Phenotypic resonance from a single meal in an insectivorous lizard.

Environmental variations are usually thought to require a nonanecdotal intensity or duration to have major effects on individuals and evolutionary outputs. However, environmental variations of weak intensity and short duration could be of major importance when they influence key targets or critical stages. Because conditions experienced early in life can be critical determinants of life history trajectories, especially early nutrition, we tested this hypothesis by experimentally manipulating the first meal of life in the lizard Zootoca vivipara. The species is a live-bearing lizard without parental care, and it consumes small arthropods. Neonates face a great challenge in acquiring their first meal, as is the case in many species that develop skills through learning to capture live prey. We show that this single meal had an overall and long-lasting impact. Effects on dispersal arose within 10 days, and we found effects 1-2 months later on growth, recapture probability, and juvenile survival. Interestingly, we detected effects on reproduction up to 2 years later. Such a "phenotypic resonance" reveals that the influence of small and ephemeral events should not be neglected by evolutionary biologists.