Molecular separation of Oesophagostomum stephanostomum and Oesophagostomum bifurcum (Nematoda: Strongyloidea) from non-human primates.

The ITS-2 sequences for adult specimens of Oesophagostomum stephanostomum from the common chimpanzee and Oesophagostomum bifurcum from the Mona monkey were determined. For both species, the length and GC content of the ITS-2 sequences were 216 bp and 43%, respectively. While there was no unequivocal sequence difference among individual worms representing each of the two species, five (2.3%) interspecific nucleotide differences were detected. These differences were associated with the presence of unique restriction sites in the ITS-2 sequence of 0. stephanostomum for multiple endonucleases of diagnostic value for the differentiation of the two taxa by restriction analysis. Pairwise comparisons of the ITS-2 sequences of O. stephanostomum and O. bifurcum with published ITS-2 sequences for five different congeners indicated that these species from the subgenus Conoweberia are closely related, in accordance with previous morphological studies.

Use of Vernonia amygdalina by wild chimpanzee: possible roles of its bitter and related constituents.

Bitter principles and related constituents have been isolated from Vernonia amygdalina (Compositae), a plant ingested by wild chimpanzees sometimes suffering from parasite-related diseases in the Mahale Mountains National Park, Tanzania. These isolated constituents were the known sesquiterpene lactones (vernodalin, vernolide, hydroxyvernolide), and new stigmastane-type steroid glucosides (vernonioside A1-A4: for bitter tasting constituents and vernonioside B1-B3; for nonbitter related constituents). Antiparasitic activity tests of these constituents together with quantitative analyses of the major active constituents, vernodalin and vernonioside B1, supported the hypothesis that Mahale chimpanzees control parasite-related diseases by ingesting the pith of this plant, found to contain several steroid-related constituents. While the major active steroid-related constituents (vernonioside B1 and its primary aglycone, vernoniol B1) do not taste bitter themselves, it was hypothesized that the highly bitter constituents including vernodalin may play an important role as signals to the ingester guiding their choice of the appropriate plant, plant part, and possibly also as signals which help to control the amount of intake.

Why dominants do not consistently attain high mating and reproductive success: A review of longitudinal Japanese macaque studies.

There is wide interest in the effects of reproductive biology, mating partner preference, and rank on mating success (MS) and reproductive success (RS) in primates. In particular, theory stresses importance on the mechanisms for attaining RS. Most theory hedges on competitive ability and priority of access to resources, whether they be food or estrous females. However, the majority of data used in favor of such hypotheses come from relatively short-term studies. We review these hypotheses based on long-term data from provisioned and unprovisioned populations of Japanese macaques. Neither MS nor RS were consistently attained by high-ranking males and females. For males, female choice and mating partner preference is seen to over-ride most male-male competitive behaviors likely to affect MS and RS through priority of access to estrous females. Long-term mating patterns driven largely by female partner preferences, results in decreasing MS and RS for older higher-ranking males. The long-term trend for females to prefer less familiar or novel partners results in higher MS and RS for younger, middle-ranking males. The effects of this vary according to troop size and the duration of male tenure. For females, no consistent trend was recognized for rank related RS in either provisioned or unprovisioned troops. Non-reproductive mating may provide differential benefit to high-ranking females for access to limited food resources in some habitats but overall the relationship was inconclusive. Distribution and defendability of food resource, rather than provisioning per se may be more important.

Diversity and host specificity of Blastocystis in syntopic primates on Rubondo Island, Tanzania.

The isolated ecosystem of Rubondo Island National Park, Tanzania is an interesting model site, inhabited by an assembly of primate species with various histories: two introduced primate species, Pantroglodytes (chimpanzee) and Colobus guereza (colobus), and a single indigenous species Chlorocebus aethiops pygerythrus (vervet monkey). Apart from important lessons for future introduction/re-introduction projects, Rubondo National Park offers a unique place to study the patterns of transmission of primate parasites and their host specificity. Blastocystis was detected using standard microscopy, together with PCR-based determination and the prevalence and subtype identification of Blastocystis was determined in each primate species. Subtype (ST) 1 was detected in all three Rubondo primate populations; ST2, ST3 and ST5 were found in colobus and vervet monkeys. All chimpanzee isolates of Blastocystis belonged exclusively to ST1, which formed a discrete group, suggesting that Rubondo chimpanzees are colonized by a single, host-specific Blastocystis strain that circulates among the members of the group. Phylogenetic analysis indicated that transmission of Blastocystis did not occur between Rubondo primate populations. Observed host specificity of Blastocystis provides a new understanding of the transmission and distribution of Blastocystis among sympatric hosts under natural conditions.

Fruit availability, chimpanzee diet, and grouping patterns on Rubondo Island, Tanzania.

We examined seasonal patterns of fruit availability, dietary quality, and group size in the descendants of an introduced chimpanzee population on Rubondo Island, Tanzania. The site has supported a free-ranging population without provisioning for 40 years. Our goals were to determine whether Rubondo chimpanzees experience periods of fruit shortage, and whether they respond to changes in fruit availability similarly to chimpanzees at endemic sites. We indexed the fruit availability of tree and liana species on transects stratified across three chimpanzee ranging areas. We used fecal analyses to evaluate seasonal changes in diet, and used data on party size and nesting group size to examine seasonal patterns of grouping. Tree fruit availability was positively correlated with rainfall, with a period of relative tree fruit scarcity corresponding with the long dry season. Liana fruit availability was not related to rainfall, and lianas exhibited less variable fruiting patterns across seasons. Fruits made up the majority of the chimpanzee diet, with lianas accounting for 35% of dietary fruit species. Fruits of the liana Saba comorensis were available during all months of phenological monitoring, but they were consumed more when tree fruit was scarce, suggesting that Saba comorensis fruits may be a fallback food for Rubondo chimpanzees. There were no increases in consumption of lower-quality plant parts between seasons, and there were no changes in group size between seasons. These results contrast with evidence from several endemic chimpanzee study sites, and indicate that Rubondo chimpanzees may have access to abundant and high-quality foods year round.

Influences of female partner preference on potential reproductive outcome in Japanese macaques.

The immediate effects of female partner preference on male mating behaviors and its potential influence on male reproductive success and conception in the Japanese macaque (Macaca fuscata) were analyzed. Although male dominance interactions probably led to low-ranking males having more single-day consortships and high-ranking males more multi-day consortships, dominant males were unable to prevent females from mating with preferred subordinate males. Ultimately, there was no marked difference in the number of estimated offspring sired. Females chose not to mate with certain males and actively mated with others, suggesting that female partner preferences do affect conception. Evidence for this was found in paternity estimates, which reflected observed preferences for particular middle-ranking young adult males.

Social behavior and hormonal correlates during the perinatal period in Japanese macaques.

This work assessed the changes in both social interactions and estrogen metabolite excreted in feces in eight group-living Japanese macaques (Macaca fuscata). We tested the hypothesis that the social behavior of pregnant females shows significant changes during the late prepartum and early postpartum period. We also tested the hypothesis that the marked fluctuation in estrogen levels during the perinatal period is associated with the changes in social behavior. We found that pregnant females withdrew from the social life of their group in preparation for parturition and only slowly regained their normal social activity after delivery. These changes were correlated with the fluctuation in estrogen conjugate excreted in feces, giving further evidence that hormones can enhance responsiveness to the infant and may predict maternal competence in macaques. We also found that the high frequency of self-grooming by pregnant females during the perinatal period may be a functional way to improve the quality of care toward an infant by a simple shifting from the care for oneself to the care for the infant after parturition.

Mineralogical and chemical interactions of soils eaten by chimpanzees of the Mahale Mountains and Gombe Stream National Parks, Tanzania.

Termite mound soils eaten by chimpanzees of the Mahale Mountains and Gombe National Parks, Tanzania, have mineralogical and geochemical compositions similar to many soils eaten by higher primates, but release very low levels of either toxic or nutritional inorganic elements to solution at acid pH. Comparison with control (uneaten) soils from the same areas showed lower levels of carbon and nitrogen in the eaten soils, a relationship confirmed by surface analysis. Surface analysis also revealed lower levels of iron on particle surfaces versus interiors, and higher levels of iron on ingested versus control soil particle surfaces. The soils can adsorb dietary toxins, present in the plant diet or those produced by microorganisms. Taking the toxic alkaloids quinine, atropine, sparteine, and lupanine as examples, it is evident that soils from Mahale have a very good adsorptive capacity. A new adaptive advantage of geophagy is proposed, based on the prevention of iron uptake. The behavior of the soils in vitro is consistent with the theory that geophagy has a therapeutic value for these chimpanzees.

Toward the chemical ecology of medicinal plant use in chimpanzees: The case ofVernonia amygdalina, a plant used by wild chimpanzees possibly for parasite-related diseases.

The bitter and related constituents have been isolated fromVernonia amygdalina (Compositae), a plant ingested by wild chimpanzees possibly suffering from parasite-related diseases in the Mahale Mountains National Park, Tanzania. Isolated from the plant were four known sesquiterpene lactones, seven new steroid glucosides, and two aglycones of the glucosides. The sesquiterpene lactones showed significant in vitro antischistosomal, plasmodicidal, and leishmanicidal activities. Antischistosomal activity was also found for the major steroid glucoside, vernonioside B1. A trend in the glucosides to show significant antischistosomal, plasmodicidal, and amebicidal activities when the sugar moiety was removed, was observed. Vernodalin, judged as the most significant constituent for antiparasitic activities in vitro, was tested for in vivo antischistosomal effect. It was, however, highly toxic to the cercaria-infected mouse. Chimpanzees have been only rarely observed to ingest anything but the pith of the young stem. The occurrence of vernonioside B1 and its aglycone vernoniol B1, the major constituents among the steroid-related constituents, were detected at significant levels in the pith. However, vernodalin was abundant only in the leaves and bark. Thus, chimpanzees at Mahale were hypothesized to control parasite-related diseases by ingesting the young pith of this tree containing steroid-related constituents.