Patricia Peignot

Kin discrimination in juvenile mandrills, Mandrillus sphinx

Kin selection theory predicts that the evolution of social behaviours will be promoted if these behaviours increase the inclusive fitness of the individuals that perform them, for example by positively affecting relatives. The ability to identify relatives may thus be crucial in maximizing overall fitness. In primate species, whether individuals discriminate paternal relatives and the mechanisms that might permit such discrimination are still the subject of debate. Some researchers have suggested that primates are not able to discriminate relatives in the absence of familiarity. However, recent studies have shown that paternal kin discrimination could emerge from both age proximity and phenotype matching. We investigated the effects of paternal and maternal kinship on the affiliation index of juvenile mandrills, in a semifree-ranging setting. Juveniles biased their behaviour according to kinship. First, when interacting with adult females, both paternal and maternal half-siblings showed more affiliation than unrelated dyads. Affiliation between juveniles and males was also higher among both father–offspring and maternal half-sibling dyads than among unrelated dyads. While these results suggest that juvenile mandrills are able to discriminate paternal relatives, other results do not. Maternal half-siblings had a higher affiliation index than paternal half-siblings and distant kin, the latter showing no significant differences. Finally, when the mechanisms involved in discrimination of paternal kin were analysed, we found no evidence to confirm either the phenotype-matching or the age proximity hypotheses.

Life history correlates of inbreeding depression in mandrills (Mandrillus sphinx)

Inbreeding depression reflects the negative consequences of increased homozygosity at genes that affect fitness. We investigate inbreeding depression in a semi‐free‐ranging colony of mandrills (Mandrillus sphinx), using high‐quality pedigree data, comprising five maternal generations and 20 years of morphological and demographic data. We examine the relationship between inbreeding coefficients and four fitness correlates: two growth parameters (mass and height for age) and longevity in both sexes, and age at first conception in females. Inbreeding was correlated with both growth parameters, but only in females, with inbred females being smaller than noninbred females. Inbreeding was also correlated significantly with age at first conception, with inbred females giving birth earlier in life than noninbred females. We suggest that sex‐biased maternal investment may explain this sex‐differential response to inbreeding, although the lack of a significant association between inbreeding and growth in males may also be due to the provisioned nature of the colony. The surprising relationship between age at first conception and inbreeding may be related to smaller adult size in inbred females, or to their being less able to escape from male sexual coercion.

Learning from the first release project of captive-bred mandrills Mandrillus sphinx in Gabon

Patricia Peignot*, Marie J.E. Charpentier*, Nicolas Bout, Olivier Bourry, Ulrich Massima, Olivier Dosimont,Roxanne Terramorsi and E. Jean WickingsAbstract We report the results of the first release pro-ject of 36 captive-bred mandrills into the Le ´kedi Park,Gabon. A mortality rate of 33% was recorded in the firstyear post-release, with dependent infants the mostaffected age class, as a result of environmental stressand malnutrition. A programme of provisioning en-sured that individuals remained in a good physicalcondition. During the second year the death rate de-creased to 4%, and 6-month survival rate of infantswas 100%. Over time the mandrills extended theirspatial use of the park, although their explorationremained limited. Our results demonstrate that pro-visioning and the lack of knowledge of ecologicalcharacteristicsofthenew,complexseasonalhabitatwerethe likely causes of this situation. After 2 years, re-production and survival appear stable. While habitatpreservation and in situ species protection are the bestconservation options, release projects may constitutea viable short-term solution for particular species. Inthis context, this first release of captive-bred mandrillscould play a role in the future conservation of thisVulnerable species.Keywords Gabon, Le´ke´di Park, Mandrillus sphinx,post-release monitoring, provisioning, rehabilitation,spatial use.IntroductionThe role of translocation and reintroduction pro-grammes in the conservation of endangered specieshas been widely discussed, with particular focus onethical implications, ecological, disease and geneticimpacts on local natural populations, and the long-term monitoring and survival of introduced popula-tions (Wolf et al., 1998; Fischer & Lindenmayer, 2000;Linklater, 2003; Tuberville et al., 2005). The future ofseveral species has been heavily dependent on thereintroduction of captive-bred individuals (Snyder S Stanley-Price, 1989; Moore & Smith, 1991;Csermely & Corona, 1994).Primates are one of the most threatened orders ofmammals (IUCN, 1996) and many species, threatened intheir natural habitat, have been the focus of transloca-tion and reintroduction projects to augment their chan-ces of survival (Horwich et al., 1993; Struhsaker & Siex,1998; Kleiman & Rylands, 2002). To date the long-termsuccess of such programmes has been difficult to assess(Yeager, 1997; Kessel & Brent, 2001; Beck et al., 2002). Thecase of primates is problematic because each speciespresents different and complex socioecological chal-lenges based on social organization and feeding andhabitat preferences (Goodall, 1968; Yeager, 1997).Primates bred in captivity in habitat countries couldhave advantages over ex situ programmes for thereintroduction of threatened species (Snyder et al.,1996) because such programmes present more economicalternatives. The Centre International de RecherchesMe´dicales de Franceville (CIRMF) in Gabon establisheda semi-captive ranging breeding colony of Mandrillussphinx for non-invasive biomedical research in the early1980s. The initial group of 15 founders (bushmeat orphansaged 1-8 years) had reached .100 individuals by 2002,resulting in overcrowding and habitat degradation. Theinstigation of contraceptive measures will limit futurebreeding but cannot alleviate current conditions. Hence,alternative measures to reduce numbers were sought.

Consequences of a One-male Harem Reproductive System and Inbreeding in a Captive Group of Cercopithecus solatus

In closed captive populations, where dispersal is not possible, kin recognition and behavioral avoidance are the only mechanisms by which closely related individuals can avoid inbreeding. In the absence of avoidance, a loss of genetic diversity is inevitable in successive generations.In the 1980s, the CIRMF in Gabon established a small breeding group of sun-tailed monkeys (Cercopithecus solatus) with 4 individuals, and subsequently 17 births have been registered. We aimed to describe via microsatellite genotyping the reproductive system in the colony of Cercopithecus solatus, to evaluate the loss of genetic diversity with succeeding generations, and to evaluate consequences of inbreeding depression on a measure of the lifespan reproductive success of females giving birth to inbred vs. noninbred offspring. During the 11-yr period for which data are available, only alpha males sired offspring, confirming a one-male social organization. They reproduced only during their period of tenure. Two of the 3 alpha males were responsible for all the infants born. Genetic diversity decreased and inbreeding coefficients increased with successive generations. Interbirth interval was increased following the birth of an inbred infant, indicating possible increased maternal costs of rearing inbred infants. Loss of genetic variability in this captive group of sun-tailed monkeys has led to significant inbreeding depression and demonstrates the importance of male-mediated gene flow in restricted one-male harem breeding groups.

Relatedness and Social Behaviors in Cercopithecus solatus

Inclusive fitness and kin selection theories predict that organisms will evolve biased behavior toward kin when the inclusive fitness benefits outweigh the costs of such behaviors. Researchers have long observed that primates bias their behavior toward relatives, particularly maternal kin. We examined the effect of kinship on social behaviors in a semifree-ranging colony of Cercopithecus solatus, a poorly studied forest guenon species. We used microsatellite loci and paternity analyses to determine the degree of relatedness between individuals, as well as kinship. Individuals biased some of their behavior according to relatedness. Specifically, related individuals are more spatially associated and less aggressive toward each other. When we replaced the relatedness coefficients with defined kin categories, Cercopithecus solatus seemed to behave preferentially toward maternal kin versus paternal kin. Even though the setting of the colony and the small sample size limit our conclusions, we discuss the potential implications of our finding for the study of the impact of kin selection in primate social relationships.