Empirical evidence of senescence in adult damselflies (Odonata: Zygoptera

1. Age-dependent increases in mortality have been documented in a variety of species of insect under laboratory conditions. However, while strong statistical evidence has been presented for senescence in vertebrate populations in the wild, we know little about the rate and shape of senes-cence in wild populations of insects. 2. Odonates (damselflies and dragonflies) provide excellent candidate species for evaluating demo-graphic senescence as they are large enough to be marked individually and they are easily re-sighted without recapture. The prevailing opinion – based entirely on qualitative examination of the declines in log numbers alive with time since marking – is that odonates exhibit age-indepen-dent daily survivorship. 3. Here, we examine mark–recapture data on the Azure Damselfly Coenagrion puella over two consecutive seasons. For the first time, we evaluate and compare the fit of quantitative models that not only account for weather-dependent daily variation in daily re-sighting rates, but also age-dependent variation in daily survivorship. 4. Models with age-dependent declines in daily survivorship provide a more parsimonious expla-nation for the data than similar models without these age-dependent effects. In general, models i