The effect of individual variation on the structure and function of interaction networks in harvester ants

Pinter‐Wollman, Noa; Wollman, Roy; Guetz, Adam; Holmes, Susan; Gordon, Deborah M.

doi:10.1098/rsif.2011.0059

Cited by 123 publications

(126 citation statements)

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“…In particular, theory and some empirical work suggest that highly connected [26] and socially influential [27,28] individuals might spread information quickly and thoroughly throughout their group. If this is true, and if information accuracy is important for group success, then the impacts of keystone individuals could change drastically depending on whether they possess accurate or inaccurate information.…”

Section: Introductionmentioning

confidence: 99%

The Achilles' heel hypothesis: misinformed keystone individuals impair collective learning and reduce group success

et al. 2016

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Many animal societies rely on highly influential keystone individuals for proper functioning. When information quality is important for group success, such keystone individuals have the potential to diminish group performance if they possess inaccurate information. Here, we test whether information quality (accurate or inaccurate) influences collective outcomes when keystone individuals are the first to acquire it. We trained keystone or generic individuals to attack or avoid novel stimuli and implanted these trained individuals within groups of naive colony-mates. We subsequently tracked how quickly groups learned about their environment in situations that matched (accurate information) or mismatched (inaccurate information) the training of the trained individual. We found that colonies with just one accurately informed individual were quicker to learn to attack a novel prey stimulus than colonies with no informed individuals. However, this effect was no more pronounced when the informed individual was a keystone individual. In contrast, keystones with inaccurate information had larger effects than generic individuals with identical information: groups containing keystones with inaccurate information took longer to learn to attack/avoid prey/predator stimuli and gained less weight than groups harbouring generic individuals with identical information. Our results convey that misinformed keystone individuals can become points of vulnerability for their societies.

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Section: Introductionmentioning

confidence: 99%

The Achilles' heel hypothesis: misinformed keystone individuals impair collective learning and reduce group success

et al. 2016

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“…The ideal gas model predicts encounter rates assuming random movement at a constant speed while taking the local population density, detection distance and group spread into account (Hutchinson & Waser, 2007). These empirical studies and the ideal gas model suggest that individuals that share space interact more frequently if they are moving more (Pinter-Wollman, Wollman, Guetz, Holmes, & Gordon, 2011). For the lizards in our study, the higher network density and network stability in the more complex habitats could simply result from a general increase in interaction frequencies, as well as repeated interactions among neighbouring individuals across time, owing to the greater distances moved by individuals when mazes were present.…”

Section: Effect On Weekly Binary Network Structurementioning

confidence: 99%

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

et al. 2016

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Social structure is a fundamental component of a population that drives ecological and evolutionary processes ranging from parasite transmission to sexual selection. Nevertheless, we have much to learn about factors that explain variation in social structure. We used advances in biologging and social network analysis to experimentally test how the local habitat, and specifically habitat complexity, modulates social structure at different levels in wild populations. Sleepy lizards, Tiliqua rugosa, establish nonrandom social networks that are characterized by avoidance of some neighbours and frequent interactions with one opposite-sex individual. Using synchronous GPS locations of all adult lizards, we constructed social networks based on spatial proximity of individuals. We increased habitat structural complexity in two study populations by adding 100 short fences across the landscape. We then compared the resulting movement behaviour and social structure between these populations and two unmanipulated populations. Social connectivity (network density) and social stability, measured at weekly intervals, were greater in populations with increased habitat structural complexity. The level of agonistic interaction (quantified as scale damage) was also higher, indicating a fitness cost of greater social connectivity. However, some network parameters were unaffected by increased complexity, including disassortative mixing by sex, and at the individual level, social differentiation among associates (coefficient of variation of edge weights) and maximal interaction frequencies (maximal edge weight). This suggests divergent effects of changed ecological conditions on individual association behaviour compared to the resulting social structure of the population. Our results contrast with those from studies of more gregarious species, in which higher structural complexity in the environment relaxed the social connectivity. This shows that the response to altered ecological conditions can differ fundamentally between species or between populations, and we suggest that it depends on their tendency for gregarious behaviour.

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“…This finding may have resulted from bold fish shoaling in slightly smaller groups than shy individuals and thereby having fewer opportunities to switch partners (assuming shifts in group membership occurred at a relatively lower rate). As interaction frequency can determine how rapidly information spreads through a group (Pinter-Wollman et al, 2011), such shoaling dynamics plausibly contributed to the comparatively weak social transmission effect in bold-dominated groups; i.e., uninformed individuals may have been less likely to come into contact with knowledgeable group mates. On the other hand, such an effect could also lower an individual's risk of infection by reducing the likelihood of associating with infected conspecifics (Drewe & Perkins, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…Social network analysis has offered novel insights into the fine-scale structure of animal populations, the potential drivers of that structure (Sundaresan et al, 2007;Morrell et al, 2008;Aplin et al, 2013), and its consequences for social processes, such as cooperation (Croft et al, 2006), information flow (Pinter-Wollman et al, 2011;Aplin et al, 2012), disease transmission (Cross et al, 2004;VanderWaal, Atwill, et al, 2014) and sexual selection (Oh & Badyaev, 2010). However, a frequent criticism of animal social network studies is that they are primarily descriptive without providing critical tests regarding either the mechanisms which generated the observed patterns, or the functional consequences of network structure Wilson et al, 2014).…”

Section: Chapter II Interludementioning

confidence: 99%

“…Such structural shifts in response to the threat of predation can have important implications for a number of social processes. For example, stable social ties can facilitate the maintenance of cooperative relationships (Croft et al, 2006;Micheletta et al, 2012), while high network density is associated with the rapid diffusion of information through a group (Voelkl & Noë, 2010;Pinter-Wollman et al, 2011). In species exhibiting fission-fusion behavior, the social dynamics from which network structures emerge are also expected to vary according to ambient levels of risk, given their predicted effects on individual exposure to predation (Krause et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Social dynamics, network structure, and information diffusion in fish shoals.

Hasenjager¹

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for always ensuring my library was well-stocked, and for fostering my enduring love of the natural world. Animal populations are often highly structured, with individuals differing in terms of whom they interact with and how frequently they do so. The resulting pattern of relationships constitutes a population's social network. In this dissertation, I examine how environmental variation can shape social networks and influence information flow within them. In Chapter I, I review the history of social network analysis in animal behavior research, and discuss recent insights generated by network approaches in behavioral ecology. I focus on the fields of: social learning, collective behavior, animal personalities, and cooperation. Animal network studies are often criticized for a lack of replication at the network level and an over-reliance on descriptive approaches in lieu of hypothesis testing. Small, shoaling fish may provide a means to address these concerns, as manipulative experiments can be conducted on replicate social groups under captive conditions. Chapters III-V examine the impacts of environmental variation on the social networks of Trinidadian guppy (Poecilia reticulata) shoals, the social dynamics from which they emerge, and information diffusion within them. In the experiments described in Chapter III, I manipulated shoal composition in terms of within-group familiarity.Mixed shoals of familiar and unfamiliar fish exhibited greater homogeneity in network vi structure relative to other groups, which likely contributed to the rapid diffusion of foraging information observed within them. In the experiments discussed in Chapter IV, Imanipulated the within-shoal mixture of personality types. In addition to impacting frequencies of partner switching and patterns of phenotypic assortment, individual-and group-level personality variation had strong effects on the initial acquisition of novel foraging information and the speed of its transmission through a group. In the experiments in Chapter V, I manipulated the ambient predation risk perceived by groups.High-risk conditions were associated with shifts in network structure consistent with attempts to minimize predation risk. High ambient risk also impeded the acquisition and subsequent transmission of foraging information, likely due to heightened neophobia and/or an increase in the perceived costs of personal sampling. I conclude in Chapter VI by considering the broader implications of my work and highlighting promising avenues for future research.vii

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The effect of individual variation on the structure and function of interaction networks in harvester ants

Cited by 123 publications

References 71 publications

The Achilles' heel hypothesis: misinformed keystone individuals impair collective learning and reduce group success

The Achilles' heel hypothesis: misinformed keystone individuals impair collective learning and reduce group success

Environment modulates population social structure: experimental evidence from replicated social networks of wild lizards

Social dynamics, network structure, and information diffusion in fish shoals.

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