@article {57946, title = {No evidence for DPOAEs in the mechanical motion of the locust tympanum}, year = {2011}, abstract = {

Distortion-product otoacoustic emissions (DPOAEs) are present in non-linear hearing organs, and for low-intensity sounds are a by-product of active processes. In vertebrate ears they are considered to be due to hair cell amplification of sound in the cochlea; however, certain animals lacking a cochlea and hair cells are also reported to be capable of DPOAEs. In the Insecta, DPOAEs have been recorded from the locust auditory organ. However, the site of generation of these DPOAEs and the physiological mechanisms causing their presence in the locust ear are not yet understood, despite there being a number of potential places in the tympanal organ that could be capable of generating DPOAEs. This study aimed to record locust tympanal membrane vibration using a laser Doppler vibrometer in order to identify a distinct place of DPOAE generation on the membrane. Two species of locust were investigated over a range of frequencies and levels of acoustic stimulus, mirroring earlier acoustic recording studies; however, the current experiments were carried out in an open acoustic system. The laser measurements did not find any evidence of mechanical motion on the tympanal membrane related to the expected DPOAE frequencies. The results of the current study therefore could not confirm the presence of DPOAEs in the locust ear through the mechanics of the tympanal membrane. Experiments were also carried out to test how membrane behaviour altered when the animals were in a state of hypoxia, as this was previously found to decrease DPOAE magnitude, suggesting a metabolic sensitivity. However, hypoxia did not have any significant effect on the membrane mechanics. The location of the mechanical generation of DPOAEs in the locust\’s ear, and
therefore the basis for the related physiological mechanisms, thus remains unknown.

}, keywords = {bioacoustics, distortion-product otoacoustic emissions, hearing, laser Doppler vibrometry, locust, tympanum}, doi = {10.1242/jeb.056465}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.056465https://syndication.highwire.org/content/doi/10.1242/jeb.056465}, author = {Moir, H. M. and Joseph Curt Jackson and James F.C. Windmill} } @article {57668, title = {The neuroethology of acoustic startle and escape in flying insects}, year = {1989}, abstract = {

The acoustic startle/escape response is a phylogenetically widespread behavioral act, provoked by an intense, unexpected sound. At least six orders of insects have evolved tympanate ears that serve acoustic behavior that ranges from sexual communication to predator detection. Insects that fly at night are vulnerable to predation by insectivorous bats that detect and locate their prey by using biosonar signals. Of the six orders of insects that possess tympanate hearing organs, four contain species that fly at night and, in these, hearing is sensitive to a range of ultrasonic frequencies found in the biosonar signals of bats. Laboratory and field studies have shown that these insects (including some orthopterans, lepidopterans, neuropterans and dictyopterans), when engaged in flight behavior, respond to ultrasound by suddenly altering their flight, showing acoustic startle or negative phonotaxis, which serve as bat-avoidance behavior. A neural analysis of ultrasound-mediated escape behavior was undertaken in the field cricket Telegryllus oceanicus. An identified thoracic interneuron, int-1, was shown to trigger the escape response, but only when the cell was driven (synaptically or electrically) at high spike rates, and only when the insect was performing flight behavior; avoidance steering only occurs in the appropriate behavioral context: flight. Thus, significant constraints operate upon the ability of int-1 to trigger the escape response. The integration of auditory input and flight central pattern generator output occurs in the brain. It is found that neural activity descending from the brain in response to stimulation by ultrasound is increased when the insect is flying compared to when it is not. Although the behavioral act of avoidance steering may appear to be a simple reflex act, further analysis shows it to be anything but simple.

}, author = {Ronald R. Hoy and Nolen, Tom and Brodfuehrer, Peter} } @article {17251, title = {The Stridulation of Sexually Mature Males of Locusta migratoria migratorioides (R. and F.) in Relation to Temperature and Some Other Factors}, journal = {Physiological Zoology}, volume = {42}, year = {1969}, month = {Jan-10-1969}, pages = {417 - 428}, issn = {0031-935X}, doi = {10.1086/physzool.42.4.30155513}, url = {http://www.journals.uchicago.edu/doi/10.1086/physzool.42.4.30155513}, author = {Bar-Ilan, A. R. and A. S. Shulov and M. P. Pener} } @article {17172, title = {Hind femora influence directionality of the locust ear}, journal = {Journal of Comparative Physiology ? A}, volume = {152}, year = {1983}, month = {Jan-01-1983}, pages = {509 - 516}, issn = {0340-7594}, doi = {10.1007/BF00606440}, url = {http://link.springer.com/10.1007/BF00606440}, author = {Adam, L. J.} }