Fabien Génin

Gummivory in Cheirogaleids: Primitive Retention or Adaptation to Hypervariable Environments?

Gummivory in cheirogaleids, apart from the specialist gummivore Phaner, is often viewed as a fall-back diet; animals are forced to consume gums when other foods are unavailable. We propose an alternative explanation that cheirogaleid gummivory is an adaptation to hypervariable environments. First, we compared morphological adaptations to gummivory evinced by cheirogaleids and other gummivorous primates. Despite convergent trends, adaptations to gummivory are quite variable. Second, a long-term field study of the reddish-grey mouse lemur, Microcebus griseorufus, in the highly variable xerophytic forest of southern Madagascar reveals this species to be the most specialized gummivore of all known mouse lemurs. Third, a comparison of the nutritional composition of gums and fruits consumed by M. griseorufus shows these two food types to be of equivalent nutritive content. Gums consumed by M. griseorufus are exuded all year round, increasing the predictability of food availability in a hypervariable habitat, while fruit availability exhibits high intra- and inter-annual variation. Finally, we compared the global distributions of gummivorous mammals with a map of the regions subject to El Nino-related droughts, which indicated a strong congruence between gummivory and hypervariability.

Who sleeps with whom? Sleeping association and socio-territoriality in Microcebus griseorufus

Abstract Although mouse lemurs are solitary foragers, they are known to form sleeping associations. I examined several factors that could influence the choice to sleep communally and the composition of sleeping associations in Microcebus griseorufus, an inhabitant of the subarid spiny forest of southern Madagascar. These include the quantity and quality of available sleeping sites, socio-territoriality, predation risk, and thermoregulation. I radiotracked 26 individuals (12 males and 14 females) and recorded 222 uses of 151 sleeping sites. Mouse lemurs slept most often in tree forks and tangles of vegetation and preferred sleeping sites in Alluaudia spp. (36%) and Euphorbia spp. (30%), 2 very common tree genera in the spiny forest. Sleeping associations allowed the animals to use larger and more extensively overlapping home ranges and to have access to more food. Predation risk was much higher during nocturnal activity than during diurnal rest. Sleeping groups were small, usually pairs. Animals showed no signs of vigilance in sleeping sites and did not huddle consistently. Sleeping sites were chosen for their inaccessibility to predators and were well buffered against high and low ambient temperatures. Therefore, sleeping association was better explained by social territoriality than by predation pressure or thermoregulation.

A new galago species for South Africa (Primates: Strepsirhini: Galagidae)

The primate fauna of South Africa has historically been viewed as comprising three diurnal cercopithecoid taxa — chacma baboons (Papio ursinus), vervet (Chlorocebus pygerythrus) and samango monkeys (Cercopithecus albogularis) — and two nocturnal lorisoid species — the thick-tailed greater galago (Otolemur crassicaudatus) and the southern lesser galago (Galago moholi). Here we report the positive identification of a third galago species within South Africas borders: the Mozambique dwarf galago or Grants galago, Galagoides granti (Thomas and Wroughton, 1907). The taxon was previously held to be restricted to Mozambique, eastern Zimbabwe, Malawi and Tanzania, but we have also observed it in the sand forest of Tembe Elephant Park and the Tshanini Community Reserve, near the Mozambique border. The species was formerly mistaken for Galago moholi, erroneously (we believe) extending the range of the latter species into northern KwaZulu-Natal. In South Africa the two small galagos are unlikely to have overlapping ranges: Galago moholi prefers dry savanna woodlands, whereas Galagoides granti is apparently confined to dry sand forest. However, both species may coexist with the larger and more widespread Otolemur crassicaudatus, an inhabitant of moist savanna, forest edge and thicket. The true South African ranges of both small galago species need to be ascertained.

Venus in Fur: Female Power in Mouse Lemurs Microcebus murinus and M. griseorufus

Female power is a characteristic peculiar to lemurs, involving dominance in agonistic interactions, and other strategies enabling priority of access to resources. I investigated three strategies of power used by the females of two mouse lemur species, both in captivity and in the wild. In both species, most agonistic encounters involved intersexual dyads, and the females won most of the observed agonistic interactions, expressing unambiguous female dominance. I observed female priority of food access on both species, the males usually avoiding interactions with females on the resources. In 3/4 resource trees and in 4/10 supplemented food sources, the 7 males I observed in the vicinity of the resources (<10 m) never consumed them. Moreover, animals found in sleeping associations (11/14 females and 7/12 males) showed higher body masses, larger home ranges, and higher proportions of fruit foraging than isolated animals.

Sharing the burden: A neutral approach to socioecological theory

OBJECTIVE The socioecological model (SEM) is a popular collection of controversial models purporting to explain mating systems in terms of ecological and social parameters. Despite its guise of objectivity, several of its hypotheses assume Victorian gender stereotypes of active, competing males heedlessly sowing their seeds, and cautious, passive females, imprisoned by greater costs of reproduction and their consequent resourceߚdependence. METHODS We enter this debate by taking a previously neglected explanatory approach borrowed from species theory. According to the Recognition Concept of sexual species, the unit of reproductive success/fitness is irreducible to fewer than two integrated subparts (minimally a male and a female). Phyletic changes in mating systems logically effect changes in fertilization systems, leading to reproductive isolation. We take our primary assumption of the average equivalence of female and male contributions to successful reproduction from the writings of the natural philosopher, Antoinette Blackwell. RESULTS We revisit the SEM with its contradictions and extrapolations, and develop a genderߚneutral alternative hypothesis termed SpecificߚMate Contact (SMC), centered on two fundamental mating strategies: sexual animals may behave as synchronous mateߚattractors or asynchronous mateߚseekers, generating four possible mating system combinations (monogamy: two attractors; promiscuity: two seekers; polygyny: male attractor and female seeker; polyandry: female attractor and male seeker). CONCLUSIONS Our approach predicts all known primate mating systems using a neutral (nonߚsexist) principle. The approach is also neutral in the sense that it does not invoke either competition or cooperation: fertilization success is considered a posteriori and males and females are coߚadapted to this end rather than cognitively cooperative.

What’s in a Name? Higher Level Taxonomy of the Prosimian Primates

The systematics and classification of the strepsirhine and tarsioid primates are contentious subjects. In compiling this volume, we have adopted a taxonomy that best fits our understanding of the evolution of these groups, and the spirit and intention inherent in systematic theory. In this chapter, we clarify and explain our choices regarding the title of this book and higher level taxonomic assignments.