Meerkat latrines : cooperation, competition and discrimination

[摘要] ENGLISH ABSTRACT: Many territorial carnivores deposit faeces and other scent-marks at specific latrinesites, and their role in territorial defence is often assumed. However, recent empiricaland theoretical work suggests that ultimate explanations of territoriality differbetween the sexes. In this thesis, I investigate patterns of latrine-use in cooperativelybreeding meerkats, Suricata suricatta. Meerkats exhibit high reproductive skew, andin such societies an individual's optimal investment in territory defence and intruderdeterrence will depend not only on its sex, but also its breeding status within thegroup. The spatial and temporal distribution of meerkat latrines reflects the diversityin intruder type. Shared latrine sites between neighbouring groups facilitate costeffectivemonitoring of predictable intruders and surrounding land tenure. In contrast,intruding transient groups and prospecting males are effectively intercepted bylatrines concentrated in the core of the territories, close to refuges. This represents theoptimal strategy, as meerkat territories are too large to allow effective scent-markingaround their entire peripheries, and these intruders travel between refuges duringintrusions. Temporal patterns of latrine-use suggest their importance in mate-defence.Latrine-use was correlated with encounters with prospecting males and oestrousperiods of resident females, and reached a peak coinciding with the season of elevateddispersal and take-over events. Additionally, rather than cooperatively contributing toterritorial defence, individuals participated selfishly at latrines. Males preferentiallyover-marked female scent-marks and scent-marked at significantly greater rates thanfemales, which resulted in male-biased latrines that were unrepresentative of groupcomposition. Although all individuals investigated female scent-marks forsignificantly longer than male scent-marks, females invested most, suggesting thatintra-group monitoring is an important aspect of latrine visits for females. The deleterious effects of close inbreeding are well known, but regular dispersal in bothsexes, and long dominance tenure, result in unfamiliar siblings having a highprobability of encountering one another post-dispersal. As latrines are implicated inmate-defence, olfactory assessment of factors affecting mating decisions might beexpected, but although individuals do recognise foreign faeces, discrimination doesnot appear to occur on the basis of kinship. Together, these findings have broadimplications for our understanding of individual variation and sex differences inscent-marking behaviour and territoriality.

[发布机构] Stellenbosch University