Life-history trade-offs mediate ‘personality’ variation in two colour morphs of the pea aphid, Acyrthosiphon pisum
- Life-history trade-offs are considered a major driving force in the emergence of consistent behavioural differences (personality variation); but empirical tests are scarce.
- We investigated links between a personality trait (escape response), life-history and state variables (growth rate, size and age at first reproduction, age-dependent reproductive rates, lifetime reproductive success, life span) in red and green colour morphs of clonal pea aphids, Acyrthosiphon pisum. Escape response (dropping/non-dropping off a plant upon a predatory attack) was measured repeatedly to classify individuals as consistent droppers, consistent nondroppers or inconsistents.
- Red morphs experienced stronger trade-offs between early reproduction and life span than green morphs; and red consistent (non)droppers had highest lifetime reproductive success. Red droppers followed a risk-averse life-history strategy (high late reproduction), red nondroppers a risk-prone strategy (high early reproduction), while reproductive rates were equivalent for all green behavioural types and red inconsistents.
- This suggests that red morphs suffer the highest costs of dropping (they are most conspicuous to predators), which ‘equivalates’ fitness payoffs to both risk-takers (red non-droppers) and risk-averse red droppers. The strong trade-off also means that committing to a particular lifestyle (being consistent) maximises fitness.
- Our study suggests that life-history trade-offs likely mediate personality variation but effects might depend on interactions with other organismal characteristics (here: colour morph).