Puberty

The goal of this project is to investigate the development of pronounced secondary sexual characters (SSC) in female Macaca sylvanus during puberty and the continuation of SSC function and use as reproductive adults. In the analysis we shall compare morphological development with the physiological condition and behavior in peripubertal and post pubertal individuals. This species has extreme expression of SSC during puberty which is maintained even outside of mating in adults. Macaque societies are promiscuous with seasonally limited reproduction. Females develop anogenital swellings in autumn before ovulation and maintain them with or without gestation until spring or parturition. In both adolescents and adults, differing degrees of swelling may be related to attractiveness and effect competition for males and resources via changes in inter- and intrasexual interactions. Social status, behavior, swelling morphology and physiological parameters (endocrine and conditional) will be investigated in focus individuals over two reproductive and non reproductive periods. This will allow analyses of the pubertal to postpubertal state. In addition comparisons of the behavior and morphology of adult and adolescent females previously investigated in 1995 will enable us to document the continuity of development and expression. Four specific questions are addressed in this study: i. Do individuals with different extents of AS behave in a socially distinct manner? ii. What relationships can be found between the dominance rank, social stress (definition, see below) and the different extents of AS? iii. Are there correlations among endocrine levels or body mass and AS development? iv. Is the AS morphology and the social behavior of pubertal females carried over into the postpubertal and adult phase? The underlying rationale here is that pubertal morphology, physiology and social behavior may imprint reproductive and behavioral strategies of adults. In effect, that the coherence of development in these parameters has consequences and continuity in adults.

The goal of the project was to investigate the development of pronounced secondary sexual characters (SSC) in female macaques during puberty and the continuation of SSC function and use as reproductive adults. During the project the work was extended from Barbery macaques with their anogenital swellings to Japanese macaques, which also show facial reddening as a secondary sexual character. In the analysis we compared morphological expression with the physiological condition and the behavior of individuals. Both species have extreme expressions of SSC`s during puberty, which, are maintained even outside of mating in adults. Both macaque societies are also promiscuous with seasonally limited reproduction. Females develop their anogenital swellings in autumn before menstral cycles begin and maintain them with or without gestation until parturition or late spring. In both adolescents and adults, differing degrees of anogenital swelling were shown to be related to attractiveness and to effect competition for males and resources via changes in inter- and intrasexual interactions. Specific results have demonstrated that although swelling is associated with the endocrine state of an individual it is not affected by dominance rank. To this, individuals with larger swellings can use interactions with males to lessen the effects of stressful situations. This is evident in the frequencies of intersexual grooming and patterns of adrenal activity (Cortisol secretion). Japanese macaques females also exhibit conspicuous red coloration of the face during the mating season. It had been suggested that the intensity of coloration was related to ovulation as a signal for receptivity. Our investigations showed that it was independent of the anogenital swellings. To this pubertal females expressed significantly less intense facial reddening along with higher weekly variation. The results indicated that face reddening is a maturity related phenomenon perhaps associated with intrasexual dominance. In another study the relationships among the SSC`s and steroid hormone secretion from the gonads and adrenals were documented and compared to conception rates in this species. Individual age and rank were analysed as confounding factors. These factors had no influence on the conception rate. Although dominant adult animals had higher hormone metabolite concentrations (sexual steroids and cortisol) and more intensive face reddening the factors were not related to differences in reproduction even when comparing age classes. High-ranking females with the reddening did have higher oestrogen and cortisol metabolite concentrations during mating than low ranking females. Animals, which conceived during the mating season had showed increases in oestrogen concentrations before mating, during the asexual phase. A positive correlation between the sexual steroid concentration and the cortisol metabolites was found. A suppressive effect of cortisol on the sexual physiology due to social stress could not be documented. The time of the previous birth seemed to be the main factor, which influenced conception. Although the animals, which did not conceive (6 of 7 lactating), had oestrogen increases during the mating season, the number of observed copulations and detected seminal plugs was lower than the animals, which conceived. In Barbery macaques of Gibraltar, faecal extracts of samples were collected during mating, in late pregnancy and the early postpartum period. These samples were used to validate immunological assay for pregnanolone (a progesterone metabolite) and estradiol. For Cortisol, the adrenal stress response was monitored in faecal metabolites. Here an antibody produced against 5ß-androstandiol appeared to produce the most reasonable results. In the field, the size of the anogenital swelling went through clear fluctuations in all females. During the mating season individuals had between 1 and 3 maximum swelling periods. In comparison to the adult females (multi/primipar) the adolescent females showed the first signs of swelling earlier. In general, the time from first sign of swelling increase to first maximum was longer in the first cycle (x=25.9 11.2 days) than in the second (x=11.3 5.6 days). Comparison of the length of maxima between adolescent and adult females revealed that the adolescent females also had a longer periods (38, 23 and 38 vs. 2-18 days). SSC evaluation has revealed that the maximal size is not related to the age of the female. There is a high inter-individual variability in both young (nulliparous) and adult (multiparous) females. The analyses of endocrine data have demonstrated that the collection of physiological data in the field is possible. To this it is possible to specifically identify the time points for ovulation, insemination and implantation. The resulting data set will represent a significant contribution to the understanding of how these SSC`s develop and for what purpose they are used. This intern will definitely aid our understanding of primate societies.