The effects of familiarity on escape responses in the Trinidadian guppy (Poecilia reticulata)

Abstract

Predation is the main driver of mortality during early life stages. The ability to avoid and evade potential threats is, therefore, favoured to evolve during the early stages of life. It is also during these early stages that the process of familiarization occurs. It has long been recognized that associating with familiar individuals confers anti predator benefits. Less, however, is known about how predator evasion is affected by social experience during early stages. In this study we test the hypothesis that familiarization acquired during early life stages improves anti predator escape responses. Using the Trinidadian guppy we examine the effect of different early social conditions in the three main components of predator evasion. Using high-speed motion analysis we compared the responsiveness, reactive distance and magnitude of the response (maximum speed, maximum acceleration and distance) of the response to a visual stimulus in groups composed either of familiar or non-familiar individuals. Surprisingly, groups composed by familiar individuals were less responsive than groups of unfamiliar individuals. It is plausible that familiarity equips individuals with better skills to accurately assess the threat avoiding false alarms. Reactive distance and magnitude of response were more dependent on individual size than on familiarity. Larger individuals reached higher maximum speeds and total distances in their escape response. Our approach allowed us to tease apart which aspects of an escape response are more likely to be influenced by early social conditions. 19 Predation is the main driver of mortality during early life stages. The ability to avoid and evade 20 potential threats is, therefore, favoured to evolve during the early stages of life. It is also during 21 these early stages that the process of familiarization occurs. It has long been recognized that 22 associating with familiar individuals confers antipredator benefits. Less, however, is known 23 about how predator evasion is affected by social experience during early stages. In this 24 study we test the hypothesis that familiarization acquired during early life stages improves 25 antipredator escape responses. Using the Trinidadian guppy we examine the effect of different 26 early social conditions in the three main components of predator evasion. Using high-speed 27 motion analysis we compared the responsiveness, reactive distance and magnitude of the 28 response (maximum speed, maximum acceleration and distance) of the response to a visual 29 stimulus in groups composed either of familiar or non-familiar individuals. Surprisingly, groups 30 composed by familiar individuals were less responsive than groups of unfamiliar individuals. It 31 is plausible that familiarity equips individuals with better skills to accurately assess the threat 32 avoiding false alarms. Reactive distance and magnitude of response were more dependent on 33 individual size than on familiarity. Larger individuals reached higher maximum speeds and total 34 distances in their es...

Maternal predator‐exposure affects offspring size at birth but not telomere length in a live‐bearing fish

“…First, females responded to predator models and to the alarm cue by showing the typical antipredator behavior observed in natural conditions and as found in previous laboratory experiments (Evans et al, ; Heathcote et al, ). Second, we found a significant reduction of offspring size at birth, which suggests that the stress experienced by the mothers during the gestation negatively impacted offspring as a reduced size constrains escape performance (Dial et al, ; Wolcott, Ojanguren, & Barbosa, ) and survival (Henrich, ) in fishes. Our result aligns with previous evidence in fishes in which the exposure to glucocorticoids (such as the cortisol) in the mother, and in turn in their eggs (Hwang, Wu, Lin, & Wu, ), was followed by the production of smaller offspring compared with offspring produced by undisturbed mothers (Eriksen et al, ; McCormick, ).…”

Social familiarity improves fast-start escape performance in schooling fish

“…Intrinsic factors, such as group size and phenotypic composition (e.g. body size, personality), may alter group communication and decision-making 25,36,[75][76][77] . Extrinsic factors, such as competition for food resources 78 , heterogeneity in predation pressure 79 , habitat complexity 36 , and water depth 80 can also shift the physical and social network structure of fish schools.…”