The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

Do diet and evolutionary history predict variation in life history variables better than environmenal harshness for lemur traits?


1Anthropology, University of Miami, 2Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University

March 26, 2015 , Archview Ballroom Add to calendar

Lemurs exhibit a suite of traits unique among primates, including rapid infant development, fibrous diet, and diverse activity patterns. These traits are hypothesized to be adaptive to harsh Malagasy environments, resource extraction, and/or represent recent evolutionary transitional states. We compiled data on morphology, life history (LH), environment and diet for 100+ taxa to test these hypotheses: 1) LH traits are predicted by environment, diet, and/or activity pattern, and 2) lemurs differ from other primates in LH traits (Phylogenetic ANCOVA). We tested for uniqueness of adaptive regimes by dietary niche. Lemurs differ significantly from other primates in shorter weaning times, gestations, and inter-birth intervals (IBI), as well as larger litter size (likelihood ratio test, LRT, vs null hypothesis = 9.63, p=0.047). Diet predicts LH, with shorter IBI and weaning times in folivores than frugivores or omnivores (LRT vs null = 7.10, p=0.03). An adaptive peak with high selective constraint (alpha parameter ~0.15) best fits the model. Annual precipitation (harshness variable) does not explain variation in LH. Life history likely evolved towards unique optima with different levels of selective constraint among dietary regimes: folivores have fastest life histories/ weakest selective constraints whereas frugivores and omnivores have slower life histories/ stronger selective constraints. Lemurs have faster LH than other primates, with diet, not environmental harshness, being the salient predictor of their LH dynamics. The folivore fast-lane is an adaptive optimum, suggesting resource extraction, rather than adaptation to a harsh environment or evolutionary disequilibrium, as the primary driver of lemur life history.

This work was supported in part by the Turner Fellowship and AGEP-T FRAME Scholarship (SBU), the NSF GRFP (JPH), and a UM Provost’s Innovative Teaching and Research award (LLT).