Ranging Behavior and Possible Correlates of Pair-Living in Southeastern Avahis (Madagascar)

Abstract

Researchers have proposed several hypotheses to explain pair-living in primates. In particular, when males are not involved in direct parental care, pairliving may be related to female dispersal, infanticide prevention, or male mate/ resource defense. We aimed to evaluate, through a better understanding of the ranging patterns of avahis, which hypotheses may best account for pair-living in these nocturnal lemurs. We collected focal observations over 26 nights, JuneSeptember 2004, in a littoral forest (Sainte Luce, southeastern Madagascar) on 4 adult radiocollared avahis [Avahi laniger (Tattersall, I. (1982). The Primates of Madagascar. Columbia University Press, New York.) or Avahi meridionalis (Zaramody in Primate Reports 74:9-22, 2006)]. We followed 2 males and 2 females from 2 groups: B, a male-female couple, and A, comprising the parental pair and 1-yr-old female offspring. The adult females birthed in August. We recorded resting and feeding tree points (via global positioning system) for home range calculation through minimum convex polygon and kernel methods. We provide the first quantitative information on the ranging behavior of 2 male and 2 female avahis. Home range/daily path length values (means) are higher than the ones previously reported for the same and other folivorous pair-living lemur species. On average, the 2 females spent more time feeding and traveled shorter distances than the 2 males did. Male-female cohesion (mean values), possibly enhanced by offspring presence, was higher in A and after births than in B and before births, respectively. Although male avahis may be forced into pair-living owing to energy constraints related to size, locomotion, and diet, females might accept pair-living in exchange for indirect territory defense and mate guarding.

Why “monogamy” isn't good enough

“…Physical contact only occurs during the mating season when the male, who defends the range against other males (but not females), maintains proximity [Hilgartner et al, 2012]. Some "dispersed pair-living" species are considered monogamous (e.g., redtailed sportive lemur, L. ruficaudatus; [Hilgartner et al, 2008]; Eastern wooly lemur, Avahi laniger; [Norscia & Borgognini-Tarli, 2008]; Milne-Edwards' sportive lemur, Lepilemur edwardsi; [Thalmann 2001]), though genetic analyses to confirm monogamy have only been reported in red-tailed sportive lemurs (see [Hilgartner et al, 2008[Hilgartner et al, ,2012). In other dispersed pair-living species, extra-pair paternity can be quite high (e.g., P. furcifer's rate of extra-pair paternity is 0.75, n ¼ 4 [Sch€ ulke et al, 2004]).…”

“…We define pair-living as a demographic structure or social organization, in which two adults of opposite sex live together within a home range with their non-reproducing offspring [sensu Norscia & Borgognini-Tarli, 2008]. Fuentes [1998] referred to this category as a "two-adult group."…”

Feeding Patterns and Dietary Profile of Nocturnal Southern Woolly Lemurs (Avahi meridionalis) in Southeast Madagascar

“…Avahis are particularly intriguing in this context because their body mass is at the lower limits for primate folivores (750-1400 g: Kay 1984;Lehman 2007), they are nocturnal (Norscia and Borgognini-Tarli 2008) and thus active at a time when low ambient temperature possibly increases metabolic requirements to remain normothermal (Willmer et al 2000), and their locomotion is energetically expensive (vertical leaping; Warren and Crompton 1997). Like all indriids, Avahi spp.…”

Modelling ranging behaviour of female orang-utans: a case study in Tuanan, Central Kalimantan, Indonesia

“…Most include other home range estimators besides MCP (e.g. Grueter et al 2008, Norscia & Borgognini-Tarli 2008, Neri-Arboleda 2002, NewtonFisher 2003.…”

“…In primatology, researchers have also begun to incorporate kernel methods for range estimates, mainly as an addition to MCP or grid cell methods (e.g. Neri-Arboleda et al 2002, NewtonFisher 2003, Fashing et al 2007, Norscia & Borgognini-Tarli 2008. In their review of home range studies in wildlife biology, Laver & Kelly (2008) found 60% of studies reporting ranges with kernel methods, with 21% of studies solely relying on kernel methods.…”