Reproductive and Life History Parameters of Wild Female <Emphasis Type="Italic">Macaca assamensis</Emphasis>

Information on basic reproductive parameters and life-history traits is crucial for the understanding of primate evolution, ecology, social behavior, and reproductive strategies. Here, we report 4 yr of data on reproductive and life-history traits for wild female Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, northeastern Thailand. During 2 consecutive reproductive seasons, we investigated reproductive behavior and sexual swelling size in 16 females and collected 1832 fecal samples. Using enzyme immunoassays, we measured fecal estrogen and progesterone metabolites to assess ovarian activity and timing of ovulation and to ascertain conceptions and pregnancies. Timing of reproduction was strictly seasonal (births: April–July, 86% in April–June, 4 yr, n = 29; conceptions: October–February, 65% in December–January, 2 yr, n = 17). Females showed no cyclic ovarian activity outside the mating season and conceived in their first or second cycle (mean: 1.2 cycles to conception, n = 13). Gestation length was on average 164.2 d (range: 158–170, n = 10), and females had their first infant at an age of 5 yr (n = 4). Interbirth intervals were bimodally distributed, with females giving birth on average every 13.9 or 23.2 mo. Shorter interbirth intervals were linked to early parturition within the birth season. Most females displayed subcaudal sexual swellings which, however, did not reliably indicate female reproductive status or fertility. Overall, our results fall within the range of findings reported for other macaque species. These results thus add to the growing body of information available for wild macaques, facilitating comparative studies for a better understanding of interspecific differences in social and reproductive patterns.     

Mitochondrial phylogeny, taxonomy and biogeography of the silvered langur species group (Trachypithecus cristatus)

With a distribution ranging from mainland Southeast Asia to the Sunda region, the silvered langur species group is the most widely distributed species complex of the genus Trachypithecus. However, the systematic classification of its members and the phylogenetic relationships among them are less understood, leading to different classification schemes and proposed distribution zones. To address these issues, we sequenced a 573 bp long fragment of the mitochondrial cytochrome b gene from 115 silvered langurs (68 individuals from known origin). According to our data, five monophyletic clades were detected, which refer to the five taxa auratus, cristatus, germaini, margarita and mauritius. The phylogenetic relationships among them are not well resolved, indicating a radiation-like splitting event, which was estimated to have occurred about 0.95-1.25 mya. Within T. cristatus, two major clades were detected, with one comprising specimens from Sumatra, Borneo and the Natuna archipelago, and the other solely individuals from the Malaysian peninsula. According to our findings, we propose to rank all five taxa as distinct species. While T. auratus, T. germaini, T. margarita and T. mauritius seem to be monotypic, T. cristatus should be split into two subspecies, with the Malaysian form being described as new form here. From a phylogeographic perspective, the species group most likely originated on Java. During the early Pleistocene, its range was expanded to the Malaysian peninsula and to the Southeast Asian mainland. Later on, the Malaysian form colonised further regions of the Sunda region, including Sumatra, Borneo and the Natuna archipelago.     

Plant and small mammal richness correlate positively in a biodiversity hotspot

Hotspots of biodiversity are important areas in facilitating an understanding of species richness and its maintenance. Herbivores can increase plant richness by reducing dominant plant species thus providing space for subdominant species. As small mammals are abundant in the Succulent Karoo and therefore might affect plant richness by means of herbivory, we tested if this mechanism might exist in the Succulent Karoo in southern Africa, a biodiversity hotspot due to its extraordinary plant richness. At ten ecologically different study sites we measured plant and small mammal richness and diversity and determined 11 abiotic factors including soil composition, altitude and rainfall. We found positive correlations between plant richness and the number of small mammal species. A general linear model revealed that the number of small mammal species was more important than abiotic factors in explaining variation in plant richness. To test whether small mammals might directly influence plant richness, we studied the influence of the bush-Karoo rat Otomys unisulcatus, a central place forager, on the plant community. The immediate surroundings of occupied O. unisulcatus nests showed significantly higher plant richness than control areas. We conclude that small mammals can have a positive effect on plant richness in the Succulent Karoo. While experimental data are needed to support these correlative results, the results of our study indicate that areas of high small mammal richness should be included in conservation programs of the Succulent Karoo.     

Evolution of Pair-Living in <Emphasis Type="Italic">Phaner furcifer</Emphasis>

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-male-multifemale-units was too costly for males in terms of reduced foraging efficiency.     

MHC class I alleles influence set-point viral load and survival time in simian immunodeficiency virus-infected rhesus monkeys

In HIV-infected humans and SIV-infected rhesus macaques, host genes influence viral containment and hence the duration of the disease-free latency period. Our knowledge of the rhesus monkey immunogenetics, however, is limited. In this study, we describe partial cDNA sequences of five newly discovered rhesus macaque (Mamu) class I alleles and PCR-based typing techniques for the novel and previously published Mhc class I alleles. Using 15 primer pairs for PCR-based typing and DNA sequence analysis, we identified at least 21 Mhc class I alleles in a cohort of 91 SIV-infected macaques. The results confirm the presence of multiple class I genes in rhesus macaques. Of these alleles, Mamu-A*01 was significantly associated with lower set-point viral load and prolonged survival time. Mamu-A*1303 was associated with longer survival and a "novel" Mhc class I allele with lower set-point viral load. The alleles are frequent in rhesus macaques of Indian origin (12-22%). In addition, survival probability of individual SIV-infected rhesus monkeys increased with their number of alleles considered to be associated with longer survival. The results contribute to improve the interpretation and quality of preclinical studies in rhesus monkeys.     

The syndermatan phylogeny and the evolution of acanthocephalan endoparasitism as inferred from 18S rDNA sequences

The phylogeny of the Syndermata (Rotifera: Monogononta, Bdelloidea, Seisonidea; Acanthocephala: Palaeacanthocephala, Eoacanthocephala, Archiacanthocephala) is key to understanding the evolution of acanthocephalan endoparasitism from free-living ancestors. In the present study, maximum likelihood, distance/neighbor-joining, and maximum parsimony analyses have been carried out based on 18S rDNA data of 22 species (four new sequences). The results suggest a monophyletic origin of the Eurotatoria (Monogononta+Bdelloidea). Seison appears as the acanthocephalan sistergroup. Palaeacanthocephala split into an "Echinorhynchus"-and a "Leptorhynchoides"-group, the latter sharing a monophyletic origin with the Eoacanthocephala and Archiacanthocephala. As inferred from the phylogeny obtained acanthocephalan endoparasitism evolved from a common ancestor of Seison and Acanthocephala that lived epizoically on an early mandibulate. Probably, an acanthocephalan stem species invaded the mandibulate host, thus establishing an endoparasitic lifestyle. Subsequently, vertebrates (or gnathostomes) became part of the parasite's life cycle. In the stem line of the Archiacanthocephala, a terrestrial life cycle has evolved, with an ancestor of the Tracheata (Insecta, Myriapoda) acting as intermediate host.     

Social parameters and urinary testosterone level in male chimpanzees (Pan troglodytes)

Studies investigating relationships between social parameters (such as dominance rank, rates of aggressive and sexual behaviors) and androgen (particularly, testosterone) levels in male primates have yielded inconsistent results. In the present study, we address the relationship between androgens, male dominance rank and rank-associated behaviors in two groups of captive chimpanzees, a species characterized by a pronounced dominance hierarchy between adult males. By combining behavioral observations with urinary testosterone (T) measurements, we found that the differences in T concentrations between males were small and not obviously related to their dominance rank. T levels were not related to the rates of initiated aggression and copulatory behavior, but a significant negative relationship between male T level and the rates of strong aggression received was apparent. Our findings, combined with those of others, suggest that any relationship between dominance rank and T depends upon the extent to which individual rank-associated behaviors (e.g. aggressive/sexual) are themselves related to T.     

Different Rates of LINE-1 (L1) Retrotransposon Amplification and Evolution in New World Monkeys

LINE-1 (L1) elements constitute the major family of retrotransposons in mammalian genomes. Here we report the first investigation of L1 evolution in New World monkeys (NWM). Two regions of the second open-reading frame were analyzed by two methods in three NWM species, the squirrel monkey (Saimiri sciureus), the tamarin (Saguinus oedipus), and the spider monkey (Ateles paniscus). Since these three species diverged, L1 has amplified in the Saimiri and Saguinus lineages but L1 activity seems to have been strongly reduced in the Ateles lineage. In addition, the active L1 lineage has evolved rapidly in Saimiri and Saguinus, generating species-specific subfamilies. In contrast, we found no evidence for a species-specific subfamily in Ateles, a result consistent with the low L1 activity in this species for the last ~25 My.     

Perturbations in brain monoamine systems during stress

Monoamines modulate the activity of many neurons and there is evidence that a balanced synthesis of central nervous monoamines is a prerequisite for normal brain functioning. Stress accelerates both release and turnover of brain monoamines and the resulting fluctuations in concentrations affect various parameters within neurotransmitter systems. Acute stress leads to only transient alterations in monoamine systems so that homeostasis can be restored, in contrast, chronic stress accompanied by repetitive and/or prolonged stimulation of monoaminergic neurons can induce a long-lasting imbalance in central nervous neurotransmitter systems. Accordingly, stress-induced changes in brain monoamine systems are suspected to contribute to psychiatric diseases such as depression. The present paper gives a short overview of stress effects on brain monoamines and their receptors.The work presented in this review was in part supported by the German Science Foundation (SFB406, C4 to G.F.). M.J.M. was supported by the DFG grant Fu 174/17–1 and EC Training Through Research (ERBFMBICT 961829).