Do faster starts increase the probability of evading predators?

Abstract

Summary1. Nearly all fish evade predation strikes by rapidly accelerating out of the strike path, a behaviour called the fast-start evasion response. The many studies investigating morphological, behavioural and ecological correlates of fast-start performance assume that faster starts increase the probability of evasion. 2. We tested this faster-start hypothesis by measuring the effect of acceleration ability on evasion outcome (success, failure) in Guppies ( Poecilia reticulata ) evading the strike of a natural predator, the Pike Cichlid ( Crenicichla alta ). 3. Four parameters affect evasion outcome: two parameters important to the predatorprey interaction but not to the faster-start hypothesis -(1) the time required to reach the prey by the striking predator (measured by the initial distance between predator and prey and strike velocity), (2) the evasion path of the prey relative to the strike path of the predator; and two parameters relevant to the faster-start hypothesis -(1) the ability of the prey to generate rapid tangential acceleration (measured by net distance travelled, maximum velocity, and maximum acceleration), and (2) the ability of the prey to rapidly rotate during the initial stage of the fast start. 4. On average, a one standard deviation increase in fast-start performance increases the odds of surviving a predation strike 2·3-fold. These results support the assumption that faster starts increase the probability of successfully evading a predation strike.

A small increase in UV-B increases the susceptibility of tadpoles to predation

“…In contrast to the effects of increased UV-B, exposure to PCC caused tadpoles to have increased locomotor performance (figure 2a) and longer survival times in a predator environment (figure 2b). This suggests that an increase in locomotor performance does confer some benefit to survival in a predator environment as one would expect [27], but with regard to the effects of UV-B, there are clearly additional factors that need to be considered when investigating predator-prey interactions. Consideration of behavioural defence mechanisms and the energetic costs associated with exposure to UV-B may provide an explanation for the observed reduction in survival time of tadpoles exposed to the high UV-B treatment.…”

Predator-induced morphology enhances escape locomotion in crucian carp

“…The most common way of avoiding predation, however, is the escape response, a burst swimming movement shown by most fishes when attacked by a predator (Domenici & Blake 1997). Various characteristics of this response were shown to be fundamental for avoiding predation, such as reaction distance, escape path, distance-derived variables (such as velocity and acceleration) and turning rates ( Walker et al 2005). Previous work has shown that certain morphological defences, such as changes in body shape, can be induced by the presence of predators (Brönmark & Miner 1992).…”

“…However, given the trade-offs existing between different body shapes and various swimming functions (Webb 1984a), an induced morphological change may not necessarily imply a cost for all locomotor activities. A large body depth may enhance the acceleration performance during escape locomotion, which is considered crucial for avoiding predation in most fish species (Weihs 1973;Webb 1984a;Domenici & Blake 1997;Godin 1997;Walker et al 2005). Based on the idea of a trade-off between a deep and a shallow body as linked to accelerator versus cruiser characteristics (Webb 1984a), we used two morphs of crucian carp to test the prediction that predatorinduced deep-bodied fishes have higher locomotor performance in escape manoeuvres than shallow-bodied fishes.…”

Speciation through the lens of biomechanics: locomotion, prey capture and reproductive isolation

“…While applicable to a wide range of animal systems, we focus on fishes because of their extensive ecological, phylogenetic and phenotypic diversity, as well as their prevalence as model systems for studying speciation, many-to-one mapping, and biomechanics. Predator-prey interactions in fishes have been a major focus of research over the past several decades [28,29], where survival depends on both the ability to escape from predators and to catch prey [30]. Locomotor and feeding traits underlie predator-prey interactions, and both respond to selection and contribute to RI [31,32], making predator-prey interactions central to the study of speciation.…”