Spawning sounds in meagre Argyrosomus regius recorded in the Gironde estuary, France

During their spawning period (June to mid-July) in the Gironde estuary, meagre Argyrosomus regius produce two distinct sounds: regular long grunts, the most common calls, and sometimes also short grunts. It is suggested that long grunts serve the formation of spawning aggregations and short grunts announce the beginning of courtship behaviour. The meagre's long grunts include long series of 30–112 closely spaced pulses placed into call units. Each pulse produces multiple and rapidly decaying swimbladder vibrations with a dominant frequency varying between 336 and 444 Hz.     

Sound production during competitive feeding in the grey gurnard

The acoustic repertoire of captive grey gurnard Eutrigla gurnardus during competitive feeding consisted of three types of sound: knocks, grunts and growls. Knocks were audible as a single sound, whereas grunts and growls were perceived as longer, pulsed sounds to the human ear. Typically, knocks were composed of 1–2 pulses, grunts of 4–8 pulses and growls >10 pulses. Growls were longer and had shorter pulse periods than grunts. All sound types had peak frequencies of c . 500 Hz. The sequences of behaviours observed during feeding interactions suggest that grey gurnard obtain food both by scramble and contest tactics. Competing fish emitted knocks mainly while grasping a food item and also during other non‐agonistic behaviour, suggesting that knock production may reflect a state of feeding arousal but could also serve as a warning of the forager's presence to nearby competitors. Grunts were mainly emitted during frontal displays, which were the most frequent behavioural act preceding grasps, suggesting that they may play a role in deterring other fish from gaining access to disputed food items.     

Sound Production in Codoma ornata (Girard) (Cyprinidae)

Male Codoma ornata produce sounds associated with aggression and spawning activities during the breeding season. Females do not produce sounds. Males most often produced sounds associated with escalated displays of aggression, courtship and the spawning act. C. ornata spawn in crevices, but previously were reported to spawn as egg-clusterers in cavities. Structurally, sounds are low frequency, vary in duration according to context and are not harmonic. The mechanism of sound production is unknown.     

Sound production and associated behavior in a cichlid fish,Cichlasoma centrarchus. II. Breeding pairs

Synopsis Pairs of Cichlasoma centrarchus were observed daily in the laboratory. Both males and females made sounds during a breeding cycle but all sounds were aggressive in context; no sounds were heard to accompany courtship. Males made more sounds before spawning than afterwards and these were associated with territorial defense and with establishment of dominance over the female. Females produced more sounds after spawning than before, most in the context of brood defense but some toward the male during pre-spawning nest preparation. Prior to spawning, the number of sounds made by the males toward their mates increased but the aggressive actions accompanying them became less intense. No such inverse correlation of agonistic intensity with number of sounds made was found for the females. From this study and earlier ones by the author it was concluded that sound in this species is a threat display which 1) provides an expression for agonism alternative to the performance of actions which could injure the female or drive her away, and 2) lessens the risk of injury to male or female during territory or brood defense.     

Sound production during courtship and spawning of Oreochromis mossambicus: male–female and male–male interactions

The role of sound production of the Mozambique tilapia Oreochromis mossambicus in agonistic and mating interactions observed during hierarchy formation and in established groups was examined. Only territorial males produced sounds, during male–female and male–male courtship interactions and during pit-related activities ( e.g. dig, hover and still in the nest). Sound production rate was positively correlated with courting rate. Although sounds in other cichlids are typically emitted in early stages of courtship, O. mossambicus produced sounds in all phases, but especially during late stages of courtship, including spawning. It is suggested that the acoustic emissions in this species may play a role in advertising the presence and spawning readiness of males and in synchronizing gamete release.     

On the electromotor neurons of both electric organs of Pollimyrus isidori (Mormyridae, Teleostei)

The electromotor neurons (EMNs) of the adult electric organ of Pollimyrus isidori and the "giant neurons" (GNs) found in the more rostral part of the spinal cord were investigated both with light and electron microscopical methods. The two kinds of neuron are more or less similar in size, about 30 microns, and are found in the more dorsal part of the spinal cord. The EMNs show somatosomatic gap junctions, as do the GNs. In addition, chemical synapses could be found between nerve fibres and both types of neurons. Histochemical investigations show that the EMNs and the GNs are both AChE positive. On the basis of the arguments presented in the discussion, we believe that the "giant neurons" are the electromotor neurons of the larval electric organ of Pollimyrus isidori.     

Saccular potentials of the vocal plainfin midshipman fish, <Emphasis Type="Italic">Porichthys notatus</Emphasis>

The plainfin midshipman fish, Porichthys notatus, is a vocal species of teleost fish that generates acoustic signals for intraspecific communication during social and reproductive behaviors. All adult morphs (females and males) produce single short duration grunts important for agonistic encounters, but only nesting males produce trains of grunts and growls in agonistic contexts and long duration multiharmonic advertisement calls to attract gravid females for spawning. The midshipman fish uses the saccule as the main acoustic endorgan for hearing to detect and locate vocalizing conspecifics. Here, I examined the response properties of evoked potentials from the midshipman saccule to determine the frequency response and auditory threshold sensitivity of saccular hair cells to behaviorally-relevant single tone stimuli. Saccular potentials were recorded from the rostral, medial and caudal regions of the saccule while sound was presented by an underwater speaker. Saccular potentials of the midshipman, like other teleosts, were evoked greatest at a frequency that was twice the stimulus frequency. Results indicate that midshipman saccular hair cells of non-reproductive adults had a peak frequency sensitivity that ranged from 75 (lowest frequency tested) to 145 Hz and were best suited to detect the low frequency components (≤105 Hz) of midshipman vocalizations.     

The significance of sound interception to males of the bicolor damselfish,Pomacentrus partitus,during courtship

Synopsis Playback experiments conducted in the field and the laboratory demonstrated the use of sound interception in bicolor damselfish,Pomacentrus partitus. Two courtship sounds produced by male bicolors: the ‘chirp’ which occurs at the initiation of courting and the ‘grunt’ which occurs near the termination, just prior to spawning, were found to hold different meanings to intercepting male competitors. Males responded to grunt playback with directional swimming towards the sound source and increased courtship behavior. No directional response was observed during chirp playback. The grunt sound appears to indicate that a spawn-ready female is present near the sound source. Males therefore move towards it, likely to interfere with the imminent spawning or to gain a possible spawning partner. Such is not observed in response to chirps, as little advantage would be gained by moving to the source of a sound which is known to serve as an ‘advertisement’ or ‘territorial keep-out’ signal. Thus, upon intercepting a neighbor's chirps, males exhibit courting within their own territory, or directly court a nearby female.     

Behaviours Associated with Acoustic Communication in Nile Tilapia (Oreochromis niloticus)

Background

Sound production is widespread among fishes and accompanies many social interactions. The literature reports twenty-nine cichlid species known to produce sounds during aggressive and courtship displays, but the precise range in behavioural contexts is unclear. This study aims to describe the various Oreochromis niloticus behaviours that are associated with sound production in order to delimit the role of sound during different activities, including agonistic behaviours, pit activities, and reproduction and parental care by males and females of the species.

Methodology/Principal Findings

Sounds mostly occur during the day. The sounds recorded during this study accompany previously known behaviours, and no particular behaviour is systematically associated with sound production. Males and females make sounds during territorial defence but not during courtship and mating. Sounds support visual behaviours but are not used alone. During agonistic interactions, a calling Oreochromis niloticus does not bite after producing sounds, and more sounds are produced in defence of territory than for dominating individuals. Females produce sounds to defend eggs but not larvae.

Conclusion/Significance

Sounds are produced to reinforce visual behaviours. Moreover, comparisons with O. mossambicus indicate two sister species can differ in their use of sound, their acoustic characteristics, and the function of sound production. These findings support the role of sounds in differentiating species and promoting speciation. They also make clear that the association of sounds with specific life-cycle roles cannot be generalized to the entire taxa.     

Courtship and spawning sounds in bird wrasse Gomphosus varius and saddle wrasse Thalassoma duperrey

Acoustic signals from the bird wrasse Gomphosus varius and saddle wrasse Thalassoma duperrey were recorded on coral reefs in Hawaii. Terminal phase males in both species emit two types of pulse trains (type I and type II). Type I pulses were produced during spawning and courtship, while type II pulses were associated only with courtship behaviours. Gomphosus varius type I pulses were of lower frequency than T. duperrey type I pulses (271 v. 840 Hz) and were of narrower band. Discriminant function analyses revealed interspecific differences between type I pulse trains and individual pulses of both types. This study is the first documentation of courtship and spawning sounds in sympatric labrids and shows divergence in acoustic signals.     

The role of acoustic cues in the breeding repertoire of the brook stickleback

Sticklebacks are used as a model system in behavioral and evolutionary research, and therefore it is important to have a complete understanding of their biology. Despite this, the presence of acoustic signals has never been explored. This study examines acoustic cues in brook sticklebacks during courtship, spawning, egg guarding, and fry guarding. Although some fish produce sounds during spine flaring, results of this experiment showed that brook sticklebacks do not. Females did produce incidental sounds while depositing eggs in the nest. However, these were low intensity and seem unlikely to be heard over background noise.     

Court and spark: electric signals in the courtship and mating of gymnotoid fish

By mimicking tropical rainy season conditions in aquaria, we stimulated two species of gymnotoid electric fish, Eigenmannia virescens and Apteronotus leptorhynchus, to spawn in captivity. Their courtship activity, breeding behaviour and electric social communication were monitored in several groups over 2 years. Groups of both species established dominance hierarchies correlated with electric organ discharge frequency, aggressiveness and size. Spawning was preceded by several nights of courtship during which the male modulated its electric organ discharge to produce ‘chirps’. Continual bouts of chirping lasted for hours on evenings prior to spawning. These electrical signals play a significant role in courtship and spawning, as gravid E. virescens females could be stimulated to spawn by playing back into the tank a tape recording of male courtship chirps. In both species the chirp invovves a slight increase in frequency followed by a cessation of the dominant frequency. This suggests a common mode of signal production in these two different genera of fish. Chirps are short and abrupt during aggressive encounters, but assume a softer and more raspy quality during courtship.     

The reproductive behavior of <Emphasis Type="Italic">Economidichthys pygmaeus</Emphasis>: secondary loss of sound production within the sand goby group?

In this study, the reproductive behavior of Economidichthys pygmaeus was investigated under laboratory conditions with simultaneous video and acoustic recordings. Males of the freshwater goby E. pygmaeus do not produce sounds either during the courtship/spawning phase or during aggressive interactions. A detailed analysis of the behavioral sequences revealed the absence of any digging and nest-building activities, whereas the other behavioral components of courtship and spawning are similar to those described for other goby species, showing also a similar function. Results were discussed in terms of secondary loss of sound production within the sand gobies, a group of highly soniferous fishes in the family Gobiidae.     

Electric organ discharge variability of Mormyridae (Teleostei: Osteoglossomorpha) in the Upper Volta system

The electric organ discharges (EODs) of five mormyrid species ( Marcusenius senegalensis , Brevimyrus niger , Petrocephalus bovei , Pollimyrus isidori , Hippopotamyrus pictus ) from different sampling sites from the Upper Volta system in West Africa were investigated. EOD waveforms were recorded at high sampling rates in order to compare signal waveform parameters of the different species from different locations. Except for H. pictus , EODs within a species differed significantly from one another in some parameters and waveform variability at least between some sampling sites. In addition, each species showed a continuous spectrum of waveform variations, all or only parts of which were found at certain localities. Although there was variability and sometimes similarities between species, the EOD waveforms were species specific. Knowing their variation spectrum, they can be used for species determination and are probably used for species recognition by the mormyrids. Similarities or differences in EOD waveform expression within a species were not related to geographical distance. By contrast, we suggest that biotic environmental factors at a given location influence the expression of EOD waveforms. These factors affect absolute measurements such as EOD duration and fast Fourier transformation peak frequency as well as the amount of variation for certain waveform parameters across species in a similar manner for a given site. Although EOD waveform might be important for the establishment of reproductive barriers between species, our results suggest that differences in waveforms may not necessarily reflect different species or speciation processes in progress.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 61–80.     

Sound Production by Adult Haddock, Melanogrammus Aeglefinus, in Isolation, Pairs and Trios

Haddock, Melanogrammus aeglefinus, have been previously shown to produce sounds during mating. Several behavioural aspects of sound production of courting haddock were further investigated in relation to sex ratio. We assessed whether (i) single males or females generate sounds when isolated, (ii) sound is produced when one male is present with a female, (iii) sound production becomes altered with the introduction of an additional male, and (iv) sounds are produced independent of egg release. Data were collected from 30 March to 11 June 1999, during the spawning period using small outdoor tanks. Sounds generated by captive males during spawning were categorized as knocks, hums and an intermediate between these two types. Solitary males and females did not produce sounds. Sounds were produced when one male was present with a single female. The knocking call duration increased when a second male was introduced. Sounds produced by males occurred independent of the day of egg release.     

Feature-detecting auditory neurons in the brain of a sound-producing fish

The mormyrid fish Pollimyrus adspersus has auditory specializations for sound pressure detection and uses acoustic displays in its natural social behavior. In this paper it is shown that auditory neurons in the mesencephalon (torus semicircularis) are activated selectively by temporal features of complex sounds. Single neurons were recorded while presenting sounds to fish underwater. The stimuli were acoustic click trains, 400 ms in duration, and were synthesized with differing inter-click-intervals (ICIs). The natural sounds of this species are composed similarly and the range of ICIs synthesized overlapped with the natural range (5–40 ms). One-third of the neurons studied were strongly selective for a narrow range of ICIs, increasing spike rate by ten fold or more at the best ICI compared to the minimum response observed. The best ICI for interval selective neurons remained stable when the sound pressure of the stimulus was changed. Neurons that were selective gave phasic responses to tone bursts, and most had non-monotonic rate level functions. The origin of interval selectivity is discussed and a time-based computational mechanism is proposed. Accepted: 20 December 1996     

Aspects of Species Recognition by Sound in Four Species of Damselfishes,Genus Eupomacentrus (Pisces: Pomacentridae)

Members of four sympatric species of Eupomacentrus carry out reproductive activities at the same time of the year and produce similar pulsed courtship sounds. Such sounds are known to facilitate courtship among conspecifics. Consequently, members of the four species in the field and in the laboratory were tested with the various sounds to determine if they could distinguish their own species sounds from those produced by congeners. The differential responses clearly demonstrate species specific recognition by sound and indicate that the pulse interval and the number of pulses per sound are the important parameters for this recognition.     

Spawning behavior and haremic mating system in the corallivorous butterflyfish,Chaetodon trifascialis, at Kuroshima Island, Okinawa

Territorial and spawning behavior ofChaetodon trifascialis were investigated on a small patch of reef at Kuroshima Island, Okinawa, Japan. Three males and 8 females inhabited the reef, each individual defending a territory against conspecifics of the same sex. Each male territory included 2 or 3 female territories. In the daytime, each male frequently visited the females living in its territory. At dusk in the full or new moon periods, courtship began within the female territories, pair spawning subsequently occurring within or near those territories. When a male actively courted a female in the territory of a second male, the latter male immediately chased off the intruder. Thus, mating occurred only between a male and females living in former's territory. This is the first report of a haremic mating system among butterflyfishes (Chaetodontidae).