Keyword: Alouatta caraya

Effects of sex, seed size and amount of dietary fiber on retention time of captive black howler monkeys

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The effectiveness of a seed disperser depends, among various factors still poorly understood for many Neotropical primates, on the amount of time seeds are retained within its digestive tract. This study tested the effects of sex, seed size and dietary fiber content on seed retention time in the digestive tract of black howler monkeys (Alouatta caraya). Experiments were performed using six captive individuals (three of each sex), six seed species distributed in three size classes (small, medium, and large), and three percentages of leaves in the diet (15, 30 and 60% of total food ingested). Retention times were recorded for 1767 recovered seeds, corresponding to 55% of the total ingested. More than 98% of these seeds were undamaged, suggesting the potential role of howlers as seed dispersers. Sex, seed size and dietary fiber content alone showed no effect on retention time, but the interaction between sex and seed size showed an effect on the mean retention time, which tended to decrease for males and increase for females as the seed size increased. Thus, males and females may have complementary influences on recruitment and dispersion patterns for different plant species, contributing to community diversity.

Efeito do sexo, do tamanho de sementes e da quantidade de fibra na dieta sobre o tempo de retenção em guariba-preto. A efetividade de um dispersor de sementes depende, dentre outros fatores ainda pouco compreendidos em relação a muitos primatas neotropicais, do tempo em que as sementes são mantidas no trato digestivo do animal. Este estudo testou o efeito do sexo, tamanho da semente e teor de fibra alimentar sobre o tempo de retenção de sementes no trato digestivo de bugios pretos (Alouatta caraya). As sessões experimentais foram realizadas com seis indivíduos cativos (três de cada sexo), seis espécies de sementes distribuídas em três classes de tamanho (pequenas, médias e grandes) e três porções de folhas na dieta (15, 30 e 60% do alimento total ingerido). Os tempos de retenção foram registrados em 1767 sementes recuperadas, correspondendo a 55% do total ingerido. Mais de 98% dessas sementes foram defecadas intactas, sugerindo o potencial dos bugios como dispersores de sementes. O sexo, o tamanho da semente e o teor de fibras alimentares não apresentaram efeito sobre o tempo de retenção, mas a interação entre sexo e tamanho da semente mostrou um efeito sobre a média do tempo de retenção, com tendência a diminuir para machos e aumentar para fêmeas à medida que o tamanho da semente aumenta. Deste modo, machos e fêmeas podem ter influências complementares nos padrões de recrutamento e dispersão para diferentes espécies de plantas, contribuindo para a diversidade da comunidade.

Intestinal parasites of Alouatta caraya (Primates, Ceboidea): preliminary study in semi-captivity and in the wild in Argentina

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Endoparasitic infections are common in nonhuman primates and important factors in regulating their natural populations. Primates are particularly vulnerable to the infections of directly transmitted parasites because they often live in close social groups that facilitate their transmission. The main objective of this study was to provide baseline data on gastrointestinal parasites of semi captive and wild howler monkeys Alouatta caraya troops from Argentina. We collected 110 fecal samples from 38 howler monkeys from four troops, two of them kept in semi-captivity at the CRMAN, Córdoba, and two wild troops from Las Lomas, Corrientes. We identified six species of parasites: four Protozoa, Giardia lamblia, Blastocystis hominis, Eimeria sp. and Entamoeba coli; one Cestoda, Bertiella mucronata and one Nematoda, Strongyloides sp. Of the individuals sampled, 86.8% harbored at least one type of gastrointestinal parasite. Protozoa were found in 78.9% of hosts and helminths in 21.1%. We found significant differences in the prevalence of three protozoan species between study sites; and howlers from Las Lomas showed the highest prevalence. The differences found may be related to environmental conditions, where warmer and wetter regions (Las Lomas) favor the survival of infectious stages of some parasitic species.

Parásitos intestinales de Alouatta caraya (Primates, Ceboidea): estudio preliminar en semi cautiverio y en vida silvestre en la Argentina. Las infecciones endoparasíticas son frecuentes en los primates no humanos y factores importantes que regulan sus poblaciones naturales. Los primates son particularmente vulnerables a las infecciones por parásitos de transmisión directa debido a que usualmente estos viven en grupos sociales que facilitan su transmisión. El principal objetivo del presente estudio fue proveer información de los parásitos gastrointestinales que albergan tropas de monos aulladores Alouatta caraya en semi-cautiverio y en vida silvestre en Argentina. Colectamos 110 muestras de materia fecal de 38 monos aulladores pertenecientes a cuatro tropas, dos de ellas mantenidas en semicautiverio en el CRMAN, Córdoba y dos tropas silvestres en campo Las Lomas, Corrientes. Identificamos seis especies de parásitos: cuatro protozoos, Giardia lamblia, Blastocystis hominis, Eimeria sp. y Entamoeba coli; un cestode, Bertiella mucronata y un nematode, Strongyloides sp. El 86.8% de los individuos muestreados presentaron al menos un tipo de parásito gastrointestinal. Se encontraron protozoos en el 78.9% de los animales y helmintos en el 21.1%. Hallamos diferencias significativas en la prevalencia de tres especies de protozoos entre los sitios de estudio, donde los aulladores de Las Lomas mostraron la mayor prevalencia. Las diferencias encontradas pueden estar relacionadas con las condiciones ambientales, donde regiones más cálidas y húmedas (Las Lomas), favorecen la supervivencia de estadios infecciosos de algunas especies de parásitos.

Adoption of an orphan infant in wild black and gold howler monkeys (Alouatta caraya)

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This study reports the first case of adoption in a wild group of black and gold howler monkeys (Alouatta caraya). After the death of one adult female with a dependent infant, her daughter with a dependent infant adopted the orphan of similar age of her own infant. We recorded the activity and proximity between the adopter and both infants during two following days. The adoptive female appeared to provide equal treatment toward both infants and the orphan seemed to recognize the female as his mother. This report suggests that adult females of A. caraya can rear two infants at once.

Adopción de un infante huérfano en monos aulladores negros y dorados (Alouatta caraya). En este estudio se cita el primer caso de adopción en un grupo silvestre de monos aulladores negros y dorados (Alouatta caraya). Luego de la muerte de una hembra adulta, su hija adoptó al infante huérfano de similar edad que su propio infante. Durante dos días seguidos registramos la actividad y proximidad de la hembra adoptiva y los dos infantes. La hembra adoptiva expresó igual trato hacia ambos infantes y el infante huérfano parecía reconocer a la hembra como su propia madre. Este estudio sugiere que hembras adultas de A. caraya pueden criar dos infantes a la vez.

Análisis de variabilidad proteica en Alouatta caraya y Cebus apella (Primates: Platyrrhini)

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Se estudió la variabilidad genética de individuos adultos de ambos sexos pertenecientes a dos especies de Platyrrhini. Se analizaron 16 muestras de sangre de Alouatta caraya (ACA) y 12 de Cebus apella paraguayanus (CAP). Se estudiaron 10 sistemas proteicos mediante electroforesis horizontal en geles de poliacrilamida. De 14 loci analizados en A. caraya, solo AMP y TF fueron polimórficos (P = 0.1429; = 0.0359); de los 13 loci estudiados en C. a. paraguayanus, solo ESD fue polimórfico (P = 0.0769; = 0.0062). La distancia genética entre ACA y CAP fue D = 0.5962. Los valores de H y D son discutidos respecto de otros previamente publicados para primates neotropicales.

Protein variability analysis for Alouatta caraya and Cebus apella (Primates: Platyrrhini). The genetic variability of adult individuals of both sexes belonging to two species of Platyrrhini was studied. Sixteen blood samples of Alouatta caraya (ACA) and 12 of Cebus apella paraguayanus (CAP) were analyzed. Ten protein systems were examined by horizontal polyacrilamide gel electrophoresis. Out of 14 loci scored in ACA, only AMP and TF were polymorphic (P = 0.1429; = 0.0359), whereas only ESD was polymorphic in 13 loci studied in CAP (P = 0.0769; = 0.0062). The genetic distance between ACA y CAP was D = 0.5962. Values of H and D are discussed with respect to previous published data on Neotropical primates.