All Outputs (69)

Balancing the dilution and oddity effects: Decisions depend on body size (2011)
Journal Article
Morrell, L. J., Askwith, B., Rodgers, G. M., & Ward, J. R. (2011). Balancing the dilution and oddity effects: Decisions depend on body size. PLoS ONE, 6(7), e14819. https://doi.org/10.1371/journal.pone.0014819

Background Grouping behaviour, common across the animal kingdom, is known to reduce an individual's risk of predation; particularly through dilution of individual risk and predator confusion (predator inability to single out an individual for attack)... Read More about Balancing the dilution and oddity effects: Decisions depend on body size.

Measuring marginal predation in animal groups (2011)
Journal Article
Hirsch, B. T., & Morrell, L. (2011). Measuring marginal predation in animal groups. Behavioral ecology, 22(3), 648-656. https://doi.org/10.1093/beheco/arr026

Predation is a major pressure that shapes animal sociality, but predation risk is not homogenous within groups. Animals located on the group edge typically face an increased threat of predation, although different patterns have been reported. We crea... Read More about Measuring marginal predation in animal groups.

Spatial positioning in the selfish herd (2010)
Journal Article
Morrell, L. J., Ruxton, G. D., & James, R. (2011). Spatial positioning in the selfish herd. Behavioral ecology, 22(1), 16-22. https://doi.org/10.1093/beheco/arq157

The antipredator benefits of grouping are relatively well understood; however, predation risk often differs for individuals that occupy different positions within a group. The selfish herd hypothesis describes how individuals can reduce risk of preda... Read More about Spatial positioning in the selfish herd.

The temporal selfish herd: predation risk while aggregations form (2010)
Journal Article
Morrell, L. J., Ruxton, G. D., & James, R. (2011). The temporal selfish herd: predation risk while aggregations form. Proceedings of the Royal Society B: Biological Sciences, 278(1705), 605-612. https://doi.org/10.1098/rspb.2010.1605

The hypothesis of the selfish herd has been highly influential to our understanding of animal aggregation. Various movement strategies have been proposed by which individuals might aggregate to form a selfish herd as a defence against predation, but... Read More about The temporal selfish herd: predation risk while aggregations form.

Colour change and assortment in the western rainbowfish (2010)
Journal Article
Rodgers, G. M., Kelley, J. L., & Morrell, L. J. (2010). Colour change and assortment in the western rainbowfish. Animal behaviour, 79(5), 1025-1030. https://doi.org/10.1016/j.anbehav.2010.01.017

Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual's risk of predation, for example through predator confusion. Theory predicts that individuals that are different in appearance to the rest of the group a... Read More about Colour change and assortment in the western rainbowfish.

Unpredictability in food supply during early life influences boldness in fish (2010)
Journal Article
Chapman, B. B., Krause, J., & Morrell, L. J. (2010). Unpredictability in food supply during early life influences boldness in fish. Behavioral ecology, 21(3), 501-506. https://doi.org/10.1093/beheco/arq003

Behavioral variation has been documented both between and within populations in a variety of traits. Many of these behavioral traits are phenotypically plastic and are conditional on the early environment an animal experiences, yet despite this the r... Read More about Unpredictability in food supply during early life influences boldness in fish.

Behavioural consequences of sensory plasticity in guppies (2010)
Journal Article
Chapman, B. B., Morrell, L. J., Tosh, C. R., & Krause, J. (2010). Behavioural consequences of sensory plasticity in guppies. Proceedings of the Royal Society B: Biological Sciences, 277(1686), 1395-1401. https://doi.org/10.1098/rspb.2009.2055

Sensory plasticity, whereby individuals compensate for sensory deprivation in one sense by an improvement in the performance of an alternative sense, is a well-documented phenomenon in nature. Despite this, the behavioural and ecological consequences... Read More about Behavioural consequences of sensory plasticity in guppies.

Plasticity in male courtship behaviour as a function of light intensity in guppies (2009)
Journal Article
Chapman, B. B., Morrell, L. J., & Krause, J. (2009). Plasticity in male courtship behaviour as a function of light intensity in guppies. Behavioral Ecology and Sociobiology, 63(12), 1757-1763. https://doi.org/10.1007/s00265-009-0796-4

The environment is profoundly important in shaping many aspects of animal phenotype, including courtship and mating behaviours. Courtship displays rely upon the transmission of visual information from the signaller to the receiver, which means they a... Read More about Plasticity in male courtship behaviour as a function of light intensity in guppies.

The effect of prey density on predators: Conspicuousness and attack success are sensitive to spatial scale (2009)
Journal Article
Ioannou, C. C., Morrell, L. J., Ruxton, G. D., & Krause, J. (2009). The effect of prey density on predators: Conspicuousness and attack success are sensitive to spatial scale. The American naturalist, 173(4), 499-506. https://doi.org/10.1086/597219

In contrast to the numerous studies that have examined the response of predators to prey group size, little is known about how prey density affects prey detection and the accuracy of attacks. We demonstrate that increasing the density of Daphnia magn... Read More about The effect of prey density on predators: Conspicuousness and attack success are sensitive to spatial scale.

Does defection during predator inspection affect social structure in wild shoals of guppies? (2008)
Journal Article
Thomas, P. O. R., Croft, D. P., Morrell, L., Davis, A., Faria, J. J., Dyer, J. R. G., Piyapong, C., Ramnarine, I., Ruxton, G. D., & Krause, J. (2008). Does defection during predator inspection affect social structure in wild shoals of guppies?. Animal behaviour, 75(1), 43-53. https://doi.org/10.1016/j.anbehav.2007.06.004

Reciprocal altruism has been proposed as a possible mechanism for the evolution of cooperative behaviour. However, very few investigations have tested predictions of reciprocity in wild animal populations. In the current investigation we simulated de... Read More about Does defection during predator inspection affect social structure in wild shoals of guppies?.

Risk-sensitive antipredator behavior in the Trinidadian guppy, Poecilia reticulata (2008)
Journal Article
Botham, M. S., Hayward, R. K., Morrell, L. J., Croft, D. P., Ward, J. R., Ramnarine, I., & Krause, J. (2008). Risk-sensitive antipredator behavior in the Trinidadian guppy, Poecilia reticulata. Ecology, 89(11), 3174-3185. https://doi.org/10.1890/07-0490.1

The comparative approach has become a powerful tool for understanding how predation has shaped prey behavior. In this study we recorded the occurrence of common aquatic predator species and their densities in seven natural populations of Trinidadian... Read More about Risk-sensitive antipredator behavior in the Trinidadian guppy, Poecilia reticulata.

Shoal composition determines foraging success in the guppy (2008)
Journal Article
Dyer, J. R. G., Croft, D. P., Morrell, L. J., & Krause, J. (2009). Shoal composition determines foraging success in the guppy. Behavioral ecology, 20(1), 165-171. https://doi.org/10.1093/beheco/arn129

The composition of an animal group can impact greatly on the survival and success of its individual members. Much recent work has concentrated on behavioral variation within animal populations along the bold/shy continuum. Here, we screened individua... Read More about Shoal composition determines foraging success in the guppy.

Association patterns and foraging behaviour in natural and artificial guppy shoals (2008)
Journal Article
Morrell, L. J., Croft, D. P., Dyer, J. R. G., Chapman, B. B., Kelley, J. L., Laland, K. N., & Krause, J. (2008). Association patterns and foraging behaviour in natural and artificial guppy shoals. Animal behaviour, 76(3), 855-864. https://doi.org/10.1016/j.anbehav.2008.02.015

Animal groups are often nonrandom assemblages of individuals that tend to be assorted by factors such as sex, body size, relatedness and familiarity. Laboratory studies using fish have shown that familiarity among shoal members confers a number of be... Read More about Association patterns and foraging behaviour in natural and artificial guppy shoals.

Optimal individual positions within animal groups (2008)
Journal Article
Morrell, L., & Romey, W. L. (2008). Optimal individual positions within animal groups. Behavioral ecology, 19(4), 909-919. https://doi.org/10.1093/beheco/arn050

Animal groups are highly variable in their spatial structure, and individual fitness is strongly associated with the spatial position of an animal within a group. Predation risk and food gains are often higher at the group peripheries; thus, animals... Read More about Optimal individual positions within animal groups.

Mechanisms for aggregation in animals: Rule success depends on ecological variables (2007)
Journal Article
Morrell, L. J., & James, R. (2008). Mechanisms for aggregation in animals: Rule success depends on ecological variables. Behavioral ecology, 19(1), 193-201. https://doi.org/10.1093/beheco/arm122

Under the threat of predation, animals often group tightly together, with all group members benefiting from a reduction in predation risk through various mechanisms, including the dilution, encounter-dilution, and predator confusion effects. Addition... Read More about Mechanisms for aggregation in animals: Rule success depends on ecological variables.

Early interactions with adults mediate the development of predator defenses in guppies (2007)
Journal Article
Chapman, B. B., Morrell, L. J., Benton, T. G., & Krause, J. (2008). Early interactions with adults mediate the development of predator defenses in guppies. Behavioral ecology, 19(1), 87-93. https://doi.org/10.1093/beheco/arm111

Antipredator defenses in many species have been shown to exhibit phenotypic plasticity in response to variable predation risk. Some evidence suggests that in certain species adults act as proxy predators, triggering the development of adaptive defens... Read More about Early interactions with adults mediate the development of predator defenses in guppies.

Consensus decision making in human crowds (2007)
Journal Article
Dyer, J. R. G., Ioannou, C. C., Morrell, L. J., Croft, D. P., Couzin, I. D., Waters, D. A., & Krause, J. (2008). Consensus decision making in human crowds. Animal behaviour, 75(2), 461-470. https://doi.org/10.1016/j.anbehav.2007.05.010

In groups of animals only a small proportion of individuals may possess particular information, such as a migration route or the direction to a resource. Individuals may differ in preferred direction resulting in conflicts of interest and, therefore,... Read More about Consensus decision making in human crowds.

A cost of leadership in human groups (2007)
Journal Article
Piyapong, C., Morrell, L. J., Croft, D. P., Dyer, J. R. G., Ioannou, C. C., & Krause, J. (2007). A cost of leadership in human groups. Ethology, 113(9), 821-824. https://doi.org/10.1111/j.1439-0310.2007.01382.x

Group living is the result of a dynamic trade-off between associated costs and benefits. However, these costs and benefits are not necessarily distributed equally across different spatial positions of groups which may result in different fitness retu... Read More about A cost of leadership in human groups.

Diet, familiarity and shoaling decisions in guppies (2007)
Journal Article
Morrell, L. J., Hunt, K. L., Croft, D. P., & Krause, J. (2007). Diet, familiarity and shoaling decisions in guppies. Animal behaviour, 74(2), 311-319. https://doi.org/10.1016/j.anbehav.2006.10.021

Animals are known to derive benefits from associating with familiar individuals, and familiarity is important in the structuring of animal groups. In fish, individuals are known to shoal preferentially with others they have previously spent time with... Read More about Diet, familiarity and shoaling decisions in guppies.

Why do female migratory birds arrive later than males? (2006)
Journal Article
Kokko, H., Gunnarsson, T. G., Morrell, L. J., & Gill, J. A. (2006). Why do female migratory birds arrive later than males?. The journal of animal ecology, 75(6), 1293-1303. https://doi.org/10.1111/j.1365-2656.2006.01151.x

1. In migratory birds males tend to arrive first on breeding grounds, except in sex-role reversed species. The two most common explanations are the rank advantage hypothesis, in which male-male competition for breeding sites drives stronger selection... Read More about Why do female migratory birds arrive later than males?.