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- All Subjects: honey bee
- Creators: Cook, Chelsea
Description
The ability to detect and appropriately respond to chemical stimuli is important for many organisms, ranging from bacteria to multicellular animals. Responses to these stimuli can be plastic over multiple time scales. In the short-term, the synaptic strengths of neurons embedded in neural circuits can be modified and result in various forms of learning. In the long-term, the overall developmental trajectory of the olfactory network can be altered and synaptic strengths can be modified on a broad scale as a direct result of long-term (chronic) stimulus experience. Over evolutionary time the olfactory system can impose selection pressures that affect the odorants used in communication networks. On short time scales, I measured the effects of repeated alarm pheromone exposure on the colony-level defense behaviors in a social bee. I found that the responses to the alarm pheromone were plastic. This suggests that there may be mechanisms that affect individual plasticity to pheromones and regulate how these individuals act in groups to coordinate nest defense. On longer time scales, I measured the behavioral and neural affects of bees given a single chronic odor experience versus bees that had a natural, more diverse olfactory experience. The central brains of bees with a deprived odor experience responded more similarly to odorants in imaging studies, and did not develop a fully mature olfactory network. Additionally, these immature networks showed behavioral deficits when recalling odor mixture components. Over evolutionary time, signals need to engage the attention of and be easily recognized by bees. I measured responses of bees to a floral mixture and its constituent monomolecular components. I found that natural floral mixtures engage the orientation of bees’ antennae more strongly than single-component odorants and also provide more consistent central brain responses between stimulations. Together, these studies highlight the importance of olfactory experience on different scales and how the nervous system might impose pressures to select the stimuli used as signals in communication networks.
ContributorsJernigan, Christopher (Author) / Smith, Brian H. (Thesis advisor) / Newbern, Jason (Committee member) / Harrisoin, Jon (Committee member) / Rutowski, Ronald (Committee member) / Pratt, Stephen (Committee member) / Arizona State University (Publisher)
Created2018
Description
Division of labor is a hallmark for social insects and is closely related to honey bee morphology and physiology. Vitellogenin (Vg), a precursor protein in insect egg yolk, has several known functions apart from serving as a nutrient source for developing eggs. Vg is a component in the royal jelly produced in the hypopharyngeal glands (HPG) of worker bees which is used to feed both the developing brood and the queen. The HPG is closely associated with divisions of labor as the peak in its development corresponds with the nursing behavior. Independent of the connection between Vg and the HPG, Vg has been seen to play a fundamental role in divisions of labor by affecting worker gustatory responses, age of onset of foraging, and foraging preferences. Similar to Vg, the number of ovarioles in worker ovaries is also associated with division of labor as bees with more ovarioles tend to finish tasks in the hive and become foragers faster. This experiment aims to connect HPGs, ovaries, and Vg by proposing a link between them in the form of ecdysone (20E). 20E is a hormone produced by the ovaries and is linked to ovary development and Vg by tyramine titers. By treating young emerged bees with ecdysone and measuring HPG and ovary development over a trial period, this experiment seeks to determine whether 20E affects division of labor through Vg. We found that though the stress of injection caused a significant decrease in development of both the ovaries and HPG, there was no discernable effect of 20E on either of these organs.
ContributorsChin, Elijah Seth (Author) / Wang, Ying (Thesis director) / Page, Robert (Committee member) / Cook, Chelsea (Committee member) / School of Molecular Sciences (Contributor) / W. P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Honeybees require the use of their antennae to perceive different scents and pheromones, communicate with other members of the colony, and even detect wind vibrations, sound waves, and carbon dioxide levels. Limiting and/or removing this sense makes bees much less effective at acquiring information. However, how antennal movements might be important for olfaction has not been studied in detail. The focus of this work was to evaluate how restriction of antennae movements might affect a bee’s ability to detect and perceive odors. Bees were made to learn a certain odor and were then split up into a control group, a treatment group that had their antennae fixed with eicosane, and a sham treatment group that had a dot of eicosane on their heads in such a way that it would not affect antennae movements but still add the same amount of weight. Following a period of acclimation, the bees were tested with the conditioned odor, one that was perceptually similar to it, and to a dissimilar odor. Using proboscis-extension duration and latency as response measures, it became clear that both antenna fixation and sham treatments affected the conditioned behavior. However, these treatment effects did not reach statistical significance. Briefly, both fixation of antennae as well as the sham treatment reduced the discriminability of the conditioned and similar odors. Although more data can be collected to more fully evaluate the significance of the treatments, the behavior of the sham group could indicate that mechanoreceptive hairs on the head play an important role in olfaction. It is also possible that there are other factors at play, possibly induced by the fixed bees’ increased stress levels.
ContributorsHozan, Alvin Robert (Author) / Smith, Brian H (Thesis advisor) / Lei, Hong (Committee member) / Cook, Chelsea (Committee member) / Arizona State University (Publisher)
Created2021