Introduction

Project goals

1. Evaluating the physical health status and disease exposure of the howling monkeys on the island of Ometepe;
2. Tagging and marking the animals for long-term follow-up and behavioral studies;
3. Obtaining blood samples for analysis of DNA in order to a. Evaluate intragroup heterogeneity b. Evaluate intergroup heterogeneity (long term goal).

Materials and Methods

The majority of the adults from this monkey group as well as one subadult (N=11, all five adult males, five adult females) were captured using the Pneudart) system with Telazol) as the capture drug (per Glander et al., 1991) over a six day period in late July, 1998 (see Peter et al. 1999, elsewhere in this symposium for details). Blood was drawn from the femoral vein after which each animal was marked with color-coded collars (E) or ankle bands (G) and ear tags before release (Table 1). DNA was extracted from the blood, isolated and frozen prior to analysis. PCR techniques were utilized to examine 11 microsatellite loci, which had been previously identified for Alouatta palliata and Saimiri (Ellsworth and Hoelzer 1998, Witte and Rogers 1999). We successfully amplified 10 of these loci (see Figure 1) using the following PCR conditions : DNA 40-80ng, dNTP 100 mM, MgCl2 1.5 mM, KCl 50mM, Tris 10mM, Triton 100 0.1%, Primer 0.2 mM, Taq Polymerase 0.5 mM. One primer was radiolabeled with 8-32p using T4 polynucleotide kinase.

Thermal cycle routines were as follows:
1 cycle 5 min @ 95: C
35 cycles 1 min @ 95: C
1 min @ 55: C
1 min @ 72: C
1 cycle 5 min @ 72: C

Results

Although the monkeys within our group are monomorphic and homozygous for 5 of the microsatellite loci, they are polymorphic for the rest. Forty-four % of the alleles were heterozygous from the polymorphic microsatellite loci.

Discussion

We did find less allelic variation than reported in howling monkeys elsewhere in Central America (Table 2). But as discussed above, that may be indicative of differences in geographic sampling. It remains unclear whether our small sample is representative of all howling monkeys on the island.

Conservation genetics has generally focused on maintaining overall levels of genetic variation (Hoffman and Parsons, 1991). Genetic variation is important in preserving allelic variants, which may facilitate individual response to severe or prolonged environmental stressors. Overall, genetic variability is dependent on the size and number of animals, intergroup variability of fragmented populations, the degree of fragmentation, and whether fragmentation limits intergroup migration. It is unclear how much the fragmentation which has occurred on Ometepe limits gene flow or overall variability. And as Pope has pointed out, intergroup variability may still exist therefore genetic differences between groups may still be higher than continuous populations.

Conclusions

We would like to thank Rex Sohn and Greg Peter for their collaboration in the field portion of this research (Figure. 5). Their skill, field expertise, and equanimity were critical and much appreciated. And our many thanks to the students and teaching assistants of the advanced primate behavior and biology class (Figure. 5) who served as field assistants, shared their ideas, and in some cases, their photographs. A special thanks you to Toran Hanson who so generously shared his howling monkey photographs. We thank and acknowledge the government of Nicaragua who gave us permission to do this research. And our bounteous gratitude to the Ometepe Biological Field Station, its staff, and the wonderful Molina family who is always hospitable and has offered their support in countless ways. We gratefully acknowledge support from the University of Pittsburgh and Parke-Davis Research.

TABLE 1: Animals captured and sampled during darting project

3 unmarked adult females
one with infant/juvenile (dorsal)
one with older juvenile
one with no offspring
one subadult/young adult, stayed on fringe of group

Total group composition
5 adult Male
8 adult Female
2 subadult (possibly 3)
6 infant/juveniles

TABLE 2: A COMPARISON OF ALLELE NUMBER FOR TEN MICROSATELLITE LOCI IN ALOUATTA PALLIATA ON OMETEPE AND ELSEWHERE IN CENTRAL AMERICA

1) Data from Witte and Rogers, 1999 and Ellsworth and Hoelzer, 1998
2) Data from Ellsworth and Hoelzer, 1998, Sample size=10

Bibliography

Crockett C. M.1998. Conservation biology of the genus Alouatta. International Journal of Primatology 19:549-578.

Ellsworth J. and G. Hoelzer 1998. Characterization of microsatellite loci in a New World primate, the mantled howling monkeys (Alouatta palliata). Molecular Ecology 7:657-658.

Glander K.E. 1992. Dispersal patterns in Costa Rican mantled howling monkeys. International Journal of Primatology 13:415-436.

Glander K. E., L. M. Fedigan, and L. Fedigan 1991. Field methods for capture and measurement of three monkey species in Costa Rica. Folia Primatologica 57: 70-82.

Hoffman A.A. and P.A. Parsons 1991. Evolutionary Genetics and Environmental Stress, Oxford University Press, Oxford.

Malmgren L.A. and A.H. Brush 1978. Isozymes and plasma proteins in eight troops of golden mantled howling monkeys (Alouatta palliata). In Chivers, D and Joysey K (eds.) Recent Advances in Primatology Volume III: Evolution, Academic Press pp 283-285.

Peter G., R. Sohn, and L. Winkler 1999. Capture, health, and morphological assess,emt of free-ranging mantled howling monkeys (Alouatta palliata) in Nicaragua. American Journal of Physical Anthropology Supplement 28: 221.

Pope T. R.1995. Socioecology, population fragmentation, and patterns of genetic loss in endangered primates. In Avise, J and Hamrick, J (eds.) Conservation Genetics: case Histories from Nature, Chapman and Hall pp 119-159.

Witte S. M. and J. Rogers 1999. Microsatellite polymorphisms in Bolivian Squirrel Monkeys (Saimiri boliviensis). American Journal of Primatology 46: 75-84.

Dr. Linda Winkler, Associate Professor Biological Sciences and Anthropology
University of Pittsburgh, Titusville
PO Box 287
Titusville, PA 16354
1-814-827-4436