Play fighting social networks do not predict injuries from later aggression

Abstract

Early play fighting mimics later aggression in many species, and may, therefore, be expected to reduce costs from later aggressive interactions. Using social network analysis (SNA) the effect of a central play fighting network position on later skin lesions from aggression was assessed in domestic pigs. Piglets (n = 263) were kept in litter groups or socialised pre-weaning with another litter to enhance play fighting experience. Play fighting was recorded for 1.5 h per day over 6 days pre-weaning. Play fighting network centrality was quantified using measures of individual network position and entire network structure (degree, eigenvector, betweenness, clustering coefficient). Skin lesions from aggression were counted after a dyadic contest and at 24 h and 3 weeks following group mixing. Pigs with play fighting interactions with many partners experienced fewer lesions from the dyadic contest (in-degree, p = 0.01) and tended to received fewer lesions 3 weeks after group mixing (degree, p = 0.088) but no other play fighting centrality measures affected the number of lesions at any point. The benefits of play fighting were therefore limited to specific aggressive social contexts. The tendency of socialised piglets to play fight with non-littermates did not affect subsequent lesions. We advocate the use of SNA over approaches that only consider dyadic interactions to further our understanding of the influence of early social group interactions on later life experience.

Measuring Play Fighting in Rats: A Multilayered Approach

“…In pigs, which are normally reared in a litter, there are partner preferences, leading to some members playing together more than others (Turner et al., 2020); even in species that typically give birth to one infant at a time but live in social groups, there are many potential partners, and not all of them are selected equally (Lilley, Ham, & Hill, 2020; Shimada & Sueur, 2018). An experimental manipulation of rats may have a minimal effect on the play recorded in the dyadic test, but it may have a major impact on partner selection.…”

Who Plays With Whom: Farrowing Environment Influences Isolation of Foster Piglets in Play

“…The total number of play invitations received and initiated for a given node (piglet). (Wey et al, 2008;Canon Jones et al, 2010;Turner et al, 2020) they remain equally good connectors within the network. This finding suggests that all foster piglets are interacting with the majority of non-foster piglets in the Pen neonatal environment, rather than the suggestion of segregation between foster and non-foster piglets which appears to be the case in Crates at weeks 1 and 2.…”

“…High betweenness centrality indicates that the piglet connected a number of otherwise unconnected piglets. (Wey et al, 2008;Turner et al, 2020) In degree centrality…”

“…More specifically we wanted to understand more about the sociality of piglet play and cohesion throughout the litter pre-weaning. Over recent years, the application of social network analyses has gained significant traction for animal behaviour and welfare science due to it providing a powerful tool for strengthening our understanding of the likely causes and consequences of animal sociality (Wey et al, 2008;Turner et al, 2020). It offers the ability to consider the connections beyond the dyadic level, extending to an animals' indirect social connections or "friends of friends" (Wey et al, 2008;Foister et al, 2018;Turner et al, 2020).…”

“…Over recent years, the application of social network analyses has gained significant traction for animal behaviour and welfare science due to it providing a powerful tool for strengthening our understanding of the likely causes and consequences of animal sociality (Wey et al, 2008;Turner et al, 2020). It offers the ability to consider the connections beyond the dyadic level, extending to an animals' indirect social connections or "friends of friends" (Wey et al, 2008;Foister et al, 2018;Turner et al, 2020). This has had important welfare implications across a range of species including pigs, where, for example it has been used for predicting chronic aggression in commercial pig systems (Foister et al, 2018).…”