Revealing complex relationships between sex, individuals' phenotype variation and social signalling in foraging strategies

In social living animals, individuals typically use two main strategies to find food: either by exploiting social information (scrounger) or relying on personal knowledge (producer). These tactics are often linked to different life-history strategies. Access to foraging patches in hierarchical social groups may constrain the use of the producer-scrounger strategies, selecting for colour ornaments to act as status badges. In sexual dimorphic species, males and females may exhibit distinct life-history strategies, with females often lacking a clear badge-of-status and occupying subordinate roles. Here we address the question of how differences in social signalling and personality influence foraging behaviour and the individuals decision to play producer or scrounger, using males and females European serins, Serinus serinus. Specifically, we analysed how individual traits such as sex, plumage colouration, and boldness, relate with foraging strategies in both solitary and social contexts. In solitary contexts, colourful individuals, regardless of sex, were faster to find food, as were bolder males and shyer females. In social contexts, less colourful males and more colourful females adopted the producer strategy, while males foraging ability was influenced by their companions boldness. Our results reveal that personality and colour differences are linked to social foraging tactics in serins in a sex-dependent manner, highlighting the adaptive value of individual traits in both sexes, and their potential implications for social evolution.