A population of black and gold howler monkeys (Alouatta caraya) living near the southern limit of its distribution in a semideciduous forest located in northern Argentina was studied in 2003 to evaluate the possible effects of habitat fragmentation - owing to logging - on its density and social organization within it. Aerial photographs taken in 1982, 1992, and 2001 were used to compare maps of vegetation. These maps were used to evaluate changes in the area covered by forest fragments. From March to June 2003, 10-day monthly surveys of howlers were made in each fragment. A total of 232 individual howlers were counted, belonging to 34 groups plus a solitary adult female. Groups ranged from 2 to 19 individuals (mean = 6.82, SD = 4.23), and 21% of the groups contained more than one adult male. Adults accounted for 55% of the individuals, immatures for 45%, and infants represented 13% of the total. Data obtained were compared with information available for the same population for 1982 and 1995. Results revealed no significant changes in the area of fragments, the crude and ecological density of howlers, and group composition. Group sizes and group composition of howlers suggest that the population remained stable over the past 22 years. The density, number of groups, and individuals appears not to be affected by fragmentation and logging, but crude density was low compared with other less-disturbed habitats. The status of the population remains uncertain owing to isolation, and because there are no protected areas to ensure its stability for the future.

Human-induced habitat fragmentation might seriously affect behavioural patterns and the survival of species whose ecological requirements strongly depend on specific environmental conditions. We compared the genetic structure and dispersal patterns of 2 populations of Alouatta caraya (Plathyrrhini, Atelidae) to understand how habitat reduction and fragmentation affect gene flow in this species. We sampled individuals from 7 groups living in continuous forest (CF, n=46, 22 males and 24 females), and 11 groups that inhabit a fragmented forest (FF, n=50, 24 males and 26 females). FST values based on 11 microsatellite loci showed a recent genetic differentiation among groups in the FF. In contrast, the CF showed no differentiation among groups. Further, FST values between sexes, as well as kinship relationships, also exhibited differences between habitats. In the CF, both males and females disperse, leading to nondifferentiated groups composed of adults that are not close relatives. Conversely, in the FF, some groups are differentiated, males disperse more than females, and groups are composed of closely related adult females. Our results suggest that habitat fragmentation modifies the dispersal patterns of black-and-gold howlers. These differences between habitats may reflect a reduced gene flow, providing genetic evidence that suggests that habitat fragmentation severely limits the howler's ability to disperse. An increasing level of isolation due to uncontrolled deforestation may cause similar loss of genetic diversity on other arboreal primates, and nonprimates that depend on Int J Primatol (2010) 31:813-832

No abstract

Several medically important mosquito-borne flaviviruses have been detected in Argentina in recent years: Dengue (DENV), St. Louis encephalitis (SLEV), West Nile (WNV) and Yellow Fever (YFV) viruses. Evidence of Bussuquara virus (BSQV) and Ilheus virus (ILHV) activity were found, but they have not been associated with human disease. Non-human primates can act as important hosts in the natural cycle of flaviviruses and serological studies can lead to improved understanding of virus circulation dynamics and host susceptibility. From July–August 2010, we conducted serological and molecular surveys in free–ranging black howlers (Alouatta caraya) captured in northeastern Argentina. We used 90% plaque-reduction neutralization tests (PRNT90) to analyze 108 serum samples for antibodies to WNV, SLEV, YFV, DENV (serotypes 1and 3), ILHV, and BSQV. Virus genome detection was performed using generic reverse transcription (RT)-nested PCR to identify flaviviruses in 51 antibody-negative animals. Seventy animals had antibodies for one or more flaviviruses for a total antibody prevalence of 64.8% (70/108). Monotypic (13/70, 19%) and heterotypic (27/70, 39%) patterns were differentiated. Specific neutralizing antibodies against WNV, SLEV, DENV-1, DENV-3, ILHV, and BSQV were found. Unexpectedly, the highest flavivirus antibody prevalence detected was to WNV with 9 (8.33%) monotypic responses. All samples tested by (RT)-nested PCR were negative for viral genome. This is the first detection of WNV-specific antibodies in black howlers from Argentina and the first report in free-ranging non-human primates from Latin-American countries. Given that no animals had specific neutralizing antibodies to YFV, our results suggest that the study population remains susceptible to YFV. Monitoring of these agents should be strengthened to detect the establishment of sylvatic cycles of flaviviruses in America and evaluate risks to wildlife and human health.