Search results for "Group living"

Social interactions modulate the virulence of avian malaria infection

2013

There is an increasing understanding of the context-dependent nature of parasite virulence. Variation in parasite virulence can occur when infected individuals compete with conspecifics that vary in infection status; virulence may be higher when competing with uninfected competitors. In vertebrates with social hierarchies, we propose that these competition-mediated costs of infection may also vary with social status. Dominant individuals have greater competitive ability than competing subordinates, and consequently may pay a lower prevalence-mediated cost of infection. In this study we investigated whether costs of malarial infection were affected by the occurrence of the parasite in compet…

Food availability and competition do not modulate the costs of Plasmodium infection in dominant male canaries.

2013

7 pages; International audience; Understanding the different factors that may influence parasite virulence is of fundamental interest to ecologists and evolutionary biologists. It has recently been demonstrated that parasite virulence may occur partly through manipulation of host competitive ability. Differences in competitive ability associated with the social status (dominant or subordinate) of a host may determine the extent of this competition-mediated parasite virulence. We proposed that differences between subordinate and dominant birds in the physiological costs of infection may change depending on the level of competition in social groups. We observed flocks of domestic canaries to …

Asymmetrical interspecific communication of predatory threat in mixed-species colonies of lesser kestrels (Falco naumanni) and jackdaws (Corvus moned…

2019

Sympatric species derive benefits by attending to information conveyed by heterospecifics. Our previous finding of reduced vigilance among jackdaws and lesser kestrels residing in mixed-species colonies suggested a reliance on interspecific communication of information regarding predatory threats. To test for interspecific communication of threat, we first determined whether jackdaw and lesser kestrel call structure varied with perceived threat. In this call production phase of our study, free-living birds in mixed-species colonies were presented with models representing a potential nest predator (European magpie) or with non-threatening stimuli (wood pigeon or wooden dowel) in proximity to…

Shoaling with infected conspecifics does not improve resistance to trematode infection

2018

Group‐living animals can gain protection against parasitic infections through social contacts with previously infected conspecifics (social immunization). Recent research suggests that such protective effects can be induced through visual or chemical cues released by infected individuals, resulting in anticipatory immune upregulation among group members. Here, we study cue‐induced social resistance in rainbow trout Oncorhynchus mykiss exposed to a trematode parasite, the eye‐fluke Diplostomum pseudospathaceum. We established groups of naïve individuals (receivers) that were paired with previously infected individuals (donors) at different ratios of donors to receivers and at different time …

Null models for animal social network analysis and data collected via focal sampling: Pre‐network or node network permutation?

2020

In social networks analysis, two different approaches have predominated in creating null models for hypothesis testing, namely pre‐network and node network permutation approaches. Although the pre‐network permutation approach appears more advantageous, its use has mainly been restricted to data on associations and sampling methods such as ‘group follows’. The pre‐network permutation approach has recently been adapted to data on interactions and the focal sampling method, but its performance in different scenarios has not been thoroughly explored. Here, we assessed the performance of the pre‐network and node network permutation approach in several simulated scenarios based on proneness to fa…

Health situation and related social conditions among 66-year-old Finnish men.

1976

Health situation and related social conditions among 66-year-old Finnish men. Heikkinen, E., Käyhty-Seppänen, B. and Pohjolainen, P. (Dept. of Public Health, University of jyväskylä, Finland). The aims of the study were to reveal the extent of physical activity, nutritional habits, smoking and alcohol consumption and the relation of these to previous occupation among recently retired men. The number of men belonging to various health risk groups was estimated on the basis of the results. About 10% had inadequate nutritional habits as judged from their food expenses and number of daily hot meals and about 20% practised physical exercise in the way which is considered necessary for the impro…

Social immunity and the evolution of group living in insects

2015

The evolution of group living requires that individuals limit the inherent risks of parasite infection. To this end, group living insects have developed a unique capability of mounting collective anti-parasite defences, such as allogrooming and corpse removal from the nest. Over the last 20 years, this phenomenon (called social immunity) was mostly studied in eusocial insects, with results emphasizing its importance in derived social systems. However, the role of social immunity in the early evolution of group living remains unclear. Here, I investigate this topic by first presenting the definitions of social immunity and discussing their applications across social systems. I then provide a…

Mechanisms of reciprocity and diversity in social networks: a modeling and comparative approach

2018

Individual-based computer models show that different mechanisms, proximity-based or emotional bookkeeping, can lead to reciprocation. By comparing social networks from different computer models with those of empirical data, we show that the models’ social networks bear limited resemblance with some features of the observed social networks. This indicates that additional social processes (third-party awareness) may be needed in these models to represent more accurately the social behavior and interaction patterns observed in group-living animals.

Asymmetrical interspecific communication in avian mixed species colonies

Sympatric species derive benefits by attending to information conveyed by heterospecifics. We previously reported reduced vigilance among jackdaws (Corvus monedula) and lesser kestrels (Falco numanni) residing in mixed species colonies and conducted the present study to test for interspecific communication of threat associated with European magpies (Pica pica) as nest predators. After quantifying structural differences in jackdaw and lesser kestrel calls relative to European magpie versus non-predator models, we played back calls of jackdaws and lesser kestrels representative of the different model types to test whether receivers perceive threat-related variation in either conspecific or he…

Diseased Social Predators

2017

Social predators benefit from cooperation in the form of increased hunting success, but may be at higher risk of disease infection due to living in groups. Here, we use mathematical modeling to investigate the impact of disease transmission on the population dynamics benefits provided by group hunting. We consider a predator-prey model with foraging facilitation that can induce strong Allee effects in the predators. We extend this model by an infectious disease spreading horizontally and vertically in the predator population. The model is a system of three nonlinear differential equations. We analyze the equilibrium points and their stability as well as one- and two-parameter bifurcations. …