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- All Subjects: Primates--Evolution.
- Creators: Reed, Kaye E
Description
The earliest Eocene marked the appearance of the first North American euprimates (adapids, omomyids). Despite the fact that leading hypotheses assert that traits involved in food acquisition underlie euprimate origination and early diversification, the precise role that dietary competition played in establishing euprimates as successful members of mammalian communities is unclear. This is because the degree of niche overlap between euprimates and all likely mammalian dietary competitors ("the euprimate competitive guild") is unknown. This research determined which of three major competition hypotheses - non-competition, strong competition, and weak competition - characterized the late Paleocene-early Eocene euprimate competitive guild. Each of these hypotheses is defined by a unique temporal pattern of niche overlap between euprimates and their non-euprimate competitors, allowing an evaluation of the nature of dietary competitive interactions surrounding the earliest euprimates in North America. Dietary niches were reconstructed for taxa within the fossil euprimate competitive guild using molar morphological measures determined to discriminate dietary regimes in two extant mammalian guilds. The degree of dietary niche separation among taxa was then evaluated across a series of fossil samples from the Bighorn Basin, Wyoming just prior to, during, and after euprimate origination. Statistical overlap between each pair of euprimate and non-euprimate dietary niches was determined using modified multivariate pairwise comparisons using distances in a multidimensional principal component "niche" space. Results indicate that euprimate origination and diversification in North America was generally characterized by the absence of dietary competition. This lack of competition with non-euprimates is consistent with an increase in the abundance and diversity of euprimates during the early Eocene, signifying that the "success" of euprimates may not be the result of direct biotic interactions between euprimates and other mammals. An examination of the euprimate dietary niche itself determined that adapids and omomyids occupied distinct niches and did not engage in dietary competition during the early Eocene. Furthermore, changes in euprimate dietary niche size over time parallel major climatic shifts. Reconstructing how both biotic and abiotic mechanisms affected Eocene euprimates has the potential to enhance our understanding of these influences on modern primate communities.
ContributorsStroik, Laura (Author) / Schwart, Gary T (Thesis advisor) / Reed, Kaye E (Committee member) / Campisano, Christopher J (Committee member) / Gunnell, Gregg F. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Fundamental hypotheses about the life history, complex cognition and social dynamics of humans are rooted in feeding ecology - particularly in the experiences of young animals as they grow. However, the few existing primate developmental data are limited to only a handful of species of monkeys and apes. Without comparative data from more basal primates, such as lemurs, we are limited in the scope of our understanding of how feeding has shaped the evolution of these extraordinary aspects of primate biology. I present a developmental view of feeding ecology in the ring-tailed lemur (Lemur catta) using a mixed longitudinal sample (infant through adult) collected at the Beza Mahafaly Special Reserve in southwestern Madagascar from May 2009 to March 2010. I document the development of feeding, including weaning, the transition to solid food, and how foods are included in infant diets. Early in juvenility ring-tailed lemurs efficiently process most foods, but that hard ripe fruits and insects require more time to master. Infants and juveniles do not use many of the social learning behaviors that are common in monkeys and apes, and instead likely rely both on their own trial and error and simple local enhancement to learn appropriate foods. Juvenile ring-tailed lemurs are competent and efficient foragers, and that mitigating ecological risks may not best predict the lemur juvenile period, and that increases in social complexity and brain size may be at the root of primate juvenility. Finally, from juvenility through adulthood, females have more diverse diets than males. The early emergence of sex differences in dietary diversity in juvenility that are maintained throughout adulthood indicate that, in addition to reproductive costs incurred by females, niche partitioning is an important aspect of sex differential feeding ecology, and that ontogenetic studies of feeding are particularly valuable to understanding how selection shapes adult, species-typical diets. Overall, lemur juvenility is a time to play, build social relationships, learn about food, and where the kernels of sex-typical feeding develop. This study of the ontogeny of feeding ecology contributes an important phylogenetic perspective on the relationship between juvenility and the emergent foraging behaviors of developing animals
ContributorsO'Mara, Michael Teague (Author) / Nash, Leanne T. (Thesis advisor) / Reed, Kaye E (Committee member) / Schwartz, Gary T (Committee member) / Sauther, Michelle L (Committee member) / Arizona State University (Publisher)
Created2012