Deciding when to intrude on a neighbour: quantifying behavioural mechanisms for temporary territory expansion

Abstract

Flexible territorial structures are common to a variety of animal populations. When resources are abundant, animals can maintain relatively fixed territory boundaries. However, if resources decline, animals may have to intrude temporarily into a neighbour's territory to secure enough food for survival. Although such intrusions may be necessary, they take time away from foraging and can lead to costly conflicts, resulting in a behavioural trade-off. Here, we examine this trade-off using a spatially explicit, energy-based movement model inspired by observations of giant otters. We uncover conditions under which temporary neighbour intrusions are beneficial. We show that, under certain circumstances, this benefit is sufficient for allowing territorial groups to survive in perpetuity, when otherwise they would be forced to disperse or die. Our model also reveals plausible mechanisms behind a variety of observed phenomena, including the emergence of intermediate-sized territorial groups, territorial fission/fusion dynamics, and the employment of multiple methods for advertising territories (e.g. vocal and olfactory). Although we focus our modelling on giant otters, the behavioural mechanisms it describes are quite general, having been observed across a wide range of taxa, including birds, fish and mammals. Our model therefore serves as a general theoretical test-bed for understanding temporary territory expansion.

A mechanistic, stigmergy model of territory formation in solitary animals: Territorial behavior can dampen disease prevalence but increase persistence

“…Ultimately, stigmergy is just one possible mechanism for informing territorial-like movement behavior. It is likely that many species respond to cues in real time (e.g., visual cues, vocalization) in addition to transient environmental cues (e.g., [11]). Another important question is understanding how temporal switches in the valence of the stigmergy cues might affect pathogen transmission.…”

“…Mechanistic models of home range formation have their roots in a spatially-biased random walk process [7]. These models have evolved to incorporate underlying resource availability and selection, population dynamics, and territorial behaviors such as scent marking that lead to dynamic home range formation [8][9][10][11][12][13] resulting in individual interactions. Even so, disease ecology has yet to universally account for contact behavior that is driven explicitly by individual movement patterns [4,5,14].…”

A mechanistic, stigmergy model of territory formation in asocial animals: Territorial behavior can dampen disease prevalence but increase persistence

“…Ultimately, stigmergy is just one possible mechanism for informing territorial-like movement behavior. It is likely that many species respond to cues in real time (e.g., visual cues, vocalization) in addition to transient environmental cues (e.g., [37]). Another important question is understanding how temporal switches in the valence of the stigmergy cues might affect disease transmission.…”

Transient disease dynamics across ecological scales

“…A host's UD may equilibrate slowly, if at all (Fryxell et al 2008;Potts and Lewis 2016). It may also be sensitive to local conditions, such as terrain (Moorcroft et al 2006), resource availability (Moorcroft et al 2006;Bateman et al 2015), and the presence of conspecifics or predators (Lewis and Moorcroft 2001;Bateman et al 2015;Tao et al 2016;Potts et al 2018). The transitional UDs may be highly variable and create short-term opportunities for host-pathogen contacts that impact population, metapopulation, and community level transmissions (Plowright et al 2011;Ramsey et al 2014;White et al 2020).…”