02285nas a2200145 4500008004100000245010500041210006900146300001200215490000700227520178100234100002302015700002602038700002602064856004902090 1995 eng d00aChorus structure in tarbush grasshoppers: inhibition, selective phonoresponse and signal competition0 aChorus structure in tarbush grasshoppers inhibition selective ph a279-5940 v503 a

In species where sexually advertising males signal in groups, the timing of an individual's signals relative to those of neighbours may be a critical aspect of mating success. Temporal signal interactions and their relation to female attraction were examined in the tarbush grasshopper, Ligurotettix planum. The acoustic signals of neighbouring L. planum males form a crudely alternating chorus. Alternation within male pairs is effected by an (inhibitory resetting) mechanism that causes a male to refrain from calling for at least a 1·8-s interval beginning 0·2s after the onset of a neighbour's call. This mechanism is not equally applied to all neighbours. Rather, males are selectively inhibited by only their nearest one or two neighbours, whereas more distant, but audible, callers are ignored. Males also time their calls to occur shortly before calls at the ends of predictable recurring silent intervals. Consequently, males do not decrease their calling rates in high population density, and they compete effectively for females. Phonotaxis in L. planum females is characterized by preference for leading calls, a psychoacoustic feature that would select for timng mechanisms that avert the production of following calls in males. The inhibitory resetting mechanism averts such calls. Moreover, because males are only inhibited by nearest neighbours, their strongest competitors, they can avoid producing unattractive following calls and still maintain normal calling rates. By calling at the ends of silent intervals, males may actively compete with neighbours via ‘attempting’ to relegate the neighbours' calls to ineffective, from the neighbour's perspective, time intervals following the focal male's call.

1 aL.Minckley, Robert1 aD.Greenfield, Michael1 aK.Tourtellot, Michael uhttps://doi.org/10.1016/0003-3472(95)80121-902548nas a2200097 4500008004100000245018400041210006900225520198700294100002102281856014802302 1995 eng d00aThe biology of the phonotactic parasitoid, Homotrixa sp. (Diptera: Tachinidae), and its impact on the survival of male Sciarasaga quadrata (Orthoptera: Tettigoniidae) in the field0 abiology of the phonotactic parasitoid Homotrixa sp Diptera Tachi3 a

1. Unlike most parasitoids, tachinid flies of the tribe Ormiini use sound to locate their hosts. Although thought to exert selection pressure on their host's calling behaviour, little is known about the biology of ormiines. Accordingly, this study reports the biology and impact of the ormiine Hornotrixa sp. upon calling males of the univoltine bushcricket Sciarasaga quadrata Rentz in south‐western Australia.

2. Populations of adult S.quadrata were monitored in the field over two successive calling seasons. Females, which do not call, were not parasitized by Hornotrixa sp., but the risk of parasitism for males increased as the 3‐month calling season progressed. Parasitism did not commence until c. 2 weeks into the calling season, but by the end of the season up to 87% of surviving males were parasitized.

3. Parasitized males lived for 14 days and were found singing until their penultimate evening before death in the field. Unparasitized males lived on average 69 days and a maximum of 119 days.

4. Multiparasitism of hosts was common, with up to sixteen fly larvae found within parasitized males. The number of fly larvae within hosts significantly increased at the end of the season. However, successful emergence of fly larvae from hosts, as well as pupal size, significantly decreased as more than one fly larva developed within the host.

5. Homotrixa sp. has a long pupal duration of 30–31 days at 20°C. As a consequence, only one complete fly generation, which overwinters in the pupal stage, is likely within each host generation.

6. No evidence for differential (size‐bias) mortality by Homotrixa sp. on male S.quadrata was found. The size of parasitized and unparasitized males collected in the field was not significantly different.

7. It is concluded that Homotrixa sp. is a significant mortality factor acting on the survival of adult male S.quadrata.

1 aALLEN, GEOFF, R. uhttp://doi.wiley.com/10.1111/j.1365-2311.1995.tb00435.xhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2311.1995.tb00435.x01924nas a2200157 4500008004100000022001300041245014500054210006900199260001600268300001400284490000700298520136100305100001601666700001901682856006501701 1995 eng d a0022191000aEffects of a tachinid parasitoid, Ormia ochracea, on the behaviour and reproduction of its male and female field cricket hosts (Gryllus spp)0 aEffects of a tachinid parasitoid Ormia ochracea on the behaviour cJan-03-1995 a269 - 2770 v413 a

The larvae of the tachinid parasitoid fly, Ormia ochracea, develop within the body of their host, the field crickets Gryllus integer and Gryllus rubens. The fly will also develop within the cricket Gryllus bimaculatus, which is not the natural host. For the first 3 days after entering a cricket, the first instar larvae grew inside the large thoracic muscles, but did little damage to the muscles during this time. They then migrated into the abdomen where they moulted, attached themselves to the body wall and fed primarily on the host's muscle and fat body, sparing the digestive system and CNS. Usually the host's reproductive system was only partially damaged. After the larvae entered the abdominal cavity, the host's mating, egg-laying and fighting ability (males) declined. This decline probably occurred due to the tissue damage wrought by the parasitoid. Less energy-demanding behaviours, such as grooming and feeding, were not affected during the entire period of infestation. During the first instar (when the parasitoid is embedded in the host's muscle), male crickets showed an increased tendency to attack other males. This increased incidence of agonistic behaviour occurred before the parasitoid caused significant tissue damage to the host and must therefore have been due to some other effect of the parasitoid.

1 aAdamo, S.A.1 aRobert, Daniel uhttp://linkinghub.elsevier.com/retrieve/pii/002219109400095X00469nas a2200145 4500008004100000022001400041245007600055210006900131260001600200300001200216490000700228100002200235700001800257856004800275 1995 eng d a0028-104200aCovert stridulation: Novel sound generation by a South American Katydid0 aCovert stridulation Novel sound generation by a South American K cJan-02-1995 a96 - 980 v821 aMorris, Glenn, K.1 aMason, A., C. uhttp://link.springer.com/10.1007/BF0114015101524nas a2200157 4500008004100000022001400041245010700055210006900162260000900231300001000240490000800250520104000258100001501298700001201313856004101325 1995 eng d a1477-914500aBioacoustics of a miniature cricket, Cycloptiloides canariensis (Orthoptera: Gryllidae: Mogoplistinae)0 aBioacoustics of a miniature cricket Cycloptiloides canariensis O c1995 a721-80 v1983 a

Male crickets, Cycloptiloides canariensis (body length 5 mm), stridulate with their forewings, which are hidden during rest under the large shield-like pronotum. The wings are opened into the stridulatory position by bending the body between the pro- and mesothorax. The song is a 2 s trill composed on average of 260 pulses (syllables) with a carrier frequency of about 6 kHz. The sound-emitting structures on the wings have been studied by laser vibrometry and particle dusting. A distinct membrane area, which includes a prominent mirror cell, acts as a resonator, amplifying the fundamental carrier frequency produced by interactions between the file and plectrum. The resonating membrane is extremely thin (mirror cell thickness 0.2 µm), which is a physical requirement for maintaining the carrier frequency in the cricket-specific range. Covering the wings after singing is probably an adaptation to protect these delicate structures from damage by mechanical contact during social interactions, especially mating.

1 aDambach, M1 aGras, A uhttps://bio.acousti.ca/it/node/4788201872nas a2200157 4500008004100000022001300041245011900054210006900173260001600242300001600258490000700274520132800281100002001609700002001629856006501649 1995 eng d a0003347200aFitness differences associated with calling behaviour in the two wing morphs of male sand crickets, Gryllus firmus0 aFitness differences associated with calling behaviour in the two cJan-01-1995 a1475 - 14810 v503 a

Alternate morphologies exist in a wide range of species. A commonly encountered dimorphism in insects is wing dimorphism, in which one morph is winged (macropterous=LW) and flight-capable while the other has reduced wings (micropterous=SW) and cannot fly. Gryllus firmus is a wing-dimorphic cricket found in the southeastern U.S.A. Although trade-offs associated with wing dimorphism are well established in female crickets, no such trade-offs have been demonstrated in male crickets. Differences between morphs in male G. firmus in the likelihood of attracting a female were tested in the laboratory using a simple T-maze where females chose between an LW male and an SW male. Time spent caling for each male was recorded on the sixth day of adult life. SW males were more likely to attract a female and spent more time calling than LW males. A logistic regression of female choice against the absolute proportional difference in calling time between males revealed that, as the difference in calling time between males increased, the likelihood of a female choosing the longer-calling male also increased. Therefore it is concluded that there is a trade-off between macroptery and the likelihood of attracting a female, and that it may be a primary factor in the maintenance of wing dimorphism in male G. firmus.

1 aCrnokrak, Peter1 aRoff, Derek, A. uhttp://linkinghub.elsevier.com/retrieve/pii/000334729580004203485nas a2200133 4500008004100000022001300041245011700054210006900171260001600240300000700256520300800263100002403271856005603295 1995 eng d a1082646700aCosts of Calling in Tettigoniid Orthoptera: A Case Study of Requena verticalis (Tettigoniidae: Listroscelidinae)0 aCosts of Calling in Tettigoniid Orthoptera A Case Study of Reque cJan-08-1995 a653 a

The tettigoniid Requena verticalis Walker controls the apportioning of energy between calling and spermatophylax
production during courtship and copulation. Males delay the onset of calling following mating and during this period nutrients are
mobilized to the production of a large nutrient-rich spermatophylax as well as to the production of sound. Experiments, using males
reared on high and low quality diets (Simmons et al. 1993) examined the distribution of metabolic resources during this post-copula
refractory period. An experimental set of males was allowed to call in a period immediately following copulation, while a control group
of animals was prevented from calling by waxing the wings together. Males maintain spermatophylax size, regardless of the quality
of the diet, but delayed the onset of calling; those on a high quality diet were able to invest energy into further reproduction. Contrary
to prediction, males prevented from calling did not produce a larger spermatophylax, which suggests that males control the
apportioning of energy reserves during this critical period. It is argued that where energy reserves are required for the production of
a spermatophylax, less energy may be available for calling and so calling strategies should evolve that allow for the more efficient use
of metabolic energy for sound production.


Calling efficiency is a measure of how males convert metabolic energy to sound power. Efficiency was estimated by measuring the
metabolic costs of calling and the power of sound radiation from the calling insect. Metabolic costs of calling in R. verticalis are compared
with those of conehead tettigoniids such as Neoconocephalus robustus where calling appears to require more energy per unit of sound.
The efficiency of conversion of metabolic energy to sound in R. verticalis is 6.4% while that for N. robustus is 2% (Bailey et al. 1993).
Another cost of calling is exposure by the male to acoustically orienting predators. Such predators may include tachinid flies,
insectivorous bats and predaceous females. I discuss experiments where a species of vespertilionid bat is shown to orient to the call of
R. verticalis (Hosken et al. in press). Males may also be subject to cannibalism by orienting females. I describe experiments where females
are released within 2m of calling males and where males show a high degree of female rejection. In the confines of a small container,
where each sex cannot retreat from the other, a male smaller than the female is far more likely to be eaten by the female than males paired
with females of comparable size. In this context, I discuss how male coyness (a reluctance to mate) may be due, in part, to sexual role
reversal and thereby under sexual selection, or due to female cannibalism, and thus selected through survival.

1 aBailey, Winston, J. uhttp://www.jstor.org/stable/3503460?origin=crossref