Resource partitioning in sympatric langurs and macaques in tropical rainforests of the central Western Ghats, south India.

In a competitive sympatric association, coexisting species may try to reduce interspecific interactions as well as competition for similar resources by several ecological and behavioral practices. We studied resource utilization of three sympatric primate species namely, lion-tailed macaques (Macaca silenus), bonnet macaques (M. radiata) and Hanuman langurs (Semnopithecus entellus) in a tropical rainforest of the central Western Ghats, south India. We studied resource use, tree-height use, foraging height, substrate use when consuming animal prey and interspecific interactions. The results revealed that across the year, there was very limited niche overlap in diet between each species-pair. Each primate species largely depended on different plant species or different plant parts and phenophases from shared plant species. Primate species used different heights for foraging, and the two macaque species searched different substrates when foraging on animal prey. We also recorded season-wise resource abundance for the resources shared by these three primate species. While there was low dietary overlap during the dry season (a period of relatively low resource abundance), there was high dietary overlap between the two macaque species during the wet season (a period of high resource abundance for the shared resources). We observed only a few interspecific interactions. None of these were agonistic, even during the period of high niche overlap. This suggests that the sympatric primate species in this region are characterized by little or no contest competition. Unlike in some other regions of the Western Ghats, the lack of interspecific feeding competition appears to allow these primates, especially the macaques, to remain sympatric year-round.

Diet and dietary-niche breadth of diurnal rain forest primates in the Central Western Ghats, India.

We studied the feeding ecology of 3 sympatric primate species, the lion-tailed macaque (Macaca silenus), bonnet macaque (Macaca radiata) and Hanuman langur (Semnopithecus entellus), in a tropical rain forest of the Central Western Ghats, India. Since the availability of leaves is much higher than that of fruits, we expected that the primarily folivorous langurs would use a larger number of resources than the primarily frugivorous macaques. Since fruits are a relatively total resource, unlike leaves, of which only selected parts are consumed, we expected that the primarily frugivorous macaques would use resources more proportionately than the folivorous langurs, resulting in a wider food niche breadth in macaques. We collected data on these primate species over a period of 2 years using scan sampling in a contiguous rain forest. We calculated Levin's standardised food niche breadth for each species. Langurs used a larger number of tree species than macaques, but their niche breadth was narrower than that of macaques. The majority of their diet (over 50%) came from only a few trees in the case of all three primate species. Long-term data are provided herein for the first time on the feeding ecology of bonnet macaques and Hanuman langurs in a tropical rain forest.

Dominance hierarchy and social grooming in female lion-tailed macaques (Macaca silenus) in the Western Ghats, India.

This article reports the structure of dominance and its relationship with social grooming in wild lion-tailed macaque females. The strength of dominance hierarchy was 0.79 on a scale of 0 to 1 indicating a moderate linearity in the ranking system. Dominance scores were converted into an ordinal as well as an interval scale. Grooming scores were also converted into interval scales using standard scores. Grooming received and grooming given correlated positively and negatively respectively with dominance ranks indicating that high ranking females received more and gave less grooming. Grooming was also positively related to encounter rates for dyads of females. More grooming among adjacent ranks, and grooming being more reciprocal, occurred only in the case of dominant females. The grooming patterns, therefore, appeared to be more of despotic than egalitarian nature. While ranking macaques into different Grades of social systems ranging from despotic to egalitarian, Thierry (2004) has placed lion-tailed macaques in Grade 3 corresponding to the 'relaxed' social system. Our results indicate that the grooming and dominance relationships in this species are more despotic, and hence, the Grade for this species requires to be shifted toward 2 or 1.

Comparative analysis of Papaver somniferum genotypes having contrasting latex and alkaloid profiles.

Papaver somniferum produces therapeutically useful benzylisoquinoline alkaloids (BIAs) like papaverine, thebaine, codeine, and morphine that accumulate in its capsular latex. Morphine is a potent analgesic but is also abused as a narcotic, which has increased the demand for non-narcotic thebaine that can be converted into various analgesics. To curtail the narcotic menace, many distinct genotypes of the plant have been developed that are deficient in morphine and/or latex. Sujata is one such latex-less low alkaloid-producing variety developed from the alkaloid-rich gum harvest variety Sampada. Its utility for gene prospecting and studying differential gene regulation responsible for its low alkaloid, nutritive seed oil, and latex-less phenotype has been exploited in this study. BIA profiling of Sujata and Sampada capsules at the early and late stages indicated that except for thebaine, Sujata had a depressed alkaloid phenotype as compared to Sampada. Comparative transcript-based analysis of the two genotypes was carried out in the early stage capsule (higher thebaine) using subtractive hybridization and microarray. Interrogation of a P. somniferum array yielded many differentially expressing transcripts. Their homology-based annotation classified them into categories--latex related, oil/lipid related, alkaloid related, cell wall related, and others. These leads will be useful to characterize the highly sought after Sujata phenotype.

Drastic population decline and conservation prospects of roadside dark-bellied bonnet macaques (Macaca radiata radiata) of southern India.

We carried out a survey on roadside dark-bellied bonnet macaques (Macaca radiata radiata) on the highways around the south Indian city of Mysore. The present survey was the fourth since 1989 on the same populations. We divided the habitats into intensive cultivation (IC), wet cultivation (WC), and scrub forests (SC). The number of groups has significantly reduced from 54 to 31 and the number of animals has declined from 1,207 to 697 from 1989 to 2009. This decline has been recorded only in the IC and WC areas, whereas the population in SC with places of Hindu worship has remained stable. Due to the loss of roadside Ficus trees over the years, the habitat of the monkeys has almost disappeared. Since bonnet macaque is not primarily a forest-dwelling species, the seemingly widespread primate may soon become 'threatened' if the non-forest populations continue to decline. Scrub forests in small hillocks housing Hindu temples remain the only prospective places for conservation of bonnet macaques.

Population dynamics of a group of lion-tailed macaques (Macaca silenus) inhabiting a rainforest fragment in the Western Ghats, India.

We observed the overall population dynamics and number of births and deaths in identified individuals between January 2002 and October 2005, in a large group of lion-tailed macaques in the Anaimalai Hills of the Western Ghats in the south Indian state of Tamilnadu. The group inhabited an isolated rainforest fragment located inside a private tea/coffee garden. The group size increased from 56 in January 2002 to 84 in October 2005. All females reproduced, and the interbirth interval was 23.18 months. Of the 37 infants born between 2002 and 2005, only 1 died providing an infant survivorship rate of about 97.3%. Although births occurred in all months, most of the infants were born between February and March, and this pattern of births was consistent over the years, indicating a major birth peak in this species. The population growth rate in this unusually large group was found to be higher than even in those groups of lion-tailed macaques that inhabit large and relatively undisturbed rainforest complexes. This high growth rate could be attributed to the availability of abundant cultivated fruit plants including commercial crops such as coffee seeds. The observations provide a perspective for the management of other groups of this endangered species inhabiting rainforest fragments.

Distribution, population structure, and conservation of lion-tailed macaques (Macaca silenus) in the Anaimalai Hills, Western Ghats, India.

The lion-tailed macaque is an endangered species, and hence it is necessary that the remaining populations in the rainforests of the Western Ghats, India, be located and their habitats assessed for effective conservation. The Anaimalai Hills in the state of Tamil Nadu harbor 31 groups of lion-tailed macaques. However, the rainforest in these hills is highly fragmented. Since lion-tailed macaques are typically arboreal, the groups have become isolated. Two large rain-forest complexes in these hills harbor 12 and seven groups, respectively, and the remaining 12 groups inhabit small, isolated forest fragments. Group size ranges from six to 53 individuals, with a mean size of 16.3. In the small forest fragments, the standard deviation (SD) of group size was considerably higher than it was in the larger forest complexes. The disturbed fragments also had a higher variability in group size than the relatively undisturbed habitats. It is believed that fragmentation may impede male migration. We suggest that the fragments be managed in such a way that male migration among groups can be facilitated to overcome the potential effects of isolation.