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- Genre: Doctoral Dissertation
Description
Food is an essential driver of animal behavior. For social organisms, the acquisition of food guides interactions with the environment and with group-mates. Studies have focused on how social individuals find and choose food sources, and share both food and information with group-mates. However, it is often not clear how experiences throughout an individual's life influence such interactions. The core question of this thesis is how individuals’ experience contributes to within-caste behavioral variation in a social group. I investigate the effects of individual history, including physical injury and food-related experience, on individuals' social food sharing behavior, responses to food-related stimuli, and the associated neural biogenic amine signaling pathways. I use the eusocial honey bee (Apis mellifera) system, one in which individuals exhibit a high degree of plasticity in responses to environmental stimuli and there is a richness of communicatory pathways for food-related information. Foraging exposes honey bees to aversive experiences such as predation, con-specific competition, and environmental toxins. I show that foraging experience changes individuals' response thresholds to sucrose, a main component of adults’ diets, depending on whether foraging conditions are benign or aversive. Bodily injury is demonstrated to reduce individuals' appetitive responses to new, potentially food-predictive odors. Aversive conditions also impact an individual's social food sharing behavior; mouth-to-mouse trophallaxis with particular groupmates is modulated by aversive foraging conditions both for foragers who directly experienced these conditions and non-foragers who were influenced via social contact with foragers. Although the mechanisms underlying these behavioral changes have yet to be resolved, my results implicate biogenic amine signaling pathways as a potential component. Serotonin and octopamine concentrations are shown to undergo long-term change due to distinct foraging experiences. My work serves to highlight the malleability of a social individual's food-related behavior, suggesting that environmental conditions shape how individuals respond to food and share information with group-mates. This thesis contributes to a deeper understanding of inter-individual variation in animal behavior.
ContributorsFinkelstein, Abigail (Author) / Amdam, Gro V (Thesis advisor) / Conrad, Cheryl (Committee member) / Smith, Brian (Committee member) / Neisewander, Janet (Committee member) / Bimonte-Nelson, Heather A. (Committee member) / Arizona State University (Publisher)
Created2017
Description
Social animals benefit from the aggregation of knowledge and cognitive processing power. Part of this benefit comes from individual heterogeneity, which provides the basis to group-level strategies, such as division of labor and collective intelligence. In turn, the outcomes of collective choices, as well as the needs of the society at large, influence the behavior of individuals within it. My dissertation research addresses how the feedback between individual and group-level behavior affects individuals and promotes collective change. I study this question in the context of seed selection in the seed harvester ant, Pogonomyrmex californicus. I use both field and laboratory studies to explore questions relating to individual behavior: how forager decision-making is affected through information available in the nest and at the seed pile; how workers interact with seeds in the nest; and how forager preferences diverge from each other’s and the colony’s preference. I also explore the integration between individual and colony behavior, specifically: how interactions between the foraging and processing tasks affect colony collection behavior; how individual behavior changes affect colony preference changes and whether colony preference changes can be considered learning behavior. To answer these questions, I provided colonies with binary choices between seeds of unequal or similar quality, and measured individual, task group, and colony-level behavior. I found that colonies are capable of learning to discriminate between seeds, and learned information lasts at least one month without seed interaction outside of the nest. I also found that colony learning was coordinated by foragers receiving updated information from seeds in the nest to better discriminate and make choices between seed quality during searches for seeds outside of the nest. My results show that seed processing is essential for stimulating collection of novel seeds, and that foraging and processing are conducted by behaviorally and spatially overlapping but distinct groups of workers. Finally, I found that foragers’ preferences are diverse yet flexible, even when colonies are consistent in their preference at the population level. These combined experiments generate a more detailed and complete understanding of the mechanisms behind the flexibility of collective colony choices, how colonies incorporate new information, and how workers individually and collectively make foraging decisions for the colony in a decentralized manner.
ContributorsBespalova, Ioulia Ivanovna (Author) / Fewell, Jennifer (Thesis advisor) / Hölldobler, Bert (Committee member) / Liebig, Jürgen (Committee member) / Pinter-Wollman, Noa (Committee member) / Pratt, Stephen (Committee member) / Arizona State University (Publisher)
Created2020
Description
Understanding the evolution of cooperation is a central goal in animal behavior research. In several animal taxa, socioecological environments that promote frequent interaction and social tolerance have favored the evolution of strong, equitable, and enduring social bonds, which facilitate cooperation and confer fitness benefits. Among males, strong bonds are believed to have evolved in the context of long-term alliances that help individuals compete for dominance status and mating access, but it remains unclear in some species what factors predict the strength and quality of bonds and how sociality relates to adaptive outcomes. To fill these gaps, this dissertation presents three studies of male chimpanzees at Gombe National Park, Tanzania, addressing the form, function, and development of male social relationships. Maternal brothers who were close in age formed the strongest bonds, strong bonds were associated with more reciprocal grooming relationships, and the strength of bonds were stable for an average of two years, while lasting up to 13 years. For other males, similarity in age and rank had negligible effects on bond strength, suggesting that bond strength results from a more complex process than a simple accounting of basic characteristics. Additionally, these social bonds, identified using both association in small groups and grooming activity, showed positive relationships with changes in dominance. In combination with prior studies, these results suggest that having strong bonds is a valuable strategy for achieving higher rank and, ultimately, increased reproductive success. Lastly, immature males who associated more with particular adult males while growing up were more likely to both associate and groom with those same males after entering adulthood. By contrast, association rates among immature male peers were not correlated with bond strength as adults. These findings suggest that the persistence of social relationships beyond those between mothers and offspring are more likely to evolve in long-lived species where young males enter adult hierarchies comprised of stronger or more socially experienced competitors. Overall, these studies reinforce the notion that social bonds are a chimpanzee universal, fill in gaps about the relationship between sociality and fitness, and emphasize the utility of a prolonged immature period.
ContributorsBray, Joel (Author) / Gilby, Ian C (Thesis advisor) / Silk, Joan B (Committee member) / Langergraber, Kevin E (Committee member) / Machanda, Zarin P (Committee member) / Arizona State University (Publisher)
Created2021