02554nas a2200193 4500008004100000245007500041210006900116520185900185653001702044653004502061653001202106653002902118653001102147653001302158100001702171700002602188700002602214856012002240 2011 eng d00aNo evidence for DPOAEs in the mechanical motion of the locust tympanum0 aNo evidence for DPOAEs in the mechanical motion of the locust ty3 a

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.

10abioacoustics10adistortion-product otoacoustic emissions10ahearing10alaser Doppler vibrometry10alocust10atympanum1 aMoir, H., M.1 aJackson, Joseph, Curt1 aWindmill, James, F.C. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.056465https://syndication.highwire.org/content/doi/10.1242/jeb.05646502286nas a2200121 4500008004100000245007100041210006700112520188600179100002002065700001502085700002302100856004102123 1989 eng d00aThe neuroethology of acoustic startle and escape in flying insects0 aneuroethology of acoustic startle and escape in flying insects3 a

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.

1 aHoy, Ronald, R.1 aNolen, Tom1 aBrodfuehrer, Peter uhttps://bio.acousti.ca/fi/node/5766801713nas a2200145 4500008004100000022001400041245011100055210006900166260001600235300000800251490000700259520123500266100001701501856004901518 1972 eng d a0004-959X00aCommunicative aspects of reproductive behaviour in Australian grasshoppers (Oedipodinae and Gomphocerinae)0 aCommunicative aspects of reproductive behaviour in Australian gr cJan-01-1972 a1390 v203 a

Communicative behaviour of nine species of Australian grasshoppers (seven Oedipodinae and two Gomphocerinae) is described and compared to North American and European species. Most signal types are represented in all three continents. Most similarities between the three groups are probably due to the retention of characteristics present in common ancestors. Other similarities evidently are convergent (i.e. arose independently in each continent); these include: (1) loss of femoro-tegminal stridulation in several species; (2) changes in the function of signals from one communicative context to another; (3) the ritualization of kicking movements (i.e. the evolution of signals from non-communicative kicking movements) ; (4) the evolution of specialized flight sounds in the Gomphocerinae. Female attracting flight displays are performed by relatively few Australian Oedipodinae. Characteristics of an individual that are closely associated with behaviour or physiological states of that individual and that are relevant to the activities or wellbeing of other individuals have a greater probability of becoming signals (becoming ritualized) than movements that occur in many situations (i.e. that are unpredictable).

1 aOtte, Daniel uhttp://www.publish.csiro.au/?paper=ZO972013900594nas a2200157 4500008004100000022001400041245014500055210006900200260001600269300001400285490000700299100002100306700001900327700001800346856007200364 1969 eng d a0031-935X00aThe Stridulation of Sexually Mature Males of Locusta migratoria migratorioides (R. and F.) in Relation to Temperature and Some Other Factors0 aStridulation of Sexually Mature Males of Locusta migratoria migr cJan-10-1969 a417 - 4280 v421 aBar-Ilan, A., R.1 aShulov, A., S.1 aPener, M., P. uhttp://www.journals.uchicago.edu/doi/10.1086/physzool.42.4.3015551300410nas a2200133 4500008004100000022001400041245005900055210005900114260001600173300001400189490000800203100001700211856004800228 1983 eng d a0340-759400aHind femora influence directionality of the locust ear0 aHind femora influence directionality of the locust ear cJan-01-1983 a509 - 5160 v1521 aAdam, L., J. uhttp://link.springer.com/10.1007/BF00606440