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Title:Focused orientation of campaniform sensilla on Periplaneta americana L. (Orthoptera: Blattidae) trochanters and femurs
Author(s):Steinly, Bruce Allen, Jr
Doctoral Committee Chair(s):Metcalf, Robert L.
Department / Program:Entomology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Neuroscience
Biology, Entomology
Abstract:Campaniform sensilla orientations on the trochanters and femora of Periplaneta americana are described. Vector construction that simulate mechanical strains impinging on individual campaniform sensilla and sensilla fields suggests that these structures are focused on strain origin points adjacent to or within the femur-trochanter and coxa-trochanter articulations. The variation in strain pathway lengths suggests that each field is responding to high and low intensity stimuli. A non-linear analysis confirms that CS 2, CS 3 and CS 4 campaniform sensilla orientations are concentrated while the orientation angles within CS 1 and CS 2 are randomly distributed.
Orientation overlap of campaniform sensilla fields suggests that depolarizations originating from each field are integrated. Intra- and inter-field functional integration is suggested by the frequency of parallel and series campaniform sensilla orientations. Although several campaniform sensilla are focused in series and/or parallel on a common stimulus origin, stimulus intensity, variation of the propagation pathway lengths, and cuticle conformation between the stimulus origin and campaniform sensilla may effect the temporal depolarization patterns. Within parallel and series focuses, low and high stimulus energies may yield different depolarization sequences, i.e., low energies depolarize near sensilla while high energies depolarize larger numbers of distant sensilla.
Within a theoretical model, the campaniform sensilla nearest the articulation surface(s) are depolarized first by weak deformational energies. Weak energies that exceed cuticular resistance and sensory cell thresholds and, ultimately, depolarize the attached neuron(s) will not be propagated great distances through a relatively inelastic cuticle and depolarize distant sensilla. The position of campaniform sensilla and angle of strain propagation within fields, and magnitude of strain energy limits the number of depolarization combinations. The probable number of depolarization sequences is reduced by propagation distance similarities to approximately 1/10 of the predicted. P. americana has retained more than 249,000 bilateral depolarization combination possibilities. Examination of pro-, and meso-, and metathoracic legs suggests that intra- and inter- field associations account for 33.0%, 35.4%, and 31.6% of the depolarization combinations, respectively. The presence of supernumerary campaniform sensilla and the distribution of sensilla fields are discussed within an evolutionary contexts.
Issue Date:1991
Rights Information:Copyright 1991 Steinly, Bruce Allen, Jr
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9136744
OCLC Identifier:(UMI)AAI9136744

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