1Department of Anthropology, Washington University in St. Louis, 2Department of Applied Biological Chemistry, University of Tokyo, 3Department of Integrated Biosciences, University of Tokyo, 4Department of Anthropology, University of Calgary, 5Department of Biological Sciences, Dartmouth College, 6Department of Anthropology, Hunter College, City University of New York
March 26, 2015 8:45, Grand Ballroom E/F/G
Senses serve as the interface between animals and the external environment and are critical during food detection and evaluation. Most primates consume ripe fruits and are typically viewed as “visual” animals. The non-visual senses, such as smell (olfaction) and touch (somatosensation), have been undervalued in the study of primate sensory ecology. Yet primates routinely sniff and squeeze fruit during assessment before consumption. We integrate foraging data from a 12-month behavioral study of white-faced capuchins (Cebus capucinus) with olfactory (volatile organic compounds –VOCs), haptic (force resistance) and visual (spectral reflectance) signals of fruit ripeness that are available to primates, along with fruit nutrition composition at different ripeness stages. We find: 1) distinct odor profiles (number, diversity and total VOCs) in fruits at different stages of mechanical ripeness; 2) that haptic (mechanical) and olfactory (VOC) changes in fruits are significantly related to nutritional ripening (n=7, p=0.0042); and 3) that olfactory and mechanical cues are a better indicator of ripeness than visual (color and size) changes are for some fruit species. Specifically, color changes can occur prior to fruit softening, final odorant shifts, and before the fruit is nutritionally ripe. These results support a role for color in long-distance signaling to attract foraging animals, which must then use different close-range evaluation methods (touching and sniffing) to assess the edibility of individual fruits. This study contributes to our knowledge about the foraging cues available to primates and other frugivores, and how multiple sensory modalities can inform food assessment and selection.
We thank NSERC, Sigma Xi, The Leakey Foundation, The Wenner-Gren Foundation, the Animal Behavior Society, the Japanese Society for the Promotion of Science, Alberta Innovates, the International Primatological Society.