Evidence for the dilution effect in the selfish herd from fish predation on a marine insect

Foster, William A.; Treherne, J. E.

doi:10.1038/293466a0

Cited by 554 publications

(353 citation statements)

References 6 publications

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“…lesser kestrel, Falco naumanni, Serrano & Tella, 2003) but has also been shown to be influential in a wide variety of other animals (Turchin, 1987 ;Smith & Peacock, 1990;Muller, 1998;Danchin et al, 2001). A strategy of conspecific attraction may be adaptive if individuals receive direct benefits from the presence of conspecifics, such as diluted predation risk (Foster & Treherne, 1981). However, such direct benefits are not a necessity for conspecific attraction as conspecifics may be used simply as an integrative cue, reflecting the suitability of the habitat to be occupied by the species.…”

Section: ( C) Habitat Cuesmentioning

confidence: 99%

Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

2005

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Knowledge of the ecological and evolutionary causes of dispersal can be crucial in understanding the behaviour of spatially structured populations, and predicting how species respond to environmental change. Despite the focus of much theoretical research, simplistic assumptions regarding the dispersal process are still made. Dispersal is usually regarded as an unconditional process although in many cases fitness gains of dispersal are dependent on environmental factors and individual state. Condition-dependent dispersal strategies will often be superior to unconditional, fixed strategies. In addition, dispersal is often collapsed into a single parameter, despite it being a process composed of three interdependent stages : emigration, inter-patch movement and immigration, each of which may display different condition dependencies. Empirical studies have investigated correlates of these stages, emigration in particular, providing evidence for the prevalence of conditional dispersal strategies. Ill-defined use of the term ' dispersal', for movement across many different spatial scales, further hinders making general conclusions and relating movement correlates to consequences at the population level. Logistical difficulties preclude a detailed study of dispersal for many species, however incorporating unrealistic dispersal assumptions in spatial population models may yield inaccurate and costly predictions. Further studies are necessary to explore the importance of incorporating specific condition-dependent dispersal strategies for evolutionary and population dynamic predictions.

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Section: ( C) Habitat Cuesmentioning

confidence: 99%

Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

2005

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“…We then considered two contrasting selection pressures on lateralization. On one hand, individuals in large groups have a lesser risk of being targeted by predators (the so-called 'dilution' of predation risk, Foster & Treherne 1981). This favours individuals who tend to escape in the same direction as the majority, thus promoting the same direction of lateralization across the whole population.…”

Section: Introductionmentioning

confidence: 99%

Intraspecific competition and coordination in the evolution of lateralization

Ghirlanda

Frasnelli

Vallortígara

2008

Phil. Trans. R. Soc. B

213

132

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Recent studies have revealed a variety of left-right asymmetries among vertebrates and invertebrates. In many species, left-and right-lateralized individuals coexist, but in unequal numbers ('populationlevel' lateralization). It has been argued that brain lateralization increases individual efficiency (e.g. avoiding unnecessary duplication of neural circuitry and reducing interference between functions), thus counteracting the ecological disadvantages of lateral biases in behaviour (making individual behaviour more predictable to other organisms). However, individual efficiency does not require a definite proportion of left-and right-lateralized individuals. Thus, such arguments do not explain population-level lateralization. We have previously shown that, in the context of prey-predator interactions, population-level lateralization can arise as an evolutionarily stable strategy when individually asymmetrical organisms must coordinate their behaviour with that of other asymmetrical organisms. Here, we extend our model showing that populations consisting of left-and right-lateralized individuals in unequal numbers can be evolutionarily stable, based solely on strategic factors arising from the balance between antagonistic (competitive) and synergistic (cooperative) interactions.

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“…[1][2][3]). These benefits include dilution [4], encounter-dilution [5,6] and confusion effects [7][8][9][10], through which individuals benefit from reduced risk arising from the presence of con-or heterospecifics in close proximity. The selfish herd hypothesis [11] suggests a further benefit to individuals: risk for any particular individual in the group can be reduced, but at the expense of other group members, for whom risk is increased.…”

Section: Introductionmentioning

confidence: 99%

‘Selfish herds’ of guppies follow complex movement rules, but not when information is limited

Kimbell¹,

Morrell²

2015

Proc. R. Soc. B.

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Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well understood, and how environmental factors affect the use of these rules even less so. Here, we evaluate the success of different movement rules, by comparing their predictions with the movement seen when shoals of guppies (Poecilia reticulata) form under the threat of predation. We repeated the experiment in a turbid environment to assess how the use of the movement rules changed when visual information is reduced. During a simulated predator attack, guppies in clear water used complex rules that took multiple neighbours into account, forming compact groups. In turbid water, the difference between all rule predictions and fish movement paths increased, particularly for complex rules, and the resulting shoals were more fragmented than in clear water. We conclude that guppies are able to use complex rules to form dense aggregations, but that environmental factors can limit their ability to do so.

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Evidence for the dilution effect in the selfish herd from fish predation on a marine insect

Cited by 554 publications

References 6 publications

Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

Intraspecific competition and coordination in the evolution of lateralization

‘Selfish herds’ of guppies follow complex movement rules, but not when information is limited

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