Red squirrels mitigate costs of territory defence through social plasticity

Abstract

19For territorial species, the ability to be behaviourally plastic in response to changes in their social 20 environment may be beneficial by allowing individuals to mitigate conflict with conspecifics and 21 reduce the costs of territoriality. Here we investigated whether North American red squirrels 22 hoc analyses revealed that evidence of social plasticity in this system was primarily due to 32 within-individual changes in behaviour, which we were unable to estimate in the cross-sectional 33data. Our results demonstrate that red squirrels can reduce the costs of territoriality by 34 appropriately adjusting behaviour in response to changes in their social environment. However, 35our results also suggest that estimating plasticity by comparing behaviour among individuals (i.e. 36 cross-sectional analyses) may not always be reliable. Our ability to detect these effects may 37 therefore depend on having data with multiple observations from the same individuals across 38 different social environments. 39 40 Keywords 41 behavioural plasticity, behavioural time budgets, dear enemy, familiarity, red squirrel, social 42 competence, social environment, territoriality, vocalizations 43 44 individual's environment, since high levels of unpredictability are inherent when interacting with 63 other agents that can also exhibit plasticity in behaviour. Examples of social plasticity (changes 64 in behaviour in response to changing social conditions; Sih, Chang, & Wey, 2014;1 Montiglio,

Using a substitute species to inform translocation of an endangered territorial mammal

“…During the fall, the pressure exerted by the red squirrels present in the release area was intensified, where resident animals were exploring the enclosure and were making territorial calls from the top of the enclosure directly towards the translocated animals within the enclosure. This solitary territorial species benefits from having stable neighbours (72), at a point where animals avoid settlement in new empty middens even when they occupy poorer quality territories (73). For this reason, translocating single animals can cause the disruption of social relationship with territorial neighbours, which could have an impact on survival and behavior of translocated animals (74).…”

“…Red squirrels can maintain the same territory throughout their life, and consequently often choose territory sites close to familiar neighbours (63,65). Red squirrels with familiar neighbours reduced rates of territorial rattle calls and increased time spent in the nest (76). Therefore, considering the composition of the group to translocate can influence survival.…”

Familiar neighbours, but not relatives, enhance fitness in a territorial mammal

“…Following natal dispersal, individuals rarely relocate to a vacant territory (25), allowing for the establishment of 20 long-term familiarity among neighbouring individuals. Despite the fact that relationships with territory neighbours are primarily antagonistic, living near familiar neighbours provides important benefits for red squirrels, including reducing the risk of territory intrusion (26) and time spent on territory defence (27).…”

“…1, 2; Table 1). 5 We hypothesized that this large observed increase in siring success associated with social familiarity could result either from increased energetic resources (26,27) that allow male squirrels in familiar social neighbourhoods to travel farther to obtain mating opportunities (30,31), or that social familiarity might directly benefit males through increased mating success within their more familiar social neighbourhoods. Analysis of the spatial locations of male 10 paternity success revealed that males traveled farther to mate as familiarity with neighbours increased (β = 19.93 ± 8.83, t = 2.26, P =0.03; Fig.…”

“…3; Table S2). These results suggest that stable social relationships with neighbours increased the energy stores available to males, either through reduced territory defence (27) or reduced cache pilfering by neighbours (26), which allowed them to travel farther and increase their siring success (31).…”