Genetic structure of three populations of rhesus macaques (Macaca mulatta): Implications for genetic management

One of the prime concerns at zoos and at primate breeding facilities is to maintain genetic variability. This can be accomplished by avoiding inbreeding. It is relatively easy to assess genetic variability and the level of inbreeding by using pedigree information and genetic markers. In this study we used genetic markers controlled by 6 independent polymorphic loci (GPI, PGD, CA2, MPI, DIA1, Tf) to ascertain genetic variation in two captive and one wild population of rhesus monkeys. Two other loci ADA and NP were also examined and found to be monomorphic in the three populations. F-statistics and contingency chi-square analyses indicated that there was significant genetic differentiation among the populations. We also found that the mean heterozygosities were very similar in the three populations, in spite of the diverse breeding strategies. These data are important because rhesus monkeys are frequently used for biomedical research; and the genetic markers provide useful information for genetic management of captive colonies of nonhuman primates. © 1992 Wiley-Liss, Inc.     

Brief report: Infant-killing and infant disappearance following male takeovers in a group of free-ranging howling monkeys (Alouatta palliata) in Costa Rica

Events surrounding an infant-killing following a male takeover are described for a group of free-ranging howling monkeys in Costa Rica, and additional evidence is presented for infant disappearances following three previous male takeovers. Infant-killing is best interpreted in this context as a male reproductive strategy, as infant-killing did effectively shorten the interbirth interval, and only infants of high-ranking females died or disappeared following a male takeover. Due to the exclusive access of the dominant male to high-ranking estrous females, an incoming male who had lived as a peripheral male before taking over the group would run little risk of eliminating his own offspring in the course of killing the offspring of high-ranking females.     

Comparison of frugivory by howling monkeys (Alouatta palliata) and bats (Artibeus jamaicensis) in the tropical rain forest of Los Tuxtlas,Mexico

Information on the fruit diets of howling monkeys and fruit-eating bats in the tropical rain forest of Los Tuxtlas, Mexico was collected for a year to compare the plant species used. Howling monkeys used 19 plant species whereas bats used 32 plant species as fruit sources. Eleven species were common in the diet of both mammals. A rank analysis at the plant species level showed that the fruit diets of Alouatta and Artibeus were very different. In contrast to bats, howling monkeys displayed a seasonal pattern in fruit consumption. Diet overlap between the two mammals was highest during the monkeys' fruit-eating season. Measures of fruit production in eight trees (four species) indicated marked variations in fruit biomass produced and in length of fruiting from tree to tree and species to species. Peaks in fruit production were typical both at the species and the individual tree levels, demonstrating the very patchy nature of the fruit available to the monkeys and the bats.     

Fear responses of Japanese monkeys to scale models

This study investigated fear responses of Japanese monkeys (Macaca fuscata) to scale models. Fear responses of participants were assessed using rating scores assigned by judges. In Experiment 1, participants were presented with scale models of objects in furniture, vehicle, and mammal categories. Overall, the participants expressed stronger fear responses to mammal objects as compared to the other two kinds. In Experiment 2, participants were presented with scale models of furniture, new mammals, and animals composed of insects, birds, fish, and reptiles. As a whole, the participants showed stronger fear responses to the new mammal and animal objects than to furniture objects. Fear responses to mammal and animal objects were comparable. These results suggest that Japanese monkeys show stronger fear responses to objects possessing perceptual properties of animals, as opposed to objects that do not possess such properties.     

The Role of Minerals in Food Selection in a Black Howler Monkey (Alouatta Pigra) Population in Belize Following a Major Hurricane

As plants may contain low levels of some minerals including sodium, copper, and phosphorous, herbivores may become deficient in these nutrients. In 2001, Hurricane Iris hit the Monkey River Forest in Belize causing substantial damage to the food supply of the black howler monkey population (Alouatta pigra) living there. This included an 18‐month absence in fruit production and a complete loss of figs that are high in calcium. In this article, we describe the post‐hurricane diet of this monkey population and compare the mineral content of food items to each other and to recommendations for non‐human primates [NRC 2003]. We also investigate food selection in relation to potentially limiting minerals. Behavioral data from four groups of howlers (2002–2006) and samples of all ingested food items were collected and a sample of 99 plant from 18 food species was analyzed for mineral content. Unexpectedly, the post‐hurricane diet contained more mature leaves than new leaves despite the availability of new leaves. Leaves contained higher amounts of minerals than reproductive parts and with the exception of Cecropia peltata stems, plant parts were low in sodium. Cecropia peltata is a pioneer species that grows following habitat disturbance thus the ingestion of these stems may be a potential mechanism to avoid sodium deficiency in this damaged forest. Calcium and zinc were found above recommended values in most food items; however, both positively predicted food selection, which may reflect a difference between their abundance and their bioavailability. However, as mature leaves contained more calcium than other plant parts, their high post‐hurricane consumption may also be a response to the absence of figs and the need to find an alternate calcium source. This study highlights how habitat disturbance may affect mineral abundance and the dietary choices of primates. Am. J. Primatol. 74:1054‐1063, 2012. © 2012 Wiley Periodicals, Inc.     

A microagglutination test for blood typing rhesus monkeys, Macaca mulatta

Summary. We have developed a microagglutination test for typing rhesus monkey erythrocytes that is sensitive, accurate and easy to perform. The technique requires only μ1 quantities of antiserum and cells, and agglutination is easily detected using an inverted microscope. An advantage of this technique is that the typing plates can be stored at -70°C without loss of activity. The results of typing over 400 rhesus blood samples with this technique were 95% concordant with results using the standard microtitre agglutination technique. Preliminary results indicate that this test is also adaptable to typing human blood.     

Platyrrhine color signals: New horizons to pursue

Like catarrhines, some platyrrhines show exposed and reddish skin, raising the possibility that reddish signals have evolved convergently. This variation in skin exposure and color combined with sex‐linked polymorphic color vision in platyrrhines presents a unique, and yet underexplored, opportunity to investigate the relative importance of chromatic versus achromatic signals, the influence of color perception on signal evolution, and to understand primate communication broadly. By coding the facial skin exposure and color of 96 platyrrhines, 28 catarrhines, 7 strepsirrhines, 1 tarsiiform, and 13 nonprimates, and by simulating the ancestral character states for these traits, we provide the first analysis of the distribution and evolution of facial skin exposure and color in platyrrhini. We highlight ways in which studying the presence and use of color signals by platyrrhines and other primates will enhance our understanding of the evolution of color signals, and the forces shaping color vision.     

Pronymphs,hatching, and proboscis assembly in leafhoppers and froghoppers (Hemiptera,Cicadellidae and Aphrophoridae)

Pharate 1st instar nymphs enclosed in the embryonic cuticle, referred to as pronymphs, were studied in a froghopper Aphrophora pectoralis Mats. (Aphrophoridae) and the leafhoppers Oncopsis flavicollis (L.), Populicerus populi (L.), Alebra wahlbergi (Boh.), Igutettix oculatus (Lindb.), and Scenergates viridis (Vilb.) (Cicadellidae). The species vary in the relative length of the pronymphal antennae and details of sculpturing of the cephalic region. No egg bursting structures were observed, except small denticles on the crown region of S. viridis pronymphs. Rudimentary mandibular and maxillary stylets of a pronymph are external, short, tubular appendages containing tips of the corresponding nymphal stylets, whose more basal parts develop inside of the head. Casting off of the embryonic cuticle results in the nymphal stylets being passively pulled out and assuming a close-set parallel orientation. Once the sheaths of unsclerotized cuticle secreted by the peripodial epithelium and enveloping each developing stylet have been cast off with the exuviae, the bare stylets become squeezed and interlocked into a functional bundle. The roles of the maxillary plates, clypeus, labrum, and labium in the stylet bundle assembly are discussed. The process repeats after each molt.     

Browridge development in cercopithecidae: A test of two models

Theoretical discussions of primate browridge formation have resulted in several interpretations of its form and function. Lateral radiographs of adult Old World monkeys, representing most cercopithecine and colobine genera, were examined to address whether both biomechanical and spatial factors influence the development of a supraorbital torus. A linear measurement of browridge size was compared with a series of measures related to each model. Partial correlations were used to ascertain the relative independence of biomechanical (model I or II) and spatial effects upon torus formation. Allometric (size-related) shape changes were evaluated with log-linear bivariate regression analysis; subfamily differences in scaling patterns, with an analysis of covariance. When spatial and biomechanical (I or II) factors were both significantly related to brow size, additive and interactive multiple regression models were used to further assess the manner by which each set mutually affects variation in browridge dimensions. Correlation analyses were repeated with size-corrected antilogged residuals to eliminate a potentially spurious effect of skull size. Old World monkeys provide support of the spatial model. Also of interest is that skull size emerges as a primary influence on torus formation. Several alternative explanations are also put forward to account for browridge development in each subfamily.