Search

Sexual selection theory predicts that in group-living mammals, male reproductive tactics can lead to high reproductive skew in favor of dominant individuals. In sifakas ( Propithecus verreauxi), a group-living primate with extremely seasonal reproduction, male reproductive success is highly skewed because dominant males sire almost all offspring despite a tendency toward an even adult group sex ratio. To understand the underlying behavioral mechanism resulting in this rank-related reproductive skew in male sifakas, we studied mate-guarding as a potential reproductive tactic. Behavioral observations of dominant males and adult females in combination with hormonal determination of timing of female receptivity in 9 groups at Kirindy Forest revealed that dominant males spent more time in proximity to females when they were receptive and were responsible for the maintenance of this proximity. Results also indicated that monopolization of receptive females was facilitated by both estrous asynchrony within groups and by the ability of dominant males to obtain olfactory cues as to the timing of female receptivity. Although dominant males engaging in mate-guarding are expected to experience various costs, there was no evidence for decreased foraging behavior and only a trend toward increased aggression between dominant and subordinate non-natal males within groups. Our results are in accordance with the hypothesis that dominant males use mate-guarding to monopolize receptive females and that it is one proximate mechanism that contributes to the high reproductive skew observed within the population of male sifakas at Kirindy. [ABSTRACT FROM AUTHOR]

The objective of our study was to investigate the spatial distribution and genetic structure of a solitary primate at the microgeographical scale of adjacent local populations. We obtained spatial data and tissue samples for mtDNA analysis from 205 gray mouse lemurs (Microcebus murinus) captured along transects and within 3 grid systems within a 12.3 km2 area in Kirindy Forest, western Madagascar. Our capture data revealed that, even though the forest was continuous, gray mouse lemurs were not evenly distributed, and that daily and maximum dispersal distances were significantly greater in males. The frequency distribution of 22 mtDNA D-loop haplotypes was highly skewed. Nine haplotypes were unique to males, indicating male-mediated gene flow from surrounding areas. The geographic distribution of haplotypes revealed that males were also more dispersed than females. Females with the same haplotype showed a tendency towards spatial aggregation, and the correlation between genetic and geographic distances was higher in females. In several areas of the forest, however, spatially clustered females were not of the same haplotype, and females were not always found in clusters. Hence, in contrast to suggestions from previous studies, matrilineal clustering is not the only way females are socially organized. In addition, our study revealed heterogeneity and patterns in population structure that were not evident at smaller spatial scales, some of which may be relevant for designing conservation strategies. [ABSTRACT FROM AUTHOR]

Mandrill is a vulnerable Old World primate living in the rain-forests of central Africa. This species is currently facing two major human encroachments: habitat destruction and bush-meat trade. The total population size remains unknown in the wild, but it is suspected to have recently declined. We developed and characterized 24 new polymorphic microsatellite markers from the next-generation sequencing data using 66 individuals from a wild population. The number of alleles per locus ranged from 2 to 9 and the observed heterozygosity from 0.12 to 0.92. Conveniently, the developed markers did not amplify human DNA avoiding cross-species contamination. These microsatellites will be especially useful for studies based on sensible DNA, including population genetics analyses to studies in behavioral ecology. [ABSTRACT FROM AUTHOR]

Gastrointestinal helminth-microbiota associations are shaped by various ecological processes. The effect of the ecological context of the host on the bacterial microbiome and gastrointestinal helminth parasites has been tested in a number of ecosystems and experimentally. This study takes the important step to look at these two groups at the same time and to start to examine how these communities interact in a changing host environment. Fresh faecal samples (N = 335) from eight wild Eulemur populations were collected over 2 years across Madagascar. We used 16S ribosomal RNA gene sequencing to characterise the bacterial microbiota composition, and faecal flotation to isolate and morphologically identify nematode eggs. Infections with nematodes of the genera Callistoura and Lemuricola occurred in all lemur populations. Seasonality significantly contributed to the observed variation in microbiota composition, especially in the dry deciduous forest. Microbial richness and Lemuricola spp. infection prevalence were highest in a previously intensely logged site, whereas Callistoura spp. showed no such pattern. In addition, we observed significant correlations between gastrointestinal parasites and bacterial microbiota composition in these lemurs, with 0.4–0.7% of the variation in faecal bacterial microbiota composition being explained by helminth infections. With this study, we show effects of environmental conditions on gastrointestinal nematodes and bacterial interactions in wild lemurs and believe it is essential to consider the potential role of microbiome-parasite associations on the hosts' GI stability, health, and survival. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the paper "Workshop: Data management in long-term field studies," by P.M. Kappeler, to be presented at the 21st Congress of the International Primatological Society at the Imperial Resort Beach Hotel in Entebbe, Uganda, from June 25-30, 2006.

The article presents an abstract of the paper "Feeding Ecology and Activity Patterns of Female Microcebus berthae and Sympatric M. murinus (Cheirogaleidae)," by M. Dammhahn and P. M. Kappeler, at the Twenty-First Congress of the International Primatological Society to be held in Entebbe, Uganda, on June 25-30, 2006.

The article presents the abstract of the paper "Morphometric Aspects of Species Diversity of Mouse and Dwarf Lemurs (Cherigaleidae) by R.M. Rasoloarison and P.M. Kappeler to be presented at the 21st Congress of the International Primatological Society in Entebbe, Uganda from June 25-30, 2006.

The primates of Madagascar (Lemuriformes) deviate from fundamental predictions of sexual selection theory in that polygynous species lacksexual dimorphism, have even adult sex ratios and often live in female-dominated societies. It has been hypothesized that intrasexual selection in these species is either reduced or primarily focused on traits related to scramble competition. The goal of this study was to examine these hypotheses by studying the mating system of a solitary nocturnal species, Mirzacoquereli. During a 4-year field study in western Madagascar, I captured and followed 88 individually marked animals. I found that adult males were significantly larger than females, providing the first evidence for sexual size dimorphism in lemurs. In addition, the adult sex ratio was biased in favour of females in 3 outof 4 years. There was no significant sex difference in canine size, however. Males showed pronounced seasonal variation in testis size with a 5-fold increase before and during the short annual mating season. During the mating season, males had more injuries than females and more than quadrupled their home ranges, overlapping with those of more than ten females, but also with about the same number of rivals. Only about one social interaction per 10 h of observation was recorded,but none of them were matings. Together, these results indicate thatthese solitary lemurs are clearly subject to intrasexual selection and that male-male competition is primarily, but not exclusively, of the scramble type. In addition, they suggest that the above-mentioned idiosyncracies may be limited to group-living lemurs, that social systems of solitary primates are more diverse than previously thought, and that the temporal distribution of receptive females is responsiblefor this particular male mating strategy. [ABSTRACT FROM AUTHOR]