02286nas 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/fr/node/5766800342nam a2200097 4500008004100000245005500041210005400096260003100150100002200181856004100203 1989 eng d00aArthropod Bioacoustics: Neurobiology and Behaviour0 aArthropod Bioacoustics Neurobiology and Behaviour aIthaca, New YorkbComstock1 aEwing, Arthur, W. uhttps://bio.acousti.ca/fr/node/5759002551nas a2200157 4500008004100000022001400041245010500055210006900160260001600229300001400245490000800259520199200267100002102259700002802280856008502308 1989 eng d a0005-795900aSatellites and Transients: Ecological Constraints On Alternative Mating Tactics in Male Grasshoppers0 aSatellites and Transients Ecological Constraints On Alternative  cJan-01-1989 a200 - 2200 v1093 a

Alternative tactics of male mating behaviour, broadly classifiable as "dominant/ territorial" versus "subordinate/non-territorial", have now been described for numerous species. Furthermore, across diverse taxa the mating tactics of subordinate/non-territorial males often appear as one of two distinct types, satellite or transient behaviour. Despite general recognition of this dichotomy, though, little effort has been made to identify the circumstances under which one of these behaviours is adopted over the other. We compared the mating systems of two congeneric species of desert grasshoppers (genus Ligurotettix) to investigate specifically the role of resource dispersion in shaping the behaviour of subordinate males. The utility of the comparative approach derives from two basic similarities between the species: both Ligurotettix coquilletti and Ligurotettix planum feed almost exclusively on a single host plant species, and the majority of males in both species defend individual host plants to gain access to females. However, the two species are associated with host plants that are dispersed very differently; i.e., L. coquilletti encounter a small number of large plants and L. planum a large number of small ones. In L. coquilletti, subordinate males, individuals noted by their lack of success in aggression and in obtaining matings, were characterized as satellites that remained silent on host plants defended by territorial males. Subordinate males in L. planum, however, were transients that sang regularly but moved frequently among different host plants. We propose that this behavioural discrepancy results from (1) the large difference between the number of potential female encounter sites (i.e., individual host plants) available to the males of the two species and (2) the large difference between the sizes of resource patches defended by the two species, which influences the ability of dominant males to eject subordinates.

1 aShelly, Todd, E.1 aGreenfield, Michael, D. uhttp://booksandjournals.brillonline.com/content/journals/10.1163/156853989x0023102882nas a2200169 4500008004100000022001400041245011900055210006900174260001600243300001400259490000800273520231600281100002302597700002202620700002202642856004802664 1989 eng d a0340-759400aAuditory processing in the black-sided meadow katydid Conocephalus nigropleurum (Orthoptera: Tettigoniidae)0 aAuditory processing in the blacksided meadow katydid iConocephal cJan-01-1989 a501 - 5120 v1643 a

1. The auditory system of the tettigoniid,Conocephalus nigropleurum was examined using whole auditory nerve responses (averaged summed action potentials (SAPs)) and intracellularly recorded single cells (receptor and interneurone) to pure tone stimuli and con- and heterospecific (C. brevipennis) songs.

2.The morphology of the auditory tracheal system and crista acustica is documented forC. nigropleurum. A broadly open thoracic spiracle (stigma) leads, via a horn, camera and foreleg trachea to a crista acustica of 28 receptor cells.

3. C. nigropleurum's auditory sensitivity is broadly tuned to 15–35 kHz which is below the peak frequency band of its calling song (30–36 kHz). The ear possesses a dynamic range of at least 30 dB and pulsed sounds with short (<0.5 ms) onset times or long interpulse periods (>200 ms) elicit maximal responses. We suggest this is caused by increased auditory receptor firing synchrony to these types of sounds and may facilitate the location of such sounds. There is, however, discrepancy between the pulse periods that elicit maximal SAP amplitudes and those found within the normal calling song, a phenomenon which may be related to the chorusing behaviour of this species.

4.Polar directional plots indicate thatC. nigropleurum is most sensitive to sounds originating posterior to the opening of the prothoracic auditory stigma; this may be caused by the configuration of the prothoracic pronotum. We found no pronounced sensitivity at points facing the tympanal slits.

5.Intracellular recordings reveal prothoracic receptors with widely decussate and narrowly branched termini. No receptor tested was able to track the intra-phonatome pulses (tooth strike sounds) of either species and we conclude that the phonatome is the finest resoluble component of the song.

6. An acoustically-activated interneurone (101) was recorded that resembles both the gryllid int-2 (Omega) cell and that of another tettigoniid. We suggest that tonic interneuronal firing caused by the multiple singer chorused song of either species activates the initial stages of phonotaxis in receptiveC. nigropleurum females but individual species recognition may depend at least partially on the discrimination of phonatome rates.

1 aFullard, James, H.1 aMorris, Glenn, K.1 aMason, Andrew, C. uhttp://link.springer.com/10.1007/BF0061044400584nas a2200169 4500008004100000022001400041245012900055210006900184260001600253300001400269490000800283100001900291700001900310700001700329700002000346856004800366 1989 eng d a0340-759400aInfluence of syllable period on song encoding properties of an ascending auditory interneuron in the cricketAcheta domestica0 aInfluence of syllable period on song encoding properties of an a cJan-01-1989 a827 - 8360 v1651 aAtkins, Steven1 aAtkins, Gordon1 aRhodes, Mike1 aStout, John, F. uhttp://link.springer.com/10.1007/BF00610881