Characterizing the Collective Personality of Ant Societies: Aggressive Colonies Do Not Abandon Their Home

Animal groups can show consistent behaviors or personalities just like solitary animals. We studied the collective behavior of Temnothorax nylanderi ant colonies, including consistency in behavior and correlations between different behavioral traits. We focused on four collective behaviors (aggression against intruders, nest relocation, removal of infected corpses and nest reconstruction) and also tested for links to the immune defense level of a colony and a fitness component (per-capita productivity). Behaviors leading to an increased exposure of ants to micro-parasites were expected to be positively associated with immune defense measures and indeed colonies that often relocated to other nest sites showed increased immune defense levels. Besides, colonies that responded with low aggression to intruders or failed to remove infected corpses, showed a higher likelihood to move to a new nest site. This resembles the trade-off between aggression and relocation often observed in solitary animals. Finally, one of the behaviors, nest reconstruction, was positively linked to per-capita productivity, whereas other colony-level behaviors, such as aggression against intruders, showed no association, albeit all behaviors were expected to be important for fitness under field conditions. In summary, our study shows that ant societies exhibit complex personalities that can be associated to the physiology and fitness of the colony. Some of these behaviors are linked in suites of correlated behaviors, similar to personalities of solitary animals

Extreme behavioural shifts by baboons exploiting risky, resource-rich, human-modified environments

Abstract A range of species exploit anthropogenic food resources in behaviour known as ‘raiding’. Such behavioural flexibility is considered a central component of a species’ ability to cope with human-induced environmental changes. Here, we study the behavioural processes by which raiding male chacma baboons (Papio ursinus) exploit the opportunities and mitigate the risks presented by raiding in the suburbs of Cape Town, South Africa. Ecological sampling and interviews conducted with ‘rangers’ (employed to manage the baboons’ space use) revealed that baboons are at risk of being herded out of urban spaces that contain high-energy anthropogenic food sources. Baboon-attached motion/GPS tracking collars showed that raiding male baboons spent almost all of their time at the urban edge, engaging in short, high-activity forays into the urban space. Moreover, activity levels were increased where the likelihood of deterrence by rangers was greater. Overall, these raiding baboons display a time-activity balance that is drastically altered in comparison to individuals living in more remote regions. We suggest our methods can be used to obtain precise estimates of management impact for this and other species in conflict with people

Weaving animal temperament into food webs: implications for biodiversity

Moran N, Wong BBM, Thompson RM. Weaving animal temperament into food webs: implications for biodiversity. Oikos. 2017;126(7):917-930.Recent studies into community level dynamics are revealing processes and patterns that underpin the biodiversity and complexity of natural ecosystems. Theoretical food webs have suggested that species‐rich and highly complex communities are inherently unstable, but incorporating certain characteristics of empirical communities, such as allometric body size scaling and non‐random interaction distributions, have been shown to enhance stability and facilitate species coexistence. Incorporating individual level traits and variability into food web theory is seen as a future pathway for this research and our growing knowledge of individual behaviours, in the form of temperament (or personality) traits, can inform the direction of this research. Temperament traits are consistent differences in behaviour between individuals, which are repeatable across time and/or across ecological contexts, such as aggressive or boldness behaviours that commonly differ between individuals of the same species. These traits, under the framework of behavioural reaction norms, show both individual consistency as well as contextual and phenotypic plasticity. This is likely to contribute significantly to the effects of individual trait variability and adaptive trophic behaviour on the structure and dynamics of food webs, which are apparently stabilizing. Exploring the role of temperament in the context of community ecology is a unique opportunity for cross‐pollination between ecological fields, and can provide new insights into community stability and biodiversity

Emergence of Leadership within a Homogeneous Group

All the authors thank Byron Crouch for his work on performing exploratory simulations of the model. Some of the computing for this project was performed at the OU Supercomputing Center for Education & Research (OSCER) at the University of Oklahoma.Large scale coordination without dominant, consistent leadership is frequent in nature. How individuals emerge from within the group as leaders, however transitory this position may be, has become an increasingly common question asked. This question is further complicated by the fact that in many of these aggregations, differences between individuals are minor and the group is largely considered to be homogeneous. In the simulations presented here, we investigate the emergence of leadership in the extreme situation in which all individuals are initially identical. Using a mathematical model developed using observations of natural systems, we show that the addition of a simple concept of leadership tendencies which is inspired by observations of natural systems and is affected by experience can produce distinct leaders and followers using a nonlinear feedback loop. Most importantly, our results show that small differences in experience can promote the rapid emergence of stable roles for leaders and followers. Our findings have implications for our understanding of adaptive behaviors in initially homogeneous groups, the role experience can play in shaping leadership tendencies, and the use of self-assessment in adapting behavior and, ultimately, self-role-assignment.Yeshttp://www.plosone.org/static/editorial#pee

The influence of individual and colony level variation in behavior on colony performance in ants

In my dissertation I investigated the influence of behavioral variation between and within ant colonies on group performance. In particular, I analyzed how evolution shapes behavior in response to ecological conditions, and whether within-group diversity improves productivity as suggested by theory. Our field and laboratory experiments showed that behavioral diverse groups are more productive. Different aggression levels within colonies were beneficial under competitive field situations, whereas diversity in brood care and exploratory behavior were favored in non-competitive laboratory situations. We then examined whether population density and social parasite presence shape aggression through phenotypic plasticity and/or natural selection. The importance of selection was indicated by the absence of density or parasite effects on aggression in a field manipulation. Indeed, more aggressive colonies fared better under high density and during parasite attack. When analyzing the proximate causes of individual behavioral variation, ovarian development was shown to be linked to division of labor and aggressiveness. Finally, our studies show that differences in the collective behavior can be linked to immune defense and productivity. My dissertation demonstrates that behavioral variation should be studied on multiple scales and when possible combined with physiological analyses to better understand the evolution of animal personalities in social groups.rnIn meiner Dissertation untersuchte ich den Einfluss von Verhaltensvariabilität zwischen und innerhalb von Ameisenkolonien auf ihre Produktivität. Hierbei analysierte ich wie sich im Laufe der Evolution das Verhalten an ökologische Bedingungen anpasst, und ob Diversität im Verhalten innerhalb einer Kolonie die Produktivität erhöht, wie es theoretische Modelle vorhersagen. Unsere Freiland- und Laborexperimente zeigten, dass Kolonien mit höherer Diversität tatsächlich produktiver waren. Kolonien mit unterschiedlich aggressiven Tieren hatten einen Vorteil in einer kompetitiven Freilandsituation, während Variabilität im Brutfürsorge- und Explorationsverhalten unter nicht-kompetitiven Laborbedingungen förderlich waren. Als Nächstes untersuchten wir, ob die Populationsdichte oder die Präsenz von Sozialparasiten durch phänotypische Plastizität und/oder natürliche Selektion einen Einfluss auf die Aggression hat. Selektion stellte sich als wichtiger heraus, da sich die Kolonien durch Manipulation von Dichte und Sozialparasiten im Freiland nicht in ihrer Aggression verändern ließen. In der Tat kamen aggressive Kolonien besser mit hoher Dichte und der Invasion von Parasiten zurecht. Die Analyse der proximaten Ursachen individueller Verhaltensunterschiede ergab, dass die Ovarienentwicklung mit der Arbeitsteilung und der Aggression zusammenhängt. Schließlich zeigen unsere Studien auf Kolonieniveau, dass auch Unterschiede in kollektiven Verhaltensweisen zwischen Kolonien mit der Produktivität und interessanterweise auch mit der Immunabwehr zusammenhängen. Demzufolge sollte für ein tieferes Verständnis für die Evolution von Persönlichkeitsmerkmalen bei Tieren in sozialen Gruppen, Verhaltensvariation auf mehreren Ebenen untersucht, und wenn möglich mit physiologischen Analysen kombiniert werden.rn116 S

The influence of individual and colony level variation in behavior on colony performance in ants

In my dissertation I investigated the influence of behavioral variation between and within ant colonies on group performance. In particular, I analyzed how evolution shapes behavior in response to ecological conditions, and whether within-group diversity improves productivity as suggested by theory. Our field and laboratory experiments showed that behavioral diverse groups are more productive. Different aggression levels within colonies were beneficial under competitive field situations, whereas diversity in brood care and exploratory behavior were favored in non-competitive laboratory situations. We then examined whether population density and social parasite presence shape aggression through phenotypic plasticity and/or natural selection. The importance of selection was indicated by the absence of density or parasite effects on aggression in a field manipulation. Indeed, more aggressive colonies fared better under high density and during parasite attack. When analyzing the proximate causes of individual behavioral variation, ovarian development was shown to be linked to division of labor and aggressiveness. Finally, our studies show that differences in the collective behavior can be linked to immune defense and productivity. My dissertation demonstrates that behavioral variation should be studied on multiple scales and when possible combined with physiological analyses to better understand the evolution of animal personalities in social groups.rnIn meiner Dissertation untersuchte ich den Einfluss von Verhaltensvariabilität zwischen und innerhalb von Ameisenkolonien auf ihre Produktivität. Hierbei analysierte ich wie sich im Laufe der Evolution das Verhalten an ökologische Bedingungen anpasst, und ob Diversität im Verhalten innerhalb einer Kolonie die Produktivität erhöht, wie es theoretische Modelle vorhersagen. Unsere Freiland- und Laborexperimente zeigten, dass Kolonien mit höherer Diversität tatsächlich produktiver waren. Kolonien mit unterschiedlich aggressiven Tieren hatten einen Vorteil in einer kompetitiven Freilandsituation, während Variabilität im Brutfürsorge- und Explorationsverhalten unter nicht-kompetitiven Laborbedingungen förderlich waren. Als Nächstes untersuchten wir, ob die Populationsdichte oder die Präsenz von Sozialparasiten durch phänotypische Plastizität und/oder natürliche Selektion einen Einfluss auf die Aggression hat. Selektion stellte sich als wichtiger heraus, da sich die Kolonien durch Manipulation von Dichte und Sozialparasiten im Freiland nicht in ihrer Aggression verändern ließen. In der Tat kamen aggressive Kolonien besser mit hoher Dichte und der Invasion von Parasiten zurecht. Die Analyse der proximaten Ursachen individueller Verhaltensunterschiede ergab, dass die Ovarienentwicklung mit der Arbeitsteilung und der Aggression zusammenhängt. Schließlich zeigen unsere Studien auf Kolonieniveau, dass auch Unterschiede in kollektiven Verhaltensweisen zwischen Kolonien mit der Produktivität und interessanterweise auch mit der Immunabwehr zusammenhängen. Demzufolge sollte für ein tieferes Verständnis für die Evolution von Persönlichkeitsmerkmalen bei Tieren in sozialen Gruppen, Verhaltensvariation auf mehreren Ebenen untersucht, und wenn möglich mit physiologischen Analysen kombiniert werden.r

Data from: Animal personality in a foundation species drives community divergence and collapse in the wild

1. Despite thousands of papers on the topic, precious few of the studies on animal personality have considered the role of personality in shaping community-level processes. Here, we test the effect of individual variation on the long-term trajectories of biological communities, from initiation to their demise. The spider Anelosimus studiosus builds webs that serve as habitat for >50 species of spider, which together construct a species-rich silken reef. This species also exhibits a temporally consistent behavioural polymorphism where females exhibit either an aggressive or docile phenotype (personality). 2. In this study, we established incipient colonies of either two docile or two aggressive females and then tracked community succession and persistence over 7 years in the field. In particular, we noted the community compositions associated with colony extinction/collapse events, which are common in this species. 3. The community composition of webs founded by different phenotypes diverged rapidly in their early successional stages. However, this period of divergence was ephemeral and all communities eventually converged on a similar composition; communities founded by aggressive females merely took longer to reach it. This secondary stage of community convergence was itself short-lived and independent of founders' personality; all communities collapsed within a year of achieving it. 4. Experimentally imposing this fatal climax composition on colonies caused 80% of communities to collapse within a year, suggesting that this climax composition actually causes the collapse of the community. Community collapse was characterized by a complete die-off of the foundation species and the dispersal of all other spiders. Thus, the behavioural traits of the founding, foundational individuals of these communities dictate their path of succession and longevity in the wild