Eastern water dragons use alternative social tactics at different local densities
Animals’ affiliative behaviour is, in many species, driven by population density. Although the causes of such an effect are probably varied, affiliative social behaviour can sometimes be used to minimise conflict and competition when conspecific density is high. However, individuals might instead use multiple different social tactics (e.g. social avoidance or social preference) in order to optimally minimise competition and social conflict at different local densities. Here, we investigated whether eastern water dragons (Intellegama lesueurii) use alternative social tactics at different local densities. Interestingly, we found that whilst the number of casual associations per individual increased linearly with density, as predicted by our null expectation, the relationship with density differed between social avoidance and social preference. In particular, individuals had more preferential associations at intermediate density but more avoidances at high density. This suggests that both male and female dragons use alternative social tactics according to the density of their social environment, possibly to optimally reduce social conflict.
This study investigated the relationship between local density and social tactics (e.g. social preference and social avoidance) in eastern water dragons. We demonstrate that dragons use different social tactics according to local density. We therefore present evidence that dragons may use alternative social tactics to optimally reduce competition and conflict in their local environment.
KeywordsDensity Social behaviour Eastern water dragons Social conflict Social tactics Competition
We would like to thank all staff at Roma St Parkland for their ongoing support and cooperation with data collection. We also thank all students and volunteers who have helped to collect data. Thanks also to two anonymous reviewers, as well as Damien Farine for constructive feedback and discussion on a previous version of this manuscript. This work was supported by Dr. Celine Frere’s USC Research Fellowship from University of the Sunshine Coast. This research was conducted with the approval of the University of the Sunshine Coast’s animal ethics committee (approval number AN/A/14/87).
Data generated and analysed during this study are included in this published article (and its supplementary information files). All R code used to generate null model can be found at (Strickland et al. 2017), and R code used to analyse and plot data is included in the supplementary material.
KS conceived the ideas with input from CF. KS and CF collected data. KS and EMP analysed data. KS wrote the manuscript, with input from all authors. All authors approved the final version of the manuscript for publication.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This work was supported by Dr. Celine Frere’s USC Research Fellowship from the University of the Sunshine Coast. Authors have no conflict of interest to declare. This research was conducted with the approval of the University of the Sunshine Coast’s animal ethics committee (approval number AN/A/14/87). All authors give consent for the publication of this article.
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