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Borries C, Lu A, Ossi-Lupo K, Koenig A. Timing of conceptions in Phayre's leaf monkeys: Energy and phytochemical intake. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24881. [PMID: 38018374 DOI: 10.1002/ajpa.24881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 09/21/2023] [Accepted: 11/03/2023] [Indexed: 11/30/2023]
Abstract
OBJECTIVES Raising offspring imposes energetic costs, especially for female mammals. Consequently, seasons favoring high energy intake and sustained positive energy balance often result in a conception peak. Factors that may weaken this coordinated effect include premature offspring loss and adolescent subfertility. Furthermore, seasonal ingestion of phytochemicals may facilitate conception peaks. We examined these factors and potential benefits of a conception peak (infant survival and interbirth interval) in Phayre's leaf monkeys (Trachypithecus phayrei crepusculus). MATERIALS AND METHODS Data were collected at Phu Khieo Wildlife Sanctuary, Thailand (78 conceptions). We estimated periods of high energy intake based on fruit and young leaf feeding and via monthly energy intake rates. Phytochemical intake was based on fecal progestin. We examined seasonality (circular statistics and cox proportional hazard models) and compared consequences of timing (infant survival and interbirth intervals, t-test, and Fisher exact test). RESULTS Conceptions occurred in all months but peaked from May to August. This peak coincided with high fecal progestin rather than presumed positive energy balance. Primipara conceived significantly later than multipara. Neither infant survival nor interbirth intervals were related to the timing of conception. DISCUSSION Periods of high energy intake may not exist and would not explain the conception peak in this population. However, the presumed high intake of phytochemicals was tightly linked to the conception peak. Timing conceptions to the peak season did not provide benefits, suggesting that the clustering of conceptions may be a mere by-product of phytochemical intake. To confirm this conclusion, seasonal changes in phytochemical intake and hormone levels need to be studied more directly.
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Affiliation(s)
- Carola Borries
- Department of Anthropology, Stony Brook University, SUNY, Stony Brook, New York, USA
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SUNY, Stony Brook, New York, USA
| | - Amy Lu
- Department of Anthropology, Stony Brook University, SUNY, Stony Brook, New York, USA
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SUNY, Stony Brook, New York, USA
| | - Kerry Ossi-Lupo
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SUNY, Stony Brook, New York, USA
| | - Andreas Koenig
- Department of Anthropology, Stony Brook University, SUNY, Stony Brook, New York, USA
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SUNY, Stony Brook, New York, USA
- Graduate Program in Ecology and Evolution, Stony Brook University, SUNY, Stony Brook, New York, USA
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L'Allier S, Schwegel MA, Filazzola A, Mastromonaco G, Chapman CA, Schoof VAM. How individual, social, and ecological conditions influence dispersal decisions in male vervet monkeys. Am J Primatol 2022; 84:e23426. [PMID: 35942562 DOI: 10.1002/ajp.23426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 01/09/2023]
Abstract
Dispersal between social groups reduces the risk of inbreeding and can improve individuals' reproductive opportunities. However, this movement has costs, such as increased risk of predation and starvation, loss of allies and kin support, and increased aggression associated with entering the new group. Dispersal strategies, such as the timing of movement and decisions on whether to transfer alone or in parallel with a peer, involve different costs and benefits. We used demographic, behavioral, hormonal, and ecological data to examine the causes and consequences of 36 dispersal events from 29 male vervet monkeys (Chlorocebus pygerythrus) at Lake Nabugabo, Uganda. Adult males' secondary dispersal coincided with the conception season in females, and males improved their potential access to females by moving to groups with higher female-to-male sex ratios and/or by increasing their dominance rank. Males that dispersed with a peer had lower fecal glucocorticoid and androgen metabolite levels than lone dispersers. Subadult males were not more likely to engage in parallel dispersals compared to adult males. Dispersal was also used as a mechanism to avoid inbreeding, but changes in hormone levels did not seem to be a trigger of dispersal in our population. Our findings illustrate the complex individual strategies used during dispersal, how many factors can influence movement decisions, as well as the value of dominance and hormone analyses for understanding these strategies.
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Affiliation(s)
- Simon L'Allier
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Megan A Schwegel
- Department of Biology, York University, Toronto, Ontario, Canada.,Department of Multidisciplinary Studies, Glendon campus, Bilingual Biology Program, York University, Toronto, Ontario, Canada
| | - Alessandro Filazzola
- Department of Biology, York University, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | | | - Colin A Chapman
- Biology Department, Vancouver Island University, Nanaimo, British Columbia, Canada.,Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington DC, USA.,School of Life Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa.,Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, China
| | - Valérie A M Schoof
- Department of Biology, York University, Toronto, Ontario, Canada.,Department of Multidisciplinary Studies, Glendon campus, Bilingual Biology Program, York University, Toronto, Ontario, Canada
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