Calling song and selective phonotaxis in the field crickets,Gryllus firmus andG. pennsylvanicus (Orthoptera: Gryllidae)

The field cricket species, Gryllus firmusand G. pennsylvanicus,occur in a mosaic hybrid zone that roughly parallels the eastern slope of the Appalachian mountains in the northeastern United States. It is important to know what role, if any, the calling song plays in mate choice in sympatric and allopatric populations. In this report, we present results on the variability of calling song properties along transects across this hybrid zone. We also present the results of experiments on phonotactic selectivity of females from an allopatric population of G. firmus.The male calling song of allopatric G. firmuswas significantly slower in temporal rhythm (i. e., chirp and pulse repetition rates) and lower in pitch (i.e., dominant frequency) than that of allopatric G. pennsylvanicus.Calling song properties of males recorded in the hybrid zone varied considerably in temporal and spectral properties. In two-stimulus (choice) phonotaxis experiments, allopatric females of G. firmuspreferred synthetic calling songs with conspecific pulse repetition rates over songs that had lower and higher pulse rates. This preference persisted even when the sound pressure levels of alternative stimuli were unequal. Therefore, allopatric females of G. firmuscan discriminate between conspecific and heterospecific calling songs. Whether or not this same selectivity is present in sympatric populations remains unclear. Investigations of phonotactic selectivity in other allopatric and sympatric populations of both species are currently under way.     

Auditory behaviour of a parasitoid fly (Emblemasoma auditrix, Sarcophagidae, Diptera)

Females of the parasitoid fly Emblemasoma auditrix find their host cicada (Okanagana rimosa) by its acoustic signals. In laboratory experiments, fly phonotaxis had a mean threshold of about 66 dB SPL when tested with the cicada calling song. Flies exhibited a frequency dependent phonotaxis when testing to song models with different carrier frequencies (pulses of 6 ms duration and a repetition rate of 80 pulses s(-1)). However, the phonotactic threshold was rather broadly tuned in the range from 5 kHz to 11 kHz. Phonotaxis was also dependent on the temporal parameters of the song models: repetition rates of 60 pulses s(-1) and 80 pulses s and pulse durations of 5-7 ms resulted in the highest percentages of phonotaxis performing animals coupled with the lowest threshold values. Thus, parasitoid phonotaxis is adapted especially to the temporal parameters of the calling song of the host. Choice experiments revealed a preference of a song model with 9 kHz carrier frequency (peak energy of the host song) compared with 5 kHz carrier frequency (electrophysiologically determined best hearing frequency). However, this preference changed with the relative sound pressure level of both signals. When presented simultaneously, E. auditrix preferred 5-kHz signals, if they were 5 dB SPL louder than the 9-kHz signal.     

The Steppengrille (Gryllus spec./assimilis): Selective Filters and Signal Mismatch on Two Time Scales

In Europe, several species of crickets are available commercially as pet food. Here we investigated the calling song and phonotactic selectivity for sound patterns on the short and long time scales for one such a cricket, Gryllus spec., available as "Gryllus assimilis", the Steppengrille, originally from Ecuador. The calling song consisted of short chirps (2-3 pulses, carrier frequency: 5.0 kHz) emitted with a pulse period of 30.2 ms and chirp rate of 0.43 per second. Females exhibited high selectivity on both time scales. The preference for pulse period peaked at 33 ms which was higher then the pulse period produced by males. Two consecutive pulses per chirp at the correct pulse period were already sufficient for positive phonotaxis. The preference for the chirp pattern was limited by selectivity for small chirp duty cycles and for chirp periods between 200 ms and 500 ms. The long chirp period of the songs of males was unattractive to females. On both time scales a mismatch between the song signal of the males and the preference of females was observed. The variability of song parameters as quantified by the coefficient of variation was below 50% for all temporal measures. Hence, there was not a strong indication for directional selection on song parameters by females which could account for the observed mismatch. The divergence of the chirp period and female preference may originate from a founder effect, when the Steppengrille was cultured. Alternatively the mismatch was a result of selection pressures exerted by commercial breeders on low singing activity, to satisfy customers with softly singing crickets. In the latter case the prominent divergence between male song and female preference was the result of domestication and may serve as an example of rapid evolution of song traits in acoustic communication systems.     

Brain projections and information processing of biologically significant sounds by two large ventral-cord neurons ofGryllus bimaculatus DeGeer (Orthoptera,Gryllidae)

Summary Two ventral-cord neurons in the auditory system ofGryllus bimaculatus were studied electrophysiologically by stimulation with pulses of sound at a single frequency (sine-wave pulses), stridulatory songs, and artificial sounds constructed to imitate the conspecific songs. The sine-wave pulses were varied in frequency, sound intensity, duration, and repetition rate. The stridulatory songs were the conspecific calling, aggressive, and courtship songs and the calling songs of 8 sympatric gryllids (played back at different sound intensities). The artificial songs were varied in carrier frequency, pulse rate, chirp rate, and sound intensity.The LF₁ neuron precisely duplicates the temporal structure of the conspecific calling (and aggressive) song over the whole intensity range (Figs. 7, 8, 10). It is sharply tuned to the carrier frequency of the song (5 kHz) and shows little or no response above 10 kHz and below 3 kHz (Figs. 1, 2). By variation of the calling song's temporal structure it can be demonstrated that the LF₁ neuron is particularly suited to respond to the pulse duration and the pulse and chirp repetition rates of this song pattern (Figs. 6, 9).On the other hand, the HF₁ neuron is a broad-band neuron with a maximal sensitivity at 16 kHz (Figs. 1, 4); it is tuned to the conspecific courtship song with respect to carrier frequency, the short pulse duration, and the very low pulse repetition rate (Figs. 6, 7, 8).The results demonstrate that the two ventral-cord neurons represent highly evolved channels of the auditory pathway in gryllids, each of which transmits important features of the corresponding conspecific songs to several areas of the brain (Fig. 11). But they are not ideal filters for these conspecific songs, since they also respond to many other sound signals (Fig. 10).Supported by the Deutsche Forschungsgemeinschaft as part of the program Sonderforschungsbereich 114 (Bionach), BochumUnder the auspices of the scientist exchange program of the Deutsche Forschungsgemeinschaft and the Academy of Sciences, USSRWe thank Prof. Dr. Schwartzkopff for his help and support; it was due to his initiative and organization that this work could be done in collaboration between the Sechenov Institute, Leningrad, and the Lehrstuhl für Allgemeine Zoologie, Ruhr University, Bochum. We are grateful to Mrs. I. Klotz and Mrs. B. Brücher for technical assistance.     

Temperature Effects on the Temporal Properties of Calling Songs in the Crickets <Emphasis Type="Italic">Gryllus fultoni</Emphasis> and <Emphasis Type="Italic">G. vernalis</Emphasis>: Implications for Reproductive Isolation in Sympatric Populations

Two closely related wood-cricket species, Gryllus fultoni (Orthoptera: Gryllidae) and G. vernalis, produce similar calling songs, consisting of 3-pulse chirps. Analysis of field and laboratory recordings of calling songs showed that, after correction to a common temperature, there was a divergence in chirp and pulse rates between far allopatric populations of G. fultoni and populations sympatric with G. vernalis. To determine whether the divergence in calling songs potentially provides reproductive isolation between G. fultoni and G. vernalis throughout the temperature range over which these insects sing, we recorded calling songs of lab-reared G. fultoni and G. vernalis populations between 18 and 28°C. Mean chirp rate significantly differed between sympatric and far allopatric G. fultoni populations as well as between sympatric G. fultoni and G. vernalis populations. Although there was a significant difference in mean pulse rate between sympatric G. fultoni and G. vernalis populations, pulse rate did not differ between sympatric and far allopatric G. fultoni populations in the laboratory study. Considering the magnitudes of differences in calling song characters discriminated by females of G. fultoni and the mean differences and the variability in calling song characters between the two species, the joint difference in chirp and pulse rates may be adequate for species discrimination over most of the range at which these crickets breed.     

Female life span and fertility are increased by the ejaculates of preferred males

In animals with internal fertilization, sperm competition among males can favor the evolution of male ejaculate traits that are detrimental to females. Female mating preferences, in contrast, often favor traits in males that are beneficial to females, yet little is known about the effect of these preferences on the evolution of male ejaculates. A necessary condition for female preferences to affect the evolution of male ejaculate characteristics is that females select mates based on a trait correlated with ejaculate quality. Previous work has shown that females of the variable field cricket, Gryllus lineaticeps, prefer males that produce calling songs containing faster and longer chirps. In this study, we tested the hypothesis that females receive more beneficial ejaculates from preferred males. Females were placed on either a high- or a reduced-nutrition diet then mated twice to a male of known song phenotype. Females received only sperm and seminal fluid from males during these matings. There was no effect of male song phenotype on any fitness component for females on the high-nutrition diet. Reduced-nutrition females mated to males that produced preferred song types, however, lived longer, produced more eggs, produced more fertile eggs, and had a higher proportion of their eggs fertilized than those mated to other males. The life-span benefit was positively associated with male chirp duration, and the reproductive benefits were positively associated with male chirp rate. We explored two possible mechanisms for the life span and reproductive benefits. First, a path analysis suggested that part of the effect of male chirp duration on female life span may have been indirect; females mated to males that produced longer chirps showed delayed oviposition, and females that delayed oviposition lived longer. Males that produce longer chirps may thus transfer fewer or less potent oviposition stimulants to females in their seminal fluid. Second, there was a positive correlation between male chirp rate and the number of sperm transferred to females. The fertility benefit may thus have resulted from females receiving more sperm from males that produce faster chirps. Finally, there was a negative phenotypic correlation between male chirp rate and chirp duration, suggesting that females may have to trade off the life span and reproduction benefits when selecting a mate.     

Filtering of temporal parameters of the calling song by cricket females of two closely related species: a behavioral analysis

The phonotactic response of cricket females was investigated on a locomotion compensator to determine the temporal parameters of the male's calling song which are important for species recognition. Two sympatric species (Teleogryllus commodus, T. oceanicus) that show different syllable periods in the chirp and trill parts of their calling songs were used. By their responses T. commodus females exhibited two temporal filters for syllable periods, which were tuned to the species-specific syllable periods occurring during chirp and trill. For song recognition both filters had to be activated and for both a minimum number of three to five consecutive syllable periods was necessary. In contrast, T. oceanicus females showed only one sharply tuned filter corresponding to the chirp part of the male's calling song. This filter was sufficient for calling song recognition. Syllable periods of the trill part also influenced calling song recognition, but these played only a minor role. Carrier frequency was also important for positive phonotaxis. Calling song recognition by T. commodus females is largely based on central nervous processing, while for T. oceanicus both peripheral frequency filtering and central temporal filtering is important. Accepted: 17 January 1997     

两种米纹蝗雄性鸣声的比较研究(直翅目,蝗总科)

应用计算机技术分析了红足米纹蝗Notostaurus rubripes Mistshenko和小米纹蝗Notostaurus albicornis albicor-nis(Ev.)雄性的鸣声特征。这两种米纹蝗雄性呜叫声的脉冲组持续时间、脉冲组组份、脉冲组间隔、频率的主能峰以及呜叫行为均具有显著差异,可作为2种米纹蝗的分类依据。红足米纹蝗雄性鸣声的脉冲组间隔约为0．647s,每一脉冲组持续时间约为0．0673s,每个脉冲组有8个脉冲串,每个脉冲串仅有1个单脉冲,鸣声的主能峰频率约3．86～5．64kHz。小米纹蝗雄性鸣声的脉冲组间隔约0．529s,每一脉冲组持续时间为0．1185s,每个脉冲组有8个脉冲串,每一脉冲串有1～6个单脉冲构成,主能峰频率约8．10～9．24kHz。     

The calling song of the field cricket,Gryllus bimaculatus (de geer): constraints on transmission and its role in intermale competition and female choice

Field studies of calling male field crickets, Gryllus bimaculatus, showed that males formed calling aggregations. Within aggregations males appeared to maintain an exclusive female-attraction zone about their burrows; calling song may thus serve as an aggressive signal to neighbouring males to maintain spacing. Calling song attenuates with distance. Furthermore, calls became degraded with distance by the loss of low frequency components and a reduction in the interval between chirps and pulses due to reverberation. Playback experiments suggested that the predictable degrading properties of the call may serve as a distance-finding mechanism maintaining observed male spacing. The intensity of calls and the repetition rate of chirps and pulses was positively correlated with male size. While information contained within the intensity parameter of calls may prove unreliable due to unpredictable attenuation and irregular amplitude fluctuations, the repetition rate of chirps and pulses was not affected by distance degradation. Playback experiments in which intensity was controlled suggested that females orientate preferentially to the calls of large males.     

历山自然保护区四种蟋蟀鸣声结构的比较研究(直翅目:蟋蟀总科)

应用计算机技术,分析了山西历山自然保护区的白须双针蟋,短翅灶蟋,银川油葫芦,迷卡斗蟋4种蟋蟀雄性的鸣声结构,白须双针蟋雄性鸣声的每个脉冲组持续时间和每个脉冲组的脉冲数不同,主能峰频率为6．5kHz,短翅灶蟋雄性鸣声的时域波形较规则,每个脉冲组由3个脉冲构成,每个脉冲组的持续时间,脉冲组间隔基本相同,主能峰频率6．6kHz,银川油葫芦雄性的鸣声由两类脉冲组构成,主能峰频率为3．94kHz,迷卡斗蟋雄性鸣声的时域波形较规则,每个脉冲组由6－7个脉冲构成,主能峰频率为3．86kHz。     

Behavioral response ofGraminella nigrifrons (Homoptera: Cicadellidae) to experimentally manipulated vibrational signals

Mate recognition for the leafhopper Graminella nigrifrons(Forbes) occurs when a male spontaneously emits a multisectional vibrational calling song to which females respond by emitting simple pulses. Significant differences were found among males in the duration, number of chirps, and chirp rate within sections of the song and the total song. Repeatability (proportion of total variation due to differences among males) of call features ranged from very low (0.04 for total chirps in song) to high (0.67 for section 3 chirp rate). However, song modification and playback experiments revealed that the variation in the measured song features was not important in determining whether a female will respond. Rather, female response depended only on the presence of two of the three types of pulses which comprise a chirp. These essential pulses were found within chirps of all call sections that contain chirps. Manipulation of chirp rates from 0.58 to 2.70 times the normal rate did not affect female response, nor did changing the period of silence between the essential pulse types from 0.25 to 1.75 times the normal period. These results suggest that components of the male calling song function in mate recognition but are not used by females to discriminate among conspecific males.     

CALLING SONGS OF FIELD CRICKETS (TELEOGRYLLUS OCEANICUS) WITH AND WITHOUT PHONOTACTIC PARASITOID INFECTION

The field cricket Teleogryllus oceanicus has been introduced to Hawaii, where it is parasitized by an acoustically orienting parasitoid fly, Ormia ochracea. Previous work showed that call parameters from parasitized populations differ from those in unparasitized populations in a direction expected if selection by flies is occurring. Here we examined songs of males collected in the field and compare calling song characters of crickets later found to harbor parasitoid larvae with those of males free of parasitoids. The two groups differ significantly in several song characteristics, particularly the trill-like long chirp given at the beginning of each song. Males with longer long chirps containing shorter interpulse intervals are more likely to be parasitized, suggesting that the flies find such males more attractive. Depending on the traits females prefer, sexual selection may oppose natural selection in altering T. oceanicus song in parasitized populations.     

Female recognition of trills in the male calling song of the field cricket,<Emphasis Type="Italic"> Teleogryllus taiwanemma</Emphasis>

The calling song of the field cricket, Teleogryllus taiwanemma, is usually considered to consist of sequences of separate chirps. However, sometimes it comprises a phrase of several chirps in a row, with one long chirp (chirp) and a few short chirps (trills). In this study, I compared the phrase containing only chirps with that containing both chirps and trills by analyzing male songs and conducting playback experiments of male songs to females. The song analyses showed significant differences between chirps and trills for all song parameters except bandwidth. To test whether female preference differed with respect to the two phrases, I performed two-speaker playback experiments. When the same numbers of phrases were presented per unit time, females preferred the song with trills to that without trills. This result may reflect female preference for songs with greater sound density. In subsequent playback experiments, I equalized the total sound duration per unit time (duty cycle) in songs with and without trills. The numbers of females that preferred songs with and without trills did not differ significantly. This suggests that trills can attract females like chirps do, even though the two sounds have different components.     

四种蝗虫雄性鸣声的比较研究(直翅目,蝗总科)

应用计算机技术分析了肿脉蝗Stauroderus scalaris scalaris(Fischer-Waldheim)、宽须蚁蝗Myrmeleotettixpalalis(Zubowsky)、邱氏异爪蝗Euchorthippus cheui Hsia、西伯利亚蝗Aeropus sibiricus(Linnaeus)雄性的鸣声特征.这4种蝗虫雄性鸣声特征差异显著.肿脉蝗雄性鸣声具有脉冲序列的分化,每个脉冲序列分为两种不同的脉冲组,第1种脉冲组持续时间约0.081 s,有7个脉冲串组成,每个脉冲串有7个单脉冲构成;第2种脉冲组持续时间不等,有13～18个脉冲串组成,脉冲串持续时间为0.021 s,间隔为0.010 s.鸣声的主能峰频率约8.62 kHz.宽须蚁蝗雄性鸣声的脉冲组持续时间为0.23 s,脉冲组间隔为0.35 s,每个脉冲组由28～31个单脉冲组成,主能峰频率为6.89 kHz、12.75 kHz.邱氏异爪蝗雄性鸣声的脉冲组持续时间为0.22 s,脉冲组间隔为0.76 s,每个脉冲组由6～7个脉冲串组成,每个脉冲串内含有1～5个单脉冲,主能峰频率为9.65 kHz.西伯利亚蝗的脉冲组持续时间约为0.092 s,脉冲组间隔为0.08 s,每个脉冲组分化为5～6个脉冲串;主能峰频率为7.58 kHz.     

Temperature coupling in cricket acoustic communication

Summary Temperature effects on calling song production and recognition were investigated in the North American field cricket, Gryllus firmus. Temporal parameters of field-recorded G. firmus calling song are strongly affected by temperature. Chirp rate and syllable rate increase, by factors of 4 and 2, respectively, as linear functions of temperature over the range in which these animals sing in the field (12°–30 °C). Temperature affects syllable duration to a lesser extent, and does not influence calling song carrier frequency. Female phonotactic preference, measured on a spherical treadmill in the laboratory, also changes with temperature such that warmer females prefer songs with faster chirp and syllable rates. Best phonotaxis, measured as accuracy of orientation to the sound source, and highest walking velocity, occur in response to temperature-matched songs at 15°, 21°, and 30 °C. Experiments under semi-natural conditions in an outdoor arena revealed that females perform phonotaxis at temperatures as low as 13 °C. Taken together, the song and phonotaxis data demonstrate that this communication system is temperature coupled. A strategy is outlined by which temperature coupling may be exploited to test hypotheses about the organization of neural networks subserving song recognition.Abbreviations CP chirp period - SP syllable period - SD syllable duration     

Sexual differences in cricket calling song recognition

Summary Phonotactic behavior was studied in male crickets,Teleogryllus oceanicus. Tethered flying males were presented with electronically synthesized calling song models in a two-choice phonotaxis assay, and their song preferences were determined and compared with previous findings for females.Males are poorer at discriminating between songs than females; they do not display choice behavior as frequently as females, and the choices they do make are not as consistent as those of females (Figs. 3, 4). T. oceanicus calling song is composed of rhythmically different chirp and trill sections. The selectivity of males for these two components differs from that of females. Females prefer chirp to trill, but the opposite is true for males (Fig. 5B-F). Males are similar to females in that they prefer either a conspecific song model or its separate components to a heterospecific model (Fig. 5A, G, H).Behavioral and neural implications of these findings are discussed.     

Spatial distribution, calling and interspecific acoustic interactions in two species of the Australian tettigoniid genus Tympanophora (Orthoptera, Tettigoniidae)

Two species of the Australian genus Tympanophora, Tympanophora new species 1 ( T.n.sp.l) and T. similis share the same habitat and are sympatric with several other bushcricket species. Males of T. similis call in aggregations, whilst males of T.n.sp.l frequently sing closer to heterospecific than to conspecific neighbours. Hence males of T.n.sp.l may have to cope with more severe problems of interspecific acoustic interference than males of T. similis. Laboratory experiments support field data which indicate that the number of calling T.n.sp.l males decreases when the number of singing males of T. similis increases. Acoustic interactions between the two species and sympatric bushcricket species occur in the laboratory. Heterospecific song affects chirp interval and/or chirp pattern in the two Tympanophora species. Males of T.n.sp.l respond to the song of the sibling species T. similis differently than to the calls of the more distantly related tettigoniids tested. However, the response of T. similis males appears to depend on the temporal structure of the heterospecific songs. The results do not suggest that the frequency content of the heterospecific calls is important for the song interference which has been observed in Tympanophora.     

Temporal pattern changes in the calling song of the katydidMygalopsis marki Bailey in response to conspecific song (Orthoptera: Tettigoniidae)

Males of Mygalopsis markiBailey (Tettigoniidae: Orthoptera) alter the temporal structure of their song in response to other competing males. The song of males calling in aggregations has a high variance in the number of syllables per chirp, with short intervals between each chirp. In contrast, the temporal pattern of the song of isolated males is more evenly spaced, with an increase in length of the interchirp intervals and low variance in the number of syllables per chirp. In order to simulate a calling male moving closer to a male in an aggregation, a playback technique was adopted whereby the recorded calling song of a male was presented to itself via a loudspeaker in increments of 2dB. The change in song pattern of the resident male involved a reduction in the number of syllables per chirp and an increase in the interchirp interval, with the number of chirps per second remaining constant. This reduction in the output of the song, instead of not calling as a result of an acoustic contest, may still allow males to continue calling for females.     

Prolonged response to calling songs by the L3 auditory interneuron in female crickets (Acheta domesticus): possible roles in regulating phonotactic threshold and selectiveness for call carrier frequency

L3, an auditory interneuron in the prothoracic ganglion of female crickets (Acheta domesticus) exhibited two kinds of responses to models of the male's calling song (CS): a previously described, phasically encoded immediate response; a more tonically encoded prolonged response. The onset of the prolonged response required 3-8 sec of stimulation to reach its maximum spiking rate and 6-20 sec to decay once the calling song ceased. It did not encode the syllables of the chirp. The prolonged response was sharply selective for the 4-5 kHz carrier frequency of the male's calling songs and its threshold tuning matched the threshold tuning of phonotaxis, while the immediate response of the same neuron was broadly tuned to a wide range of carrier frequencies. The thresholds for the prolonged response covaried with the changing phonotactic thresholds of 2- and 5-day-old females. Treatment of females with juvenile hormone reduced the thresholds for both phonotaxis and the prolonged response by equivalent amounts. Of the 3 types of responses to CSs provided by the ascending L1 and L3 auditory interneurons, the threshold for L3's prolonged response, on average, best matched the same females phonotactic threshold. The prolonged response was stimulated by inputs from both ears while L3's immediate response was driven only from its axon-ipsilateral ear. The prolonged response was not selective for either the CS's syllable period or chirp rate.     

The Influence of Substrate on Male Responsiveness to the Female Calling Song in Nezara viridula

The female calling song (FCS) of the southern green stink bug Nezara viridula is composed of vibrational pulse trains that include either short pulses and a long pulse (FCS-1) or just short pulses (FCS-2). Their function in communication was studied by investigating male vibratory responses to natural and artificial signals on artificial and natural substrates. On a loudspeaker membrane, FCS-1 triggered in males from a Slovene and a French population significantly more courtship songs (MCrS) than FCS-2. Experiments with artificial signals showed that male responses are modulated by the duration of pulse trains and pulse repetition time. On a bean plant, males of both populations responded in the same way to the two types of female calling song pulse trains. Moreover, a laser vibrometer study of the transmission of different natural and artificial vibratory signals through the bean plant showed that the pulses of a high repetition rate are prolonged and fused at distances from the emitter. We conclude that female calling song pulse trains of different temporal structure have the same function in vibrational communication of the species. The temporal and spectral structures of the female calling songs of N. viridula are discussed in terms of effective transmission through plants.