{"@context":"http://iiif.io/api/presentation/2/context.json","@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/manifest.json","@type":"sc:Manifest","label":"Nutritional Ecology and Growth in Juvenile Phayre's Leaf Monkeys","metadata":[{"label":"dc.description.sponsorship","value":"This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree."},{"label":"dc.format","value":"Monograph"},{"label":"dc.format.medium","value":"Electronic Resource"},{"label":"dc.identifier.uri","value":"http://hdl.handle.net/11401/76977"},{"label":"dc.language.iso","value":"en_US"},{"label":"dc.publisher","value":"The Graduate School, Stony Brook University: Stony Brook, NY."},{"label":"dcterms.abstract","value":"Primates exhibit slow growth and an extended juvenile period relative to other similar-sized mammals. Certain evolutionary explanations have linked the costs or benefits of bigger primate brains to slow life histories in general, although a link specifically to the length of juvenility is less clear. The ecological risk aversion hypothesis singles out the juvenile period as a target of selection, positing that slower growth rates and smaller size provide juveniles with an energetic buffer (i.e., lower absolute metabolic demand) against starvation risk during a critical period of heightened vulnerability. This greater vulnerability is attributed largely to juveniles' lower foraging and competitive abilities, making them more susceptible to nutritional stress, particularly during seasonal shortages in resource availability.       Folivorous primates have been described as having a relatively lower risk of starvation due to their reliance on a seasonally abundant, less contestable resource. In addition, a lower quality, leaf-based diet has less foraging complexity and therefore a lower threshold for skill acquisition. Such arguments, however, do not account for the greater mechanical demands of a folivorous diet. Increased dietary toughness and fiber content pose potential food-processing pitfalls for juveniles, who may be hampered by lesser masticatory strength, smaller gape size, or lack of complete permanent dentition.       This dissertation explored feeding behavior and growth during the juvenile life stage for a folivorous primate, Phayre's leaf monkeys (Trachypithecus phayrei crepusculus), in a seasonal forest at the Phu Khieo Wildlife Sanctuary in Thailand. Between November 2006 and May 2008, I collected data on juvenile, subadult and adult subjects from three habituated groups of Phayre's leaf monkeys to form three main datasets: 1) adult and juvenile feeding behavior data including instantaneous recording of dietary composition and continuous recording, whenever possible, of intake rates (i.e., bites per minute), 2) dietary characteristics, specifically, food plant fracture toughness and nutritional content profiles, and 3) juvenile growth and pseudo-velocity curves of distal lower limb length. I combined these datasets to achieve three main study goals: 1) compare feeding efficiency (i.e., bite rates) across age classes with a specific focus on the effect of dietary toughness, 2) investigate age-related differences in feeding behavior and the consequences for juveniles' nutritional and energetic intake, and 3) characterize juvenile limb growth patterns for a wild colobine species and test for developmental correlates of individual variation in size-for-age. In investigating juvenile feeding ability, I predicted that juveniles - due to size- and strength-related constraints - would be less efficient (i.e., slower bite rates), would be disproportionately negatively affected by food toughness, and thus would consume less-tough foods. Via focal animal and ad libitum sampling, I counted bites (or number of whole items consumed depending on food type) per minute during feeding bouts as the measure of feeding efficiency. While bite rates varied depending on the food being consumed, age also played a significant role: both younger and older juveniles fed significantly more slowly than adults. Similarly, while increasing dietary toughness slowed bite rates for all age classes, younger juveniles but not older juveniles experienced steeper declines in efficiency with tougher foods. Yet, neither younger nor older juveniles eschewed tough foods, consuming diets no different in overall toughness from those of adults based on both dietary composition and feeding times.      Next, to assess whether reduced efficiency led to energetic consequences for juveniles, I compared energy, protein and fiber intake scaled according to metabolic mass for each age class using two datasets: the first, a 7-month dataset encompassing fruiting and flowering peaks was used to compare juveniles to adults, and the second comprised three seasonal blocks across a 17-month span for known-aged immatures (16 to 65 months). I predicted that, in order to meet energetic requirements, juveniles would compensate for reduced efficiency by increasing feeding effort or by altering dietary composition. I also expected that seasonal increases in food processing demand (i.e., dietary toughness and fiber intake) would more severely affect juveniles' energy intake rates. Plants eaten by the monkeys were collected, dried and analyzed for macronutrient content (n = 95 food items). I used these nutritional data to estimate hourly rates of energy and nutrient intake for each focal individual. Juveniles typically had higher rates of energy (kilocalories/hour) and protein consumption (grams (DM)/hr) per unit of metabolic mass than subadults and adults, although age classes did not differ in their fiber intake (NDF grams (DM)/hr). I found no significant age differences in dietary proportions according to food type (i.e., young and mature leaves, seeds, fruits, and flowers). Juveniles ensured adequate intake by spending more time feeding than adults, rather than by consuming higher-quality or less-tough foods.  There was one exception to the pattern: in one month with relatively higher NDF intake, younger juveniles (i.e., those closest to average weaning age) had the lowest nutritional intake rates among all four age classes even controlling for their smaller metabolic mass. However, there was no significant age effect of either fiber intake or dietary toughness on energy and protein intake rates. More specifically, even though younger juvenile feeding efficiency was disproportionately slowed by dietary toughness, these individuals did not show an equivalent proportionally greater increase in feeding time relative to toughness; instead, comparable rises in feeding effort occurred for younger and older subjects alike. Interestingly, NDF intake was the only dietary rate variable to exhibit a decline relative to dietary toughness, although this was likely due to the fact that measures of toughness but not NDF included seed pods and casings that were processed but discarded rather than consumed.       Finally, to describe the patterns of limb length growth for Phayre's leaf monkeys, I employed non-invasive photogrammetric methods to measure distal lower limb lengths for all juvenile subjects and a subset of adults and older infants. Cubic spline regressions were used to fit curves to the limb length data at known ages for males and females as well as individual curves for subjects with longitudinal data (i.e., 5 or more datapoints across a 10-16-month time span). Pseudo-velocity curves depicted a steady decline in growth rate for juvenile females and a more gradual decline for juvenile males, although when plotted individually, males seemed to exhibit a possible acceleration, or growth spurt, right around the start of subadulthood. Although variation in dietary quality has been shown to affect growth rates in other primates, here I found no significant relationship between variation in juvenile growth rates controlling for age and nutritional intake. Yet, longer term growth consequences were apparent: in particular, individuals with later weaning ages had significantly longer length-for-age as older juveniles. This finding contrasts with results from baboon studies, for example, where maternal rank and condition were stronger determinants of female size-for-age, and high-ranking mothers actually were able to wean offspring at earlier ages. Also juvenile females with longer length-for-age showed a trend toward earlier dispersal ages, which may indicate these larger females had or would reach sexual maturity sooner than their smaller counter parts.      Overall, juvenile Phayre's leaf monkeys exhibited reduced bite-rate efficiency, and dietary toughness disproportionately suppressed bite rates for younger juveniles. Yet juveniles did not avoid high-toughness foods, and, relative to metabolic mass, typically managed to maintain nutritional intake rates significantly above those of adults and subadults with one possible exception. They were able to do so largely due to greater feeding effort as well as the metabolic buffer of smaller body size. The month in which younger juveniles' intake dropped below that of other age classes highlights the quickly changing risks, especially for those just transitioning from maternal dependence. I surprisingly found no response of individual growth velocity to nutritional intake among juveniles. However, maternal investment earlier in life did affect size-for-age. Likewise, faster growth rates in females may have fitness benefits if younger dispersal ages are an indication of earlier reproductive maturity. Thus, understanding factors that influence variation in growth rates and size-for-age offers insight into early selective pressures, which likely have long-term consequences for reproductive success."},{"label":"dcterms.available","value":"2017-09-20T16:51:34Z"},{"label":"dcterms.contributor","value":"Borries, Carola"},{"label":"dcterms.creator","value":"Ossi-Lupo, Kerry Michele"},{"label":"dcterms.dateAccepted","value":"2017-09-20T16:51:34Z"},{"label":"dcterms.dateSubmitted","value":"2017-09-20T16:51:34Z"},{"label":"dcterms.description","value":"Department of Anthropology."},{"label":"dcterms.extent","value":"253 pg."},{"label":"dcterms.format","value":"Monograph"},{"label":"dcterms.identifier","value":"http://hdl.handle.net/11401/76977"},{"label":"dcterms.issued","value":"2015-08-01"},{"label":"dcterms.language","value":"en_US"},{"label":"dcterms.provenance","value":"Made available in DSpace on 2017-09-20T16:51:34Z (GMT). No. of bitstreams: 1\nOssiLupo_grad.sunysb_0771E_12231.pdf: 2227512 bytes, checksum: 8ee8546fa63a4e029d63b7e28653d1ae (MD5)\n  Previous issue date: 2014"},{"label":"dcterms.publisher","value":"The Graduate School, Stony Brook University: Stony Brook, NY."},{"label":"dcterms.subject","value":"Physical anthropology"},{"label":"dcterms.title","value":"Nutritional Ecology and Growth in Juvenile Phayre's Leaf Monkeys"},{"label":"dcterms.type","value":"Dissertation"},{"label":"dc.type","value":"Dissertation"}],"description":"This manifest was generated dynamically","viewingDirection":"left-to-right","sequences":[{"@type":"sc:Sequence","canvases":[{"@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/canvas/page-1.json","@type":"sc:Canvas","label":"Page 1","height":1650,"width":1275,"images":[{"@type":"oa:Annotation","motivation":"sc:painting","resource":{"@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/14%2F54%2F34%2F145434559033405046998164493997291960404/full/full/0/default.jpg","@type":"dctypes:Image","format":"image/jpeg","height":1650,"width":1275,"service":{"@context":"http://iiif.io/api/image/2/context.json","@id":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/14%2F54%2F34%2F145434559033405046998164493997291960404","profile":"http://iiif.io/api/image/2/level2.json"}},"on":"https://repo.library.stonybrook.edu/cantaloupe/iiif/2/canvas/page-1.json"}]}]}]}