An official website of the United States government
Abstract ObjectivesWe quantified variation in fecal cortisol across reproductive periods in Azara's owl monkeys (Aotus azarae) to examine physiological mechanisms that may facilitate biparental care. Specifically, we evaluated evidence for the explanation that owl monkeys have hormonal mechanisms to mobilize energy during periods when each sex is investing heavily in reproduction, that is, the gestation period for females and the infant care period for males. Materials and methodsBetween 2011 and 2015, we monitored 10 groups of Azara's owl monkeys from a wild population in Formosa, Argentina and collected fecal samples from 26 adults (13 males, 13 females). Using enzyme‐linked immunosorbent assays, we quantified fecal cortisol as a proxy for evaluating stress responses, including energetic demands, on both sexes during periods of reproduction and parental care. ResultsMale cortisol was lowest during periods when they were caring for young infants (<3 months) compared with periods with older infants or no infant. Female cortisol was elevated during gestation compared with other periods. Mean fecal cortisol in both males and females was lower when an infant was present compared with when females were gestating. DiscussionOur results do not support the hypothesis that owl monkey males have elevated fecal cortisol during periods when they need to mobilize energy to provide intensive infant care. Our findings are also inconsistent with the Maternal Relief hypothesis. However, results from studies measuring fecal cortisol must be interpreted with care and alternative explanations, such as seasonal fluctuations in diet and thermoenergic demands, should be considered when drawing conclusions.
more »
« less
The socioecology of parasite infection in wild Bornean orangutans (Pongo pygmaeus wurmbii) in Gunung Palung National Park, West Kalimantan, Indonesia
The socioecological model predicts that food availability and risk of parasite transmission influence sociality in primates. As a semi-solitary ape inhabiting the masting forests of Southeast Asia, orangutans provide a unique opportunity to compare social and non-social periods and highly variable foraging conditions within one population. This study compared two data collection periods when fruit availability differed markedly to determine whether sociality and parasite prevalence decrease as expected during periods of fruit scarcity. Fecal samples were analyzed using direct smear and fecal concentration techniques on-site at Cabang Panti Research Station from 2013-2014 and 2018-2019. From the high fruit period to the low fruit period, sociality decreased from 54% of focal follows containing a social event to 29%, while overall parasite prevalence remained the same at 100%. Interesting differences arose for certain parasite species, however. Enterobius sp. prevalence decreased during the low fruit period for both sexes but even more so for males (50% to 29% for females; 56% to 0 for males). Prevalence of Trichuris sp. increased for females during the low fruit period (5% to 43%) while prevalence among males remained the same. These results lend support to the prediction that social contact influences transmission risk for some parasite species, while other parasites may be more responsive to factors such as changes in reproductive state. These findings suggest that differences in the behavioral strategies of the sexes and the differential energetic demands of life history stages have an influence on parasitic infection patterns.
more »
« less
- PAR ID:
- 10186253
- Date Published:
- Journal Name:
- American journal of physical anthropology
- Volume:
- 171
- Issue:
- Supplement 69
- ISSN:
- 0002-9483
- Page Range / eLocation ID:
- 203
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)Abstract Pronounced temporal and spatial variation in the availability of food resources can produce energetic deficits in organisms. Fruit-dependent Bornean orangutans face extreme variation in fruit availability and experience negative energy and protein balance during episodes of fruit scarcity. We evaluate the possibility that orangutans of different sexes and ages catabolize muscle tissue when the availability of fruit is low. We assess variation in muscle mass by examining the relationship between urinary creatinine and specific gravity and use the residuals as a non-invasive measure of estimated lean body mass (ELBM). Despite orangutans having a suite of adaptations to buffer them from fruit scarcity and associated caloric deficits, ELBM was lower during low fruit periods in all age-sex classes. As predicted, adult male orangutans had higher ELBM than adult females and immatures. Contrary to expectation, flanged and unflanged males did not differ significantly in ELBM. These findings highlight the precarity of orangutan health in the face of rapid environmental change and add to a growing body of evidence that orangutans are characterized by unique metabolic traits shaped by their unpredictable forest environment.more » « less
-
Barrett, Louise (Ed.)Abstract Direct pathogen and parasite transmission is fundamentally driven by a population’s contact network structure and its demographic composition and is further modulated by pathogen life-history traits. Importantly, populations are most often concurrently exposed to a suite of pathogens, which is rarely investigated, because contact networks are typically inferred from spatial proximity only. Here, we use 5 years of detailed observations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) that distinguish between four different types of social contact. We investigate how demography (sex and age) affects these different social behaviors. Three of the four social behaviors can be used as a proxy for understanding key routes of direct pathogen transmission (sexual contact, skin contact, and aerosol contact of respiratory vapor above the water surface). We quantify the demography-dependent network connectedness, representing the risk of exposure associated with the three pathogen transmission routes, and quantify coexposure risks and relate them to individual sociability. Our results suggest demography-driven disease risk in bottlenose dolphins, with males at greater risk than females, and transmission route-dependent implications for different age classes. We hypothesize that male alliance formation and the divergent reproductive strategies in males and females drive the demography-dependent connectedness and, hence, exposure risk to pathogens. Our study provides evidence for the risk of coexposure to pathogens transmitted along different transmission routes and that they relate to individual sociability. Hence, our results highlight the importance of a multibehavioral approach for a more complete understanding of the overall pathogen transmission risk in animal populations, as well as the cumulative costs of sociality.more » « less
-
As wild orangutan populations become increasingly endangered, knowledge of their physiological and disease status provides critical information on how human disturbances, such as habitat loss, affect their health and long-term viability. An important tool in the assessment and monitoring of orangutan health is the detection of parasites in feces, as parasites can impact a wide range of biological functions. Intestinal parasites place stress on the host system, affecting nutrition, energy expenditure, travel, feeding patterns, immune function, and reproductive success. Thus, the analysis of non-invasively collected fecal samples provides a useful proxy for population health. Forty nine samples from 14 unique individuals were analyzed using both direct smear and single centrifuge flotation techniques. Samples were examined under a microscope and parasites were identified using movement type and morphological characteristics. A 100 percent overall parasite prevalence was found. Species of Balantidium, Entamoeba, Enterobius, Trichuris, Ascaris and Strongyle-type parasites were found. Larvae were also observed in all samples. An independent-samples Mann-Whitney U test found that the distribution of Balantidium sp. and Trichuris sp. were not even, and the prevalence among females was significantly higher. These results were unexpected, as they differ from the findings of prior parasitology studies, which found no difference in parasite prevalence between the sexes. This further emphasizes the need for continuing research as part of a longitudinal study.more » « less
-
As wild orangutan populations become increasingly endangered, knowledge of their physiological and disease status provides critical information on how human disturbances, such as habitat loss, affect their health and long-term viability. An important tool in the assessment and monitoring of orangutan health is the detection of parasites in feces, as parasites can impact a wide range of biological functions. Intestinal parasites place stress on the host system, affecting nutrition, energy expenditure, travel, feeding patterns, immune function, and reproductive success. Thus, the analysis of non-invasively collected fecal samples provides a useful proxy for population health. Forty nine samples from 14 unique individuals were analyzed using both direct smear and single centrifuge flotation techniques. Samples were examined under a microscope and parasites were identified using movement type and morphological characteristics. A 100 percent overall parasite prevalence was found. Species of Balantidium, Entamoeba, Enterobius, Trichuris, Ascaris and Strongyle-type parasites were found. Larvae were also observed in all samples. An independent-samples Mann-Whitney U test found that the distribution of Balantidium sp. and Trichuris sp. were not even, and the prevalence among females was significantly higher. These results were unexpected, as they differ from the findings of prior parasitology studies, which found no difference in parasite prevalence between the sexes. This further emphasizes the need for continuing research as part of a longitudinal study.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
