accumulating (1) and there is a growing interest towards a clarification of how the mortality trajectories have been shaped by the ecological conditions (2). The challenge now lies in understanding the diversity of ageing patterns in the light of evolutionary theory (3). We developed an experimental system in the laboratory to assess these questions on the small and long-living Collembola Folsomia candida (4,5). We performed long term microcosms experiments to question how mortality trajectories have been shaped on the short- and long-term by trade-offs between traits. We found that within species genetic differences in ageing patterns can be explained with differences in growth and reproductive strategies: comparison of different lineages showed that initial mortality rate and age at onset of senescence are negatively correlated - a result coherent with recent predictions based on the 'disposable soma' theory of ageing (6). We also demonstrate that plastic adjustments of major life history traits triggered by changes in resource availability even late in life lead cohorts to shift from constant mortality trajectories (negligible senescence) to accelerated senescence. Our results emphasises the need for a more integrated ecological comprehension of the effects of environment and its fluctuations to understand how natural selection shapes ageing patterns. 1. D. H. Nussey et al., Ageing Research Reviews 12, 214-25 (2013). 2. A. Baudisch, J. W. Vaupel, Science 338, 618-9 (2012). 3. M. Bronikowski et al., Science 331, 1325-8 (2011). 4. T. Tully, R. Ferrière, PLoS One 3, e3207 (2008). 5. T. Tully, A. Lambert, Evolution 65, 3013-20 (2011). 6. M. J. Wensink et al. Biogerontology 13, 197-201 (2012).