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Displacement experiments with amblypygids, nocturnal arachnids that inhabit the tropics and subtropics, revealed that they are rather extraordinary navigators and that their abilities are severely impeded when access to olfactory information is experimentally abolished. These results and the fact that amblypygids possess exceptionally large mushroom bodies, brain regions that process olfactory and, perhaps, spatial information led to the hypothesis that olfaction facilitates their navigation behavior. The amblypygid Phrynus marginemaculatus wanders nightly and shows strong shelter fidelity in a laboratory arena. Here, individual subjects were trained over a 26-night session in a square arena that contained two shelters to determine the extent to which shelter recognition is dictated by odor. The target shelter was positioned at a specific location in the arena near an acrylic well that contained 15 µl of geraniol. The other shelter was likewise positioned at a particular location in the arena, but near an acrylic well that contained 15 µl of water. The session consisted of nights on which the entrance to the target shelter was open and the entrance to the other shelter was closed, referred to as forced choice trials, and nights on which a subject had access to both shelters, referred to as probe trials. Probe trials involved manipulations of the locations of the shelters and their associated acrylic wells after a subject emerged from the target shelter. The probes consisted of three types of manipulations: control manipulations in which the shelters and associated acrylic wells were removed and replaced with identical shelters and dishes in their original locations; manipulations in which the positions of the two acrylic wells were swapped; and manipulations in which both shelters and their respective acrylic wells were moved from their original, trained locations. The odor-cued shelter was chosen in more than 90 percent of the control probes, but in the other two probe conditions shelters appear to have been chosen randomly. Thus, shelter choice was not dictated by odor. In addition, subjects did not rely primarily on path integration, a commonly applied navigation strategy in arthropods, as they did not chose the shelter in the original location of the odor-cued shelter in probes where only the positions of the acrylic wells were swapped. Instead, the results suggest that amblypygids, like ants, may use a configuration of cues to relocate and identify a shelter.

Proper neuronal function requires the preservation of appropriate neural excitability. An adaptive increase in neural excitability after exposure to agents that depress neuronal signaling blunts the sedative drug effects upon subsequent drug exposure. This adaptive response to drug exposure leads to changes in drug induced behaviors such as tolerance, withdrawal and addiction. Here I use Drosophila melanogaster to study the cellular and neuronal components which mediate behavioral tolerance to the anesthetic benzyl alcohol. I demonstrate that rapid tolerance to benzyl alcohol is a pharmacodynamic mechanism independent of drug metabolism. Furthermore, tolerance is a cell autonomous response which occurs in the absence of neural signaling. Using genetic and pharmacological manipulations I find the synapse to play an important role in the development of tolerance. In addition, the neural circuits that regulate arousal and sleep also alter benzyl alcohol sensitivity. Beyond previously described transcriptional mechanisms I find a post-translational role of the Ca2+-activated K+-channel, slowpoke in the development of tolerance. Finally, I explore a form of juvenile onset tolerance, which may have origins that differ from rapid tolerance. The implications of this study go beyond tolerance in Drosophila melanogaster to benzyl alcohol and can shed light on human drug tolerance, withdrawal and addiction.