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Anthropophony is a prominent component of soundscapes worldwide and is known to impact biota. While responses to anthropophony in terrestrial and marine animals have been relatively well-studied, there is still a lack of knowledge regarding freshwater animals. In fact, freshwater taxa are among the possibly most threatened groups, and unveiling the reasons for their threat is crucial. We investigated the effect of low-frequency sounds -usually associated with anthropophony- on the stridulation of Krizousacorixa femorata, a common water bug in Mexico City. Using aerial recordings, we estimated the Normalized Difference Soundscape Index (NDSI), which is the most commonly used index to measure anthropophony, to characterize soundscapes in six city sites throughout the year. Additionally, from underwater recordings in the same sites, we obtained the peak frequency (Pf) of the stridulations, as it is the frequency with the highest energy and, therefore, the one that can travel the farthest and can be identified even in the presence of overlapping sounds. Finally, we evaluated the relationships between soundscapes and Pf through a mixed linear model. There was a negative correlation between NDSI and Pf, indicating higher-pitched stridulations at sites with dominant anthropophony. While we cannot rule out other factors contributing to stridulation variation, we remain uncertain about how low-frequency sounds impact freshwater ecosystems and the intricate relationship between soundscapes and aquatic life in urban settings. Implications for insect conservation: There is a correlation between anthropophony and variations in the stridulation of aquatic bugs. This highlights the possibility of sound pollution on freshwater systems, emphasizing the need for assessment to better understand and prevent potential harm to aquatic insects. [ABSTRACT FROM AUTHOR]

Sound production in Passandridae is discovered and the involved structures are described and illustrated using scanning electron microscopy (SEM), revealing a single type of stridulatory apparatus. The phylogenetic significance of this newly described mechanism is discussed based on a finely detailed analysis of representatives from 8 of 9 passandrid genera as well as from five closely related families, which allows hypothesizing the presence of a prosterno-coxal stridulatory apparatus as a unique synapomorphy of the clade comprising all passandrid genera except Aulonosoma Motschulsky. A note on the sound generation mechanism and behaviour is also provided. [ABSTRACT FROM AUTHOR]

Blue catfish Ictalurus furcatus, the largest catfish in North America and an invasive species in Chesapeake Bay estuaries, has experienced explosive population growth, negatively impacting native species. They have strong pectoral spines that can be locked and rubbed against the pectoral girdle to produce stridulation sounds although sound production during behavioral interactions is unstudied. We examined agonistic behavior in juveniles by allowing individuals to establish a territory and introducing an intruder. Big (43–50 cm total length) and small (36–41 cm) fish were paired within and across size ranges. Territory was considered established when a fish remained in its shelter for over an hour. Fish typically entered the shelter head first and maintained that orientation. They used a variety of agonistic behaviors in shelter defense including aggressive contact, caudal sweeping, and standoff but not the production of stridulation sounds. Individuals often utilized different behaviors indicating less stereotypy than in many fishes, and there were differences in incidence of behaviors between big and small fish. Residents and larger fish did not always win, perhaps due to juvenile status and low fitness consequences of territorial possession. [ABSTRACT FROM AUTHOR]

Strident lobsters of the Palinuridae family emit sounds in the presence of predators that can be used in the acoustic monitoring of such species. This study aims to identify sound emission and describe the structures of sound mechanism in red (Panulirus meripurpuratus) and green (Panulirus laevicauda) Brazilian spiny lobsters. The lobsters were collected in the environment, and recordings were performed in laboratory tanks with submerged hydrophones. The animals were stimulated to emit sound by the presence of an artificial octopus in the tank. The sounds emitted by the lobsters were analyzed by means of the waveform, and the structures involved (plectrum and file) were observed using scanning electron microscopy (SEM). Both species emitted a rasp sound composed of several pulses, with a rate varying from 125 to 265 pulses per second. The SEM showed that the file is similar between the species and it is covered by microscopic plates (shingles) measuring between 12.6 and 12.9 μm of medial–lateral width and 6.2 μm and 7.1 μm of anteroposterior length. This analysis also revealed for the first time the presence of pores (< 1 μm in diameter) with vestiges of cuticular setae in-between the shingles, which could be involved in the mechanosensory control of sound production in lobsters. The results of this study corroborate the morphological pattern of sound emission structure described for other lobsters of the genus Panulirus. [ABSTRACT FROM AUTHOR]

In katydids (Orthoptera: Tettigonioidea) of the subfamily Phaneropterinae females ready to mate initiate a duet, announcing her position to the male singer, but also potentially to eavesdropping rivals. In many species the male seems to defend the communication by adding self-produced imitations of a female response. If these signals occur within the male sensory time-window after the female song, they can disturb the orientation of rivals. In two species of the genus Gonatoxia, males and females use short, relatively narrow-banded sounds (width 2-7 kHz 10 dB below peak). Male song and female response, however, differ considerably in peak frequency. In G. maculata, the peak frequency of the last part of the male song (13 kHz) is between that of the first part (15 kHz) and the female response (9 kHz), in G. helleri the last part (9 kHz; assumed imitation) and the female song are identical in peak frequency and by a factor two lower than the first part (19 kHz). The male stridulatory file of this species is correspondingly modified and differs from all other members of the genus. The imitation of spectral properties of the female response is not known from any other katydid. [ABSTRACT FROM AUTHOR]

Mating behaviour of four species of pill-millipedes under genus Arthrosphaera Pocock ( Arthrosphaera dalyi Pocock and Arthrosphaera disticta Pocock, Arthrosphaera fumosa Pocock and Arthrosphaera magna Attems) endemic to the Western Ghats of Southern India was analyzed in mesocosms. Stridulation is a classical communication signal in males as well as females for mate selection. Conglobation (or volvation) is a mechanism of defence to protect from disturbance or avoid predation. If male touches female or vice versa they conglobate. To avoid disparity among individuals of the same species, volvating pill-millipedes evolved stridulation behaviour for communication. The male broadcasts appropriate signal to female through stridulation to advertise its interest in mating. The females test the male's fitness by conglobation and suitable male uncoils the partner through stridulation signals. Male with its pygidium successfully uncoils the female and attains suitable orientation for courtship. Male pairs with female ventro-ventro contact in opposite direction to deposit sperm into the vulva of female. The duration of mating varies from species to species and usually a lapse from 3 to 30 min. Vibration generated by stridulation is species-specific and its perception mechanism in pill-millipedes is yet to be clearly understood. Present study emphasized the structure of stridulatory organs, mechanism of stridulation and pattern of mating behaviour in four species of pill-millipedes. [ABSTRACT FROM AUTHOR]

The presence and use of a stridulatory organ (SO) to produce vibrational signals is highly variable and structured within the ants. The file and scraper that make up the SO are specialized morphological features not used for functions other than stridulation (a vibratory signal production mechanism) and not found in non-stridulating species. It has been hypothesized and generally accepted that the stridulatory organ first evolved to alert nest mates of burial and need for rescue. Based on this premise, arboreal species are expected to exhibit a reduction of use of vibrational signals when compared to terrestrial species. Using ancestral state reconstruction, we have mapped the presence of the SO on a molecular phylogeny of the ants and found support for the hypothesis that the SO evolved multiple times in the ants. We quantitatively tested the hypothesis that stridulation evolved initially to signal burial/rescue by comparing the presence of the SO to general foraging and nesting preferences for 76 genera evenly spread throughout the currently accepted ant phylogeny. We found that a greater proportion of genera that are considered primarily arboreal possess a SO, as opposed to the ground nesting genera, and none of the five entirely subterranean genera included in this study possess a SO. We therefore reject the previous hypothesis regarding burial/rescue signaling. [ABSTRACT FROM AUTHOR]

Some insects produce and use sound during multiple behaviors including many aspects of reproduction. Variation in call structure depends on the evolved morphological structures used to produce the sound and encode function. Beetles in the genus Nicrophorus produce stridulation by rubbing plectra, located on the ventral side of the elytra, against a pars stridens, located on the caudal end on the fourth and fifth abdominal segment in females and males, respectively. During field surveys for the endangered N. americanus, survey crews have historically used a small V-shaped notch cut in the caudal end of the right elytron to serves as a permanent marking method. No study, however, has examined the effect of this marking technique on the characters of stridulation or consequences for reproductive behavior and fitness. Here we show that one temporal and one spectral character of sound change significantly following elytron clipping, and that reproductive success is significantly decreased in all breedings in which a parent beetle is elytron-clipped. We recommend replacement of this marking technique with non-invasive methods to ensure conservation of this endangered species. [ABSTRACT FROM AUTHOR]

Vibrational and acoustical signals of Trilophidia annulata (Thunb.) are described for the first time. Oscillogramms are presented. [ABSTRACT FROM AUTHOR]

Mixed courtship vibro-acoustical signals of Conocephalus fuscus (Fabr.) (= discolor Thunb.) and C. dorsalis (Latr.) males have been registered for the first time. Oscillograms are presented. [ABSTRACT FROM AUTHOR]

Vibrations and sounds, collectively called vibroacoustics, play significant roles in intracolony communication in termites, social wasps, ants, and social bees. Modalities of vibroacoustic signal production include stridulation, gross body movements, wing movements, high-frequency muscle contractions without wing movements, and scraping mandibles or tapping body parts on resonant substrates. Vibroacoustic signals are perceived primarily via Johnston's organs in the antennae and subgenual organs in the legs. Substrate vibrations predominate as vibroacoustic modalities, with only honey bees having been shown to be able to hear airborne sound. Vibroacoustic messages include alarm, recruitment, colony activation, larval provisioning cues, and food resource assessment. This review describes the modalities and their behavioral contexts rather than electrophysiological aspects, therefore placing emphasis on the adaptive roles of vibroacoustic communication. Although much vibroacoustics research has been done, numerous opportunities exist for continuations and new directions in vibroacoustics research. [ABSTRACT FROM AUTHOR]

The neural mechanisms underlying cricket singing behavior have been the focus of several studies, but the central pattern generator (CPG) for singing has not been localized conclusively. To test if the abdominal ganglia contribute to the singing motor pattern and to analyze if parts of the singing CPG are located in these ganglia, we systematically truncated the abdominal nerve cord of fictively singing crickets while recording the singing motor pattern from a front-wing nerve. Severing the connectives anywhere between terminal ganglion and abdominal ganglion A3 did not preclude singing, although the motor pattern became more variable and failure-prone as more ganglia were disconnected. Singing terminated immediately and permanently after transecting the connectives between the metathoracic ganglion complex and the first unfused abdominal ganglion A3. The contribution of abdominal ganglia for singing pattern generation was confirmed by intracellular interneuron recordings and current injections. During fictive singing, an ascending interneuron with its soma and dendrite in A3 depolarized rhythmically. It spiked 10 ms before the wing-opener activity and hyperpolarized in phase with the wing-closer activity. Depolarizing current injection elicited rhythmic membrane potential oscillations and spike bursts that elicited additional syllables and reliably reset the ongoing chirp rhythm. Our results disclose that the abdominal ganglion A3 is directly involved in generating the singing motor pattern, whereas the more posterior ganglia seem to provide only stabilizing feedback to the CPG circuit. Localizing the singing CPG in the anterior abdominal neuromeres now allows analyzing its circuitry at the level of identified interneurons in subsequent studies. [ABSTRACT FROM AUTHOR]

The romantic notion of crickets singing on a warm summer’s evening is quickly dispelled when one comes ear to ear with a stridulating male. Remarkably, stridulating male crickets are able to hear sounds from the environment despite generating a 100 db song (Heiligenberg ; Jones and Dambach ). This review summarises recent work examining how they achieve this feat of sensory processing. While the responsiveness of the crickets’ peripheral auditory system (tympanic membrane, tympanic nerve, state of the acoustic spiracle) is maintained during sound production, central auditory neurons are inhibited by a feedforward corollary discharge signal precisely timed to coincide with the auditory neurons’ maximum response to self-generated sound. In this way, the corollary discharge inhibition prevents desensitisation of the crickets’ auditory pathway during sound production. [ABSTRACT FROM AUTHOR]

Stridulation was elicited in tethered gomphocerine grasshoppers of the species Stenobothrus rubicundus in order to identify interneurons of the stridulation pattern generator, and describe their morphological and physiological properties. Nine types of such neurons could be found and characterized; eight of those could additionally be compared to corresponding neuron types previously known from other species. As shown in detail for one selected type, the neurons of the stridulation pattern generator are very similar in their anatomical appearance, and possess similar physiological qualities at least in two species with similar stridulation patterns. Stridulation interneurons of species with largely different stridulatory motor patterns have a similar morphology, but show a different activation timing throughout the stridulation. Nevertheless, special properties such as resetting or initiation capability of certain stridulation interneurons seem to be conserved throughout the species. The results suggest that the stridulation pattern generator of different species consists of a uniform set of interneurons that change their activity pattern to produce species-specific song movements. [ABSTRACT FROM AUTHOR]

Grasshoppers produce a variety of sounds generated by complex movements of the hindlegs. Stridulation, performed in the context of partner finding, mating and rivalry, can be released by pressure injection of cholinergic agonists into the protocerebrum. Particularly stimulation with muscarinic agonists induced long-lasting stridulation that resembled the natural behaviour to an astonishing degree, not only with respect to their temporal structure and right/left coordination, but also to changes in the song sequences according to the progress of courtship stridulation, even including accessory movements of other parts of the body. According to the complexity of their stridulatory behaviour ten gomphocerine species were chosen for this comparative study. The results indicate that the protocerebrum fulfils two important tasks in the control of stridulation: (1) it integrates sensory input relevant to stridulation that represents a certain behavioural situation and internal state of arousal, and (2) it selectively activates and deactivates the thoracic networks that generate the appropriate movement and sound patterns. With the knowledge of the natural behaviour and the accessibility to pharmacological and electrophysiological studies, the cephalic control system for stridulation in grasshoppers appears to be a suitable model for how the brain selects and controls appropriate behaviours for a given situation. [ABSTRACT FROM AUTHOR]

In tethered, minimally dissected grasshoppers stridulation was elicited by DC brain stimulation. Intracellular recording, stimulation and staining of interneurons in the metathoracic ganglion complex were performed simultaneously with measurements of hindleg movements. The functional significance of interneurons for generation of the stridulation rhythm and bilateral coordination of the hindlegs was tested and quantitatively analysed. Interneurons involved in stridulation were found in the metathoracic and abdominal neuromeres. Typically they included arborizations in a dorsal neuropil parallel to the long axis of the ganglion. Interneuron T3-LI-3 started and drove the ipsilateral rhythm generator. The stridulation rhythm was reset by interneuron A1-AC-1. It was stopped if interneuron T3-AC-1 was stimulated. Bilateral coordination of stridulation movements was based on excitatory and inhibitory pathways between the hemiganglionic networks. Switching in the coordination of hindleg movement patterns was induced by changes in the discharge rate of the bilateral arborizing interneuron T3-LC-4. The hemiganglionic interneurons T3-LI-3 and T3-LI-1 influenced coordination via the activity level within the networks. [ABSTRACT FROM AUTHOR]

Stridulation of grasshoppers is controlled by hemisegmental pattern generator subunits which probably are restricted to the metathoracic ganglion complex (TG3-complex). The coordination of left and right pattern generator subunits depends on commissures of the TG3-complex (Ronacher 1989). The coordination of the stridulatory movements was studied in Chorthippus dorsatus males with partial mediosagittal incisions in the TG3-complex. Animals bearing anterior incisions in the TG3-complex, by which all commissures of the metathoracic neuromere and the first abdominal neuromere were transected, were still able to produce bilaterally coordinated species-specific stridulatory movements. Commissures of the T3- and A1-neuromere, thus, are not necessary, and the A2-, A3-commissures are sufficient for this coordination (Figs. 3, 4). Animals with partial posterior incisions, extending until A1, had deficits in their stridulation pattern; the coordination between the hindlegs was impaired though not completely lost (Fig. 6). This is discussed in view of the structure of 'stridulation interneurons' identified in a related grasshopper species ( Omocestus viridulus). These results indicate an unexpected substantial contribution of the abdominal neuromeres A2 and A3 to the control of stridulatory movements. This constitutes an interesting parallel to the flight control system of locusts where interneurons located in the first 3 abdominal neuromeres also appear to contribute to the flight pattern generator (Robertson et al. 1982). [ABSTRACT FROM AUTHOR]

In three grasshopper species the activity of one tympanal nerve and the synaptic activity of the auditory G neuron were recorded under the following conditions: (i) with an acoustic stimulus tested during rest, (ii) during stridulation alone, and (iii) with the acoustic stimulus during stridulation. Response modulations of auditory interneurons such as activation in the stridulatory rhythm, 'switching off' and 'auditory windows' are entirely due to peripheral phenomena. The biophysical effects of stridulation on the tympanal membrane and auditory receptors remain to be analysed. [ABSTRACT FROM AUTHOR]

The forewing of the cricket is activated during the performance of two different behaviours, flight and stridulation. Intracellular recording and staining techniques were employed to determine the neuronal basis for these two behaviours and how they are interrelated. Both motor patterns were studied in a deafferented preparation. Stridulation was elicited by electrical stimulation of the brain and flight by brief puffs onto the cerci. These observations suggest that there are two distinct neural networks which control flight and stridulation. [ABSTRACT FROM AUTHOR]

In gomphocerine grasshoppers the neuromuscular patterns of stridulatory hindleg movements are produced by metathoracic rhythm generators under the control of cephalic command neurons. Injections of cholinergic agonists into the protocerebrum activate this command system which induces the performance of stridulatory sequences, resembling natural species specific movements. Injections of GABA, glycine and picrotoxin into the central protocerebrum of the species Omocestus viridulus, Chorthippus mollis and Ch. biguttulus revealed a contribution of inhibitory mechanisms to the control of the stridulatory behaviour. The experiments suggest that inhibition interferes with the cephalic command systems at three levels: (1) sustained inhibition through picrotoxin sensitive receptors acting on all command units while grasshoppers are at rest, and during stridulation on all command units except the one activating the pattern generators of the currently performed movements; (2) premature termination of song sequences, experimentally induced by injections of GABA and glycine; and (3) coupling of a timing mechanism that terminates a song sequence or its subunits with a particular movement pattern after specific durations. These results together with those from previous studies on the pharmacological activation of stridulatory behaviour suggest that a balance of inhibitory and excitatory inputs to the command system selects the appropriate song type and controls its performance. [ABSTRACT FROM AUTHOR]

During courtship sequences male grasshoppers of the species Omocestus viridulus successively perform with their hindlegs three different stridulatory movement patterns: ordinary stridulation, hindleg shaking and precopulatory movements. Microinjection of acetylcholine into protocerebral neuropil regions can either elicit complete courtship sequences or evoke one of the three motor patterns. Intracellular recordings and stainings revealed three types of descending brain neurons: B-DC-3, B-DC-4 and B-DC-5. All three types of interneurons have a medial axon position in the connectives. They cross the midline of the protocerebrum and exhibit a profuse arborization pattern within the medial dorsal protocerebral neuropil. Stimulation of each type of interneuron specifically elicits one particular motor pattern of courtship behaviour. Courtship of the grasshopper O. viridulus may therefore be controlled by successive activation of these descending brain neurons. [ABSTRACT FROM AUTHOR]

Stridulation in many gomphocerine grasshoppers is characterized by specific phase shifts between the two hindlegs as well as different movement patterns produced by the left and the right leg. The underlying neuronal excitation patterns are generated by networks on either side of the metathoracic ganglion. The role of the intraganglionic commissures in right-left coordination and the production of differing movement patterns was investigated by transecting the metathoracic ganglion mediosagittally in Omocestus viridulus, Chorthippus biguttulus and Chorthippus mollis. In all three species, after this operation both hindlegs produced the same pattern and no longer different movements. The effects of transection on coordination differed: rapid movement rhythms, like those typical of Ch. biguttulus and the vibratory parts of the song of Ch. mollis, on the two sides drifted with respect to one another. In contrast, the slow rhythms characteristic of O. viridulus and the song subunits of Ch. mollis were completely synchronized. It is inferred that in intact animals the pathways for coordination of the rapid stridulatory rhythms are exclusively intraganglionic, whereas the phase relations of the slow rhythms are additionally influenced by way of anterior right-left connections, perhaps within the suboesophageal ganglion. [ABSTRACT FROM AUTHOR]

The coconut rhinoceros beetle Oryctes rhinoceros produces different kinds of stridulatory sound under different conditions. Intense stridulations are made quite frequently by the male during courtship and mating attempts. Males also produce characteristic stridulations during aggressive encounters with other beetles, and distress stridulations, when disturbed manually. Females also stridulate, though less frequently. Sexually immature females produce feeble repellence stridulations while courted by males. Gravid females, when confined with males, are found to mimic the courtship and mating behaviour of the males, meanwhile producing intense stridulations resembling male courtship and mating stridulation. This behaviour, presumably has an ovipository motive and, to our knowledge, is the first instance of ''pseudomale' activity to be reported in insects. Stridulatory mechanism comprises rubbing of a specialised region along the margin of the apex of the elytron -the pars stridens, against a series of striations -the plectrum, occupying the dorsum of the 7th abdominal tergite. Stridulation is possible with a single pars stridens, either of the left or right elytron, both being identical. No sexually dimorphic difference is apparent in the pars stridens. Plectral structure exhibits sexual dimorphism, being much prominent in the male. Wing-locking is necessary to keep the elytra in the stridulatory position. Locking is effected by a longitudinal flange along the median side of one elytron (either the left or right, irrespective of the sex) fitting into a corresponding depression along the other. This differs from the reported cases in other coleopterans in which the flange of the left elytron extends under the right when locked. [ABSTRACT FROM AUTHOR]

Light-based stimuli elicited acoustic responses in male Hylesinus aculeatus Say (Curculionidae: Scolytinae: Hylesinina) instantaneously, with 100% reliability. Stridulations were elicited with a white light beam in a dark environment and recorded with an ultrasonic microphone. Acoustic responses were consistent, and, when compared with sounds produced under stressful conditions (i.e. physical stimulation), no significant differences were found. Hylesinus aculeatus possess an elytro-tergal stridulatory organ and acoustic communication is only present in males. This is also the first report of acoustic communication for this species. Instantaneous light-elicited acoustic communication has potential applications in the development of electronic traps and real-time acoustic detection and identification of beetles, border biosecurity, and noise-reduction in acoustic data collection. [ABSTRACT FROM AUTHOR]