Chirp Duration Research Articles

Female preference for symmetric calls in a grasshopper

Grasshoppers produce calls by alternating use of a row of pegs on the two hind legs. The number of pegs per row in the grasshopper Myrmeleotettix maculatus demonstrated fluctuating asymmetry as shown by signed right-minus-left number of pegs having a frequency distribution not differing from a normal distribution with a mean value of zero. Peg asymmetry was significantly negatively related to mean number of pegs per leg. Peg asymmetry was relatively larger than asymmetry in femur length. A larger degree of peg asymmetry resulted in a larger degree of asymmetry in maximum frequency of chirps and asymmetry in the duration of chirps produced by the two legs. Calls produced by males with experimentally manipulated numbers and asymmetries of pegs were used in a female phonotaxis experiment. Females preferred calls of males with a larger and more symmetrical number of pegs. Peg asymmetry differed in a field sample of mated and unmated males with mated males having a smaller degree of peg asymmetry. These results demonstrate that females can discriminate male asymmetry directly on the basis of calls.

A wireless spread-spectrum communication system using SAW chirped delay lines

We report on the use of broad-band chirp signals for spread-spectrum communications in indoor and industrial environments. The well-known pulse compression technique associated with chirp signals is exploited to achieve a highly robust communication system. For the generation and compression of the chirp signals, surface acoustic wave delay lines fabricated from an LiTaO/sub 3/-X112rotY substrate are used. Center frequency, bandwidth, chirp duration, and chirp rate are 348.8 MHz, 80 MHz, 500 ns, and /spl plusmn/40 MHz//spl mu/s, respectively. Different modulation schemes for chirp signals are introduced, the effects of nonlinearities, frequency drift, and temperature drift are addressed, and simulations and measurement results from a hardware demonstrator are presented for the use of /spl pi//4-differential quadrature phase-shift keying (DQPSK) modulation. A data rate of up to 40 Mb/s has been achieved experimentally and shows that the proposed system is highly robust against multipath effects.

The importance of calling song and courtship song in female mate choice in the variable field cricket

Male field crickets produce calling songs, courtship songs, tactile signals and chemical signals. Although calling songs are known to play an important role in female mate choice, the importance of the other signals in mate choice is poorly understood. In the variable field cricket, Gryllus lineaticeps, females select mates, in part, based on variation in male calling song. Females prefer higher chirp rates, a trait which is partially dependent on male nutrient intake, and females prefer longer chirp durations, a trait which appears to be independent of male nutrient intake. We tested whether females also have preferences based on variation in male courtship song, and whether the structure of male courtship song varies with nutrient intake. First, we reexamined female preference for calling song chirp rate. Then, we examined: (1) female preference based on courtship song chirp rate; (2) the relative importance of calling song and courtship song chirp rate; (3) the nutrition dependence of courtship song chirp rate; and (4) the correlation between calling song and courtship song chirp rate. As reported previously, females preferred higher calling song chirp rates, and in addition, preferred higher courtship song chirp rates. Females were more likely to switch from a speaker broadcasting more attractive calling song to a speaker broadcasting less attractive calling song when the attractive calling song was associated with an unattractive courtship song than when it was associated with an attractive courtship song. Preferences based on courtship song may thus cause females to alter the choices that they made based on calling song. Males that received greater nutrients did not produce higher courtship song chirp rates. There was no correlation between calling song and courtship song chirp rate. As a result, the two traits may provide information to females about different aspects of male quality.

Nutritional effects on male calling behaviour in the variable field cricket

In the variable field cricket,Gryllus lineaticeps, females prefer higher chirp rates and longer chirp durations in male calling song. Higher chirp rates are energetically more expensive to produce, but the energetic cost of calling does not vary with chirp duration. We tested the hypothesis that nutrition affects male chirp rate and chirp duration. Full-sibling brothers of similar age were placed on high- and low-nutrition feeding regimes. There was no effect of feeding regime on male weight; neither group showed a significant change in weight, and the two groups did not differ from each other in weight change. However, males on the high-nutrition feeding regime both called more frequently and called at higher chirp rates when they did call. The two groups did not differ in chirp duration, the duration of pulses within chirps or chirp dominant frequency. These results suggest that females select mates based on one nutrition-dependent call character (chirp rate) and one nutrition-independent call character (chirp duration). In addition, because males in the two groups did not show significant differences in weight change, and because males on the high-nutrition feeding regime engaged in energetically more expensive calling, these results suggest that males invest any excess energy above their basic maintenance requirements in the production of call types that increase their attractiveness to females. The absence of a relationship between body condition and calling song structure for males in the field may be a consequence of this pattern of energy allocation.

Tracing the phase distortion of a single ultrashort light pulse from angularly resolved second-harmonic autocorrelation

We implement for the first time the frequency tracer based on the second-harmonic autocorrelator able to measure pulse duration and instantaneous frequency of a single ultrashort light pulse. This tracer is used to characterize femtosecond pulses from a Ti:sapphire CPA system. The data on chirp and pulse duration are in good agreement with the estimations of dispersion at the system output. We show by computer simulation that the second-harmonic autocorrelator is able to trace quadratic (linear chirp), fourth and other even orders of phase distortions. Computed images directly reproduce the phase distortions and no mathematical algorithm is required for phase retrieval.

The energetic cost of calling in the variable field cricket, Gryllus lineaticeps

Abstract. Female preferences for conspicuous male calls have been documented in many groups. However, relatively few studies have examined the metabolic costs associated with the production of call types preferred by females. We measured the oxygen consumption of calling male Gryllus lineaticeps Stål crickets using closed chamber respirometry. Calling song was recorded concurrently. The average increase in mass‐specific oxygen consumption during calling was 2.7 times basal rates of oxygen consumption, and calling males consumed approximately 1.2ml O2g‐lh‐1. Oxygen consumption increased with increasing chirp rate and pulse duration, but not with increasing chirp duration. Females of this species prefer higher chirp rates, thus some call types that increase the male's attractiveness to females require more metabolic energy to produce.

Discovery of Male Acoustic Signals in the Greenhouse Whitefly, Trialeurodes vaporariorum (WESTWOOD) (Homoptera: Aleyrodidae)

Courtship-like signals produced by males during mating behavior were recognized for the first time in whiteflies. Synchronous audio-video recordings ascertained that sexually matured males of Trialeurodes vaporariorum (WESTWOOD) produced substrate-borne vibrations by rapidly oscillating their abdomens in a stereotyped rhythm accompanied with a short moving action around the female. Signals were consisted of a sequence of discrete bouts of sounds, and were named "chirps." A chirp was composed of a series of sinusoidal waves divided into several sections called "pulses." A chirp was composed of a series of sinusoidal waves divided into several sections called "pulses." A pulse was defined as having a bimodal phase. Pulse intervals varied from 19.9 to 25.8 ms distinguished by small waves of low amplitude. A chirp was composed of 10-20 pulses, varying in number in the courtship progress. Chirp durations varied from 0.62 to 1.44 ms in proportion to the pulse number. Chirp intervals showed no periodicity, varying from 2.45 to 14.4 s. At the final male courting behavior, a persistent, periodically placed wing flicking was substituted for the train of chirps. Prolonged courtship behavior might be due to the necessity of sexual stimulation for female by repeated emission of the male acoustic signals as well as his persistent wing flicking.

Convergent song preferences between female field crickets and acoustically orienting parasitoid flies

Traits that increase the attractiveness of males to females often make them more conspicuous to predators. In the field cricket (Gryllus lineaticeps), males are attacked by parasitoid tachinid flies (Ormia ochracea) that locate males through their calls. Female flies larviposit on crickets and the larvae burrow into and feed on the cricket, killing the cricket upon emergence. To determine whether traits preferred by females increase a male's risk of attracting a predator, I examined the effect of variation in male singing behavior on mate and predator attraction. Both female crickets and female flies preferred male calling songs with higher chirp rates, longer chirp durations, and higher chirp amplitudes. In addition, both female crickets and female flies preferred male calling songs with higher chirp rates and longer chirp durations, even when these songs were of lower amplitude. These results suggest that sexual selection by female choice will favor the evolution of higher chirp rates and longer chirp durations. However, call types that increase a male's attractiveness to females also appear to increase a male's risk of attracting parasitoids. Sexual and natural selection appear to have opposing effects on the evolution of male singing behavior in this species.[Behav Ecol 7: 279-285 (1996)]

Natural variation in the temporal patterning of calling song structure in the field cricket Gryllus pennsylvanicus: effects of temperature, age, mass, time of day, and nearest neighbour

Genetic and environmental sources of variation in the temporal patterning of song structure may be important variables influencing male field cricket reproductive success. Song structure in both field and laboratory populations of Gryllus pennsylvanicus was examined to assess possible sources of variation. Factors examined included temperature, male age, body mass, time of day, and male spacing patterns. Temperature was positively correlated with pulse rate and negatively correlated with interchirp interval for both field and laboratory populations. Temperature was negatively correlated with chirp duration only in the field population. Calling song structure did not vary with male age or mass. Time of day had a significant effect on the song parameters examined, even when data were corrected for temperature differences. Males calling in the morning had faster pulse rates and shorter chirp durations than males recorded at night time. Male spacing patterns also influenced calling; isolated males had longer intervals between consecutive chirps than clumped males. Data are discussed in terms of acoustical competition between males and female choice.

Song Variability and the Response To Conspecific Song and To Song Models of Different Frequency Contents in Males of the Bushcricket Requena Verticalis (Orthoptera: Tettigoniidae)

AbstractVariability in the temporal structure of the song has been investigated for the Australian bushcricket Requena verticalis (Listroscelidinae: Tettigoniinae: Orthoptera). Chirp interval and chirp duration of an individual male vary between two days. Males differ in their readiness to call. Sporadic singers sing consistently only in the presence of another calling conspecific or when acoustically stimulated, while steady singers call readily under acoustic isolation. Sporadic as well as steady singers change their chirp interval in the presence of another calling conspecific. Steady and sporadic singers are able to differentiate between 16 and 28 kHz, the two main frequency components of the song. There is evidence that the effect of the natural song on the temporal pattern of the call may be due to the 28 kHz frequency component. Individual variation in the temporal parameters is within 0.1 s, and the changes caused by acoustic stimulation are of similar magnitude. Further studies are necessary to evaluate if males and/or females uses these differences to discriminate between conspecifics.

Disturbance Sounds of Adult Passalid Beetles (Coleoptera: Passalidae): Structural and Functional Aspects1

I Ann. Entorno). Soco Arn. 76: 6-22 (1983) Stridulatory apparatus, method of sound.production, and disturbance chirp duration, chirp interval, chirp intensity, and resonant oscillation have been studied in 17 species of passalid beetles (Coleoptera: Passalidae). These species were, the North American Odontotaenius disjunctus (IlIiger); the Mexican O. zodiacus (Truqui), Heliscus tropicus (Percheron), Oileus rimator (Truqui), Spurius halffteri Reyes- Castillo, Petrejoides orizabae Kuwert, Verres hageni Kaup, Proculejus brevis (Truqui), Pseudacanthus mexicanus (Truqui) , and Passalus (Pertinax) punctatostriatus Percheron; and the African Didimus alvaradoi Corella, D. latifrons Corella, D. nachtigali (Kuwert), Erionomus pilosus Aurivillus, E. planiceps (Eschscholtz), Pentalobus barbartus (F.) and P. savagei (Percheron). Stridulatory apparatus is abdomino-alary, with specialized afeas of abdominal tergum 6 (pars stridens) rubbing against a restricted afea of each metathoracic wing (plectrum). Disturbance sound is due to friction of the ab- dominal pars stridens against the plectrum in the metathoracic wings. Structures thrown into the resonant oscillation by the stridulatory organs are the wings, which bear rows of spines on their underside. physical aspects of sound produced by the adults. These are the contributions of Park (1937), and Alexander et al. (1963) using O. disjunctus, of Baker (1967) using three species ofPentalobus, of Miller (1971) using P. barbatus, and of Meyer-Rochow (1971) using A. ed- entulus and P. dilatatus. Concerning the structure of the sound and the behav- ioral contexts in which the sounds are produced, the

Song recognition and song pattern in a shorthorned grasshopper

1. Computer generated, artificial songs (Fig. 1) were played to grasshoppers of the gomphocerine speciesOmocestus viridulus L. in a temperature-regulated, echo-reduced chamber (Fig. 2). The animals often responded by singing their response song, and the occurrence of response songs was used to indicate the animals' preference for the artificial songs. At various temperatures, the chirp duration and impulse rate preferred by the animals were determined and compared with the magnitudes of these parameters in the response songs. 2. The duration of the response songs decreases with temperature (Fig. 5), and so does the chirp duration (Fig. 3). The chirp rate (which in this species is the reciprocal of the chirp duration) decreases during a response song (Fig. 6). 3. In the first experiments the chirp duration was varied in the artificial songs, while the ratio chirp rate to impulse rate was kept constant (as in the natural songs). The preferred chirp duration changes more with temperature than does the chirp duration of the response songs (Fig. 3). At all temperatures, songs with chirp durations half or double of the preferred one could also release a response song. The animals even responded to chirp durations outside the natural range (Fig. 3). 4. In the second experiments, the chirp rate (C) and impulse rate (I) at 28 °C (C28 and I28) and 38 °C were combined into four different songs: C28I28, C38I38, C28I38 and C38I28. The former two songs correspond to the natural songs at 28 ° and 38 °C, whereas the latter ones are artificial. The temperature of the listening animals was also varied. The choices made by femal grasshoppers showed that the chirp rate is the major parameter and the impulse rate the minor parameter in determining the acceptance of a song. 5. Four different criteria for measuring the female song discrimination were compared: (a) the behavioural threshold (i.e. the sound level of an artificial song which is just sufficient for response songs to be released in the females), (b) response or no response, (c) the number of response songs in a response, and (d) whether the response was given to the 1st, 2nd or 3rd song presentation. (a) was more sensitive than (b), and both gave rather similar results. In (c) and (d) the responses appeared to be independent of the type of songs presented. 6. The behavioural threshold increased before and decreased after egg deposition (Fig. 7).

A comparison of the origin and temporal arrangement of pulsed sounds in the songs of the Grasshopper and Sedge warblers, Locustella naevia and Acrocephalus schoenobaenus

The songs of the two British warblers Locustella naevia and Acrocephalus schoenobaenus were examined by means of oscillographic recordings. Both songs are composed of pulsed elements arranged in rhythmical successions. The song of L. naevia is simple and stereotyped consisting of a succession of paired pulses with a repetition frequency of 26 Hz. The song of A. schoenobaenus contains many different phrases each consisting of a succession of identical chirps. Chirps consist of successions of pulses, the number and repetition rate of which vary from phrase to phrase.The songs are discussed in relation to the physiology of sound production and to the way in which information is encoded into sound signals. It is proposed that pulses are produced by the syringeal muscles, whilst the rhythm, tempo and duration of chirps and phrases are controlled by the respiratory muscles. A distinction is drawn between the action of the extrinsic syringeal muscles, which may produce low frequency pulses, and the intrinsic syringeal muscles, which may produce high frequency pulses.The codal format in both songs is shown to be highly redundant, being based on the repetition of identical units of information. This device reduces the possibility of distortion of meaning by interference from environmental noise but limits the information carrying capacity of the code. The method of pulse coding is shown to be particularly well suited to the avian auditory system which is adapted to receiving and processing rapid transient signals. This ability is in part attributable to the fine discrimination of time and amplitude changes in the cochlea.

Phonotactic behavior of crickets

Comparative study of phonotactic reactions of females of 5 species of crickets to the calling song (CS) of conspecific males and different sound models in Y-maze experiments showed: 1. InGryllodinus kerkennensis the essential property of the signal is the continuity of the song (Fig 3). 2. InGryllus campestris andG. bimaculatus pulse rate and chirp duration are important, the former having narrow and the latter broad tuning of reaction to chirp duration (Fig. 4). 3. InSpecies 2 (see Methods) chirp rate and pulse duration determine the specific response of females (Figs. 5 and 6). 4. InMelanogryllus desertus the most important parameters are the mean pulse rate and the increase in amplitude of pulses within the chirps (Fig. 7). 6. The spectrum of the CS is not important for the process of recognition as far as it falls into the tuning curve of specialized low-frequency channel of the auditory system. High-frequency sounds outside the range of this channel are not effective even if they have the same amplitude modulation pattern as the CS.

A pulse-compression echo sounder for ocean bottom surveys

A pulse-compression echo sounder (PCES) has been developed and used in two ocean bottom surveys. The PCES transmitted a chirp signal, i.e., a frequency-modulated signal, instead of a gated sine wave. The returned echo was correlated with the stored replica of the transmitted signal in the polarity coincidence Deltic correlator. The bandwidth of the chirp signal was 1.6 kc/s centered at 12 kc/s. The chirp duration was 20 msec, the peak power during the pulse was 800 watts, and the pulse-compression ratio was 32:1. The results show that the system provides (1) a fine resolution of closely spaced bottom and sub-bottom surfaces in the deep ocean, (2) improvement in signal-to-noise ratio over the conventional echo sounders, and (3) sub-bottom penetration of up to 30 meters and a qualitative indication of the bottom surface roughness. Typical sections of the data are given.