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)

Personality variation in a clonal insect: The pea aphid, Acyrthosiphon pisum

Individuals are often consistent in their behavior but vary from each other in the level of behavior shown. Despite burgeoning interest in such animal personality variation, studies on invertebrates are scarce, and studies on clonal invertebrates nonexistent. This is surprising given the obvious advantages of using invertebrates/clones to tackle the crucial question why such consistent behavioral differences exist. Here we show that individuals of clonal pea aphids exhibit consistent behavioral differences in their escape responses to a predator attack (dropping vs. nondropping off a plant). However, behavior was not repeatable at the clonal level. Genetically identical clones expressed various phenotypes but different clones produced different proportions of each phenotype (dropper, nondropper, and inconsistent). Manipulations of early environmental conditions had little qualitative impact on such patterns. We discuss the importance of our findings for future studies of the evolutionary and ecological consequences of personality variation

Data_Personality_Growth-continuous

Data_Personality_Growth-continuou

Data_Personality-Life-history

Data_Personality-Life-histor