Evolution of Pair-Living in Phaner furcifer

Abstract

Pair-living evolved several times independently in the primate lineage and most likely for more than one reason. Currently, there are 7 hypotheses regarding the evolution of pair-living in primates. They may explain several but not all cases. I investigated the applicability of the explanations to fork-marked lemurs Phaner furcifer. I used information from a long-term study on 8 fork-marked lemur families in Kirindy Forest to evaluate the hypotheses. Fork-marked lemurs live in uniform dispersed pairs, which share and defend a territory but spend three-quarters of their activity time apart from each other. Unconditional female dominance and lack of permanent close association between pair-partners disqualify most hypotheses. Lack of male parental care and long travel distances in small home ranges disqualify other explanations. I conclude that there is no support a priori for any current pair-living hypothesis and that the newly formulated intersexual-feeding-competition hypothesis best explains the evolution of pair-living in fork-marked lemurs. Accordingly, female range exclusivity evolved first as a consequence of intense feeding competition. Subsequently, indirect feeding competition drove females to accept a single male to share their territory as a defense against feeding competition from males whose ranges unsystematically overlap those of several females. This situation led to pair-living because formation of dispersed one-malemultifemale-units was too costly for males in terms of reduced foraging efficiency.

Infanticide as Sexual Conflict: Coevolution of Male Strategies and Female Counterstrategies

“…Second, it is also not the case that male infanticide is unreported in other taxa with lower L/G ratios, but in those cases the sexually selected mechanism has been less implicated than alternative hypotheses (see below). Finally, L/G ratios are important, but other factors may explain the rarity of infanticide in some mammals, for example, ecologically determined sexual segregation, (Kunz and Ebensperger 1999), caching of infants as an antipredator strategy (Schülke 2005), need for hibernation (Thalmann 2001), or even phylogenetic inertia (Ebensperger 2001).…”

Why “monogamy” isn't good enough

“…Recent phylogenetic reconstructions indicate that pair-living evolved independently several times in the Primate Order [Kappeler & van Schaik, 2002], and it also appears to have evolved independently several times just within the Lemuroidea superfamily [Lukas & Clutton-Brock, 2013;Sch€ ulke, 2005;Shultz et al, 2011]. Lemuroidea demonstrate a great deal of variation in the degree to which pairs of one adult male and one adult female are bonded and mate exclusively.…”

“…Pairs work together to defend home ranges and territorial signaling varies with resource availability [Fuentes, 1998;Hilgartner et al, 2012;Sch€ ulke, 2005;Zinner et al, 2003]. The D index of defensibility [Mitani & Rodman, 1979] compares day range and home range size to determine whether or not a group can feasibly monitor and defend home range boundaries.…”

“…Though they are often associated, each is a separate component of a social system [Kappeler & van Schaik, 2002], and these components do not always covary. For example, pair-living species are commonly bonded [e.g., titi monkeys, Callicebus; Anzenberger et al, 1986], but bonding is not necessary for pair-living (e.g., red-tailed sportive lemurs, Lepilemur ruficaudatus; [Hilgartner et al, 2012]; fork-marked lemurs, Phaner furcifer; [Sch€ ulke, 2005]). Similarly, pair-living species commonly mate monogamously (e.g., Azara's owl monkey, Aotus azarae; [Huck et al, 2014]), but monogamous mating is not required (e.g., fat-tailed dwarf lemur, Cheirogaleus medius; [Fietz et al, 2000]).…”

Scientific Bases for a Participatory Forest Landscape Management

“…If the deforestation in the dry region of Central Menabe continues at the present rate, the forest will disappear and no longer be capable of ensuring the different services it provides (amongst others the maintenance of biodiversity and a CO2 sink) (Sorg et al 2003). Nor will it be able to provide the numerous resources for the local populations (nutri- , Schülke 2005) and land-use issues (Favre 1989, Raonintsoa 1996, Paupert-Razafiarisera 2005) exists for the Kirindy region. This is an extremely rare situation for a Madagascan dry forest landscape (Dufils 2003).…”