Rival group scent induces changes in dwarf mongoose immediate behavior and subsequent movement

Abstract

In many social species, groups of animals defend a shared territory against rival conspecifics. Intruders can be detected from a variety of cues, including faecal deposits, and the strength of response is expected to vary depending on the identity of the rival group. Previous studies examining differences in response to neighbour and stranger groups have focused on the immediate response to the relevant cues. Here, we investigated how simulated intrusions of rival groups affect both immediate responses and post-inspection movement patterns. To do so, we used a faecal translocation experiment at latrine sites within the territories of dwarf mongoose Helogale parvula groups. Immediate responses were adjusted to the level of threat, with greater scentmarking behaviour, time spent at the latrine and group-member participation when groups were presented with faecal matter from out-group rivals relative to control (own-group and herbivore) faeces. Subsequent movement of the group was also affected by threat level, with a decrease in speed and distance covered following simulated intrusions by out-group rivals compared to control conditions. However, there were no significant differences in immediate responses or post-latrine movement patterns when comparing simulated neighbour and stranger intrusions. These results indicate that territorial intrusions can elicit not just an immediate change in behaviour but more farreaching consequences in terms of movement dynamics. They also raise the possibility that neighbour-stranger discrimination predictions are not necessarily as clear-cut as previously described.

Spontaneous discrimination of urine odours in wild African lions, Panthera leo

“…For resident female lions, rival females (and their prides) pose a significant territorial threat (Schaller, 1972;Packer et al, 1990). Since mammalian scent-marking often functions for territory demarcation Gosling, 2001, Christensen, Kern, Bennitt andRadford, 2016), it would be adaptive for females to pay attention to the scent-marks of territory rivals (non-residents) to detect when their territory ownership is being challenged. While we provide evidence that female lions could use urine to determine the residency status of conspecifics, further research would be required to sufficiently test this in males.…”

Causes and consequences of inverse density‐dependent territorial behaviour and aggression in a monogamous mammal

“…Few studies, however, examine spatial responses towards intruder scents, for example, the patrolling patterns of respondents. For example, dwarf mongooses (Helogale parvula) moved shorter distances after a simulated intrusion, possibly due to increased vigilance behaviour (Christensen, Kern, Bennitt, & Radford, 2016), and male red foxes (Vulpes vulpes) spent more time patrolling in areas with artificial scent marks, suggesting an increased effort to defend their territory (Arnold, Soulsbury, & Harris, 2011). Further, little is known about how external factors, such as population density, affect the frequency of territory intrusions (but see Dantzer, Boutin, Humphries, & McAdam, 2012) and consequently patrolling responses by territory owners and mate change patterns via forced divorce (the replacement of one pair member by an intruder, Lardy, Cohas, Figueroa, & Allainé, 2011;Taborsky & Taborsky, 1999).…”

Expanding the Link between Out-Group Threats and In-Group Behavior: (A Reply to Kavaliers and Choleris)

“…As Kavaliers and Choleris (In press) point out, pathogen exposure and the risk of infection may represent an additional threat posed by outsiders. Stronger immediate responses might be expected to infected as opposed to healthy outsiders, in the same way that there are stronger responses to individuals or groups who represent a greater threat in other contexts -for example, differences in the relative threat posed by groups of different size (Radford and du Plessis 2004) and by neighbours and strangers (Radford 2005;Müller and Manser 2007) have been shown to be important -with knock-on consequences for in-group behaviour (Radford 2008b;Bruintjes et al 2016;Christensen et al 2016). Moreover, exposure to pathogens can influence the response to subsequent out-group threats; pathogen 'priming' can lead to more negative reactions towards outsiders (Navarette and Fessler 2006;Fincher et al 2011).…”

“…During such encounters, there may be the opportunity to assess the pathogen threat presented by outsiders. However, in-group behaviour can also be influenced by indirect cues to the recent presence of rivals; for example, when encountering urine or faecal deposits (Christensen et al 2016). There is also some evidence that spending time in territorial areas where conflicts with rivals are most likely can lead to in-group behavioural responses similar to those seen following actual conflicts (Radford 2011).…”

“…Changes in the way group members behave towards one another can occur during the conflict itself; this is the timeframe considered by most human studies using economic games (West et al 2006;Puurtinen and Mappes 2009). The majority of the empirical work on non-human animals has focussed on the immediate aftermath of conflicts with rivals , demonstrating changes in affiliation or aggression between group members, and alterations in movement patterns (Radford 2008a, b;Polizzi di Sorrentino 2012;Crofoot 2013;Christensen et al 2016). There is also the possibility of longer-lasting behavioural effects; recent work on a cooperatively breeding bird species has shown out-group conflicts can influence roost choice, consensus decision-making and group cohesion many hours later (Radford and Fawcett 2014).…”