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To support the development of new low cost instrumentation particularly suited for bioacoustic studies, CIBEA is involved in testing instruments, devices and components available on the market. For the development of real-time sound analysis software and of the Digital Signal Processing Workstation used in CIBRA activities, many tests have been made particularly to find sound boards and interfaces (PCI, PCMCG, USB, FireWire) suitable for the specific needs of each research. Many high quality sound acquisition boards are on the market to provide recording quality often better than DAT recorders. Several low-cost AD/DA boards are available for musical application and most of them can be used for sound acquisition. Nevertheless, not all of these equipment has enough acoustic quality or accuracy to be used in high quality recording and sound analysis. The board should be accurately selected to match the needs of the research and the quality level of the whole electroacoustic chain used. Choosing boards with both analogue and digital l/O is recommended.

The poster describes the experimental set-up and outlines the procedure for monitoring the movements of Homarus gammarus inside a marine protected area by means of an acoustic VEMCO VR28T tracking system. It consists of a four channel receiver, connected to a four element hydrophone array, and of pingers, i.e. transmitters which emit an acoustic signal at a fixed period and frequency (in our case 46.2 pulses per minute and 76.8 kHz, respectively) for ten days. The quad hydrophone array provides 360 degrees coverage so that the direction of transmitted signals can be determined both aurally and electronically using TRACK28 software. In this case the bearing to the transmitter is shown graphically on the screen of a connected computer and all data received are saved to a disk file. The pinger was positioned dorsally on the animal. In order to check the hindering effects of the pinger, observations on three marked animals were carried out in a tank from October to December 2000. The 24 h activity of the animals was recorded using a high sensitivity videocamera. A non-marked lobster was present in the same experimental tank and kept under the same conditions. We found no evident difference in the behaviour of both types of animals. In May 2001 one lobster was released inside the Natural Marine Reserve of Miramare and its activity recorded as long as possible. Results of this first tracking are presented here.

Little information exists about how noise exposure may modulate agonistic behaviour of some sonic fish in which perception of sounds produced by conspecifics is crucial in interpreting the message conveyed by the opponents. Recently, it has been demonstrated that temporary hearing impairment can be induced by exposing fish to certain periods of white noise. Experiments were designed to test the hypothesis that elevation of hearing thresholds my means of exposure to noise) of a sonic fish, the croaking gourami Trichopsis vittata, could alter the quality of sound produced because of the altered feedback route in sound perception and production loop. This experiment also tested the hypothesis that altered characteristics of the sound produced would subsequently modulate the outcome of the behavioural contest. Test subjects were exposed to 300 - 4000 Hz white noise (142 dB; re: 1 mPa) for 12 and 24 hours, respectively. The hearing threshold shifts were evaluated at the end of noise exposure as well as one day and five days after exposure with the use of the auditory brainstem response recording protocol. The frequency range tested (600 - 2500 Hz) corresponded to the fish best hearing range as well as to the range of the croaking sounds emitted by the fish. Hearing threshold was found significantly elevated after noise exposure. Recovery, however, appeared faster in 12-hr noise exposed fish than those from the 24-hr exposure group. The croaking sounds produced by noise-exposed fish were also recorded through staged contests. The results were used to compare with the sounds produced prior to the exposure. Details of differences in sound spectra as well as changes of agonistic behaviour are presented and discussed (supported by National Organization for Hearing Research, NIMH-58198, Institute of Museum and Library Service-LL90187).

Vocalisation has been recognised as one of the important modes of animal communication. In one anabantoid fish, the croaking gourami Trichopsis vittata, both sexes produce loud, croaking sounds during agonistic encounters and courtship. It is known that sound emission of this fish is mostly involved with the ritualised portion of the contest, which is likely to convey information between the opponents about their respective strength and status. The sound is produced by a complex mechanism that involves two modified tendons, located behind each pectoral fin. Due to the external position of these soft structures, parasites, sickness, or injury from fights can easily damage the tendons, leading to muteness. Reduction or even loss of the croaking ability may result in a substantial decreasing of the overall fitness. Experiments were designed to test whether or not croaking gouramis can repair damaged tendons and regain fully functional sound producing organs, as well as to evaluate the effect of muting and recovery on the outcomes of agonistic interactions. Fishes were muted by surgically cutting one or both the tendons that connect the "sonic'' muscle with the fin rays. The occurrence and timing of recovery was evaluated for 30 specimens of T. vittata after surgical muting. Croaking sounds produced by the fish were recorded during staged contests after recovery. Sound from each specimen was previously recorded before and after muting as well, for comparison. The elapsed time of reconnection of each tendon to the relative fin ray was also recorded. Some fishes were found to recover completely within less than 30 days, while others needed up to three months. However, evidence for the beginning of the recovery process was noticed as early as 4 days after operation. Behavioural performance after recovery was normal. Details of sounds produced and changes of behavioural repertoires are discussed (supported by National Organization for Hearing Research, NIMH-58198, Institute of Museum and Library Service-LL90187).

Humpback whale males produce complex sounds with a hierarchical organisation of 'units' 'phrases', 'themes', and 'songs' (Payne and McVay 1971). On 9 November 2000 the vocalisations of one humpback whale were recorded at Arraial do Cabo (23° 03' S; 42° 02' W), a migratory corridor of baleen whales. The recordings were obtained using a fixed hydrophone (CN 60; 40 m deep) and a Tascam DA-60 MK 11 digital tape recorder. The recordings were analysed with Cool Edit Pro 1.2 (6,000 Hz; 32-bit; mono; 512-pt Hamming windowed time slices with 100% overlap). 19 themes were identified from a song sample of 1h 27min. The units were classified in 3 categories: harmonic, modulated amplitude and impulsive sounds (Maeda et al. 2000). For 22min 66s, there was no repetitions of themes, forming a song cycle of 12 themes. In the remainder of the song, there was a mixture of unprecedented themes with some of the 12 initial themes. The theme 7 repeated three times, theme 5 twice and themes 9, 10, and 11 once each. Theme 7 showed a variation in the repetition rate of its phrase. On the first occurrence, the phrase repeated twice. On the second time, it repeated 12 times. On the third time, it repeated 11, and in the last, 5 times. Theme 5 only had a variation between 10 and 11 repetitions. The impulsive sounds themes 10 and 11 had no phrases. Theme 9 had its phrase repeated 8 and 3 times. Themes 6, 9, 13, and 17 had 8 units; they were the most diverse themes. Razafindrakoto (2001) observed a frequency shift in humpback whale songs when peak frequency was lower than the ambient noise. The singer could shift the frequency to avoid the ambient noise (Maeda et al. 2000). We also found this frequency shift (support: CAPES, CASOP - Brazilian Navy, Redley, Cetacean Society International and Whale and Dolphin Project).

Little is known about female humpback whales' vocal emissions. On 28 July 2000 a humpback whale mother and its offspring was followed by means of a Zodiac boat for 1h close to the coast of Pontal de Atalaia (23° 03'S; 42° 02'W), a migratory corridor of the species. During the observation, 18min 36s of the female vocalisations' recordings (Sony WM-D3) were obtained using a hydrophone (Celesco LC-10; 3 m deep). The recordings were analysed with Cool Edit Pro 1.2 (44,100 Hz, 32-bit, mono). The emissions did not vary, showing only rising frequency units. The 'song' was formed from 47 'units'. The maximum frequency of background noise was 2 kHz. The units duration varied between 0.71 to 1.03 s (mean = 0.97 + 0.10 s; N = 27), the initial frequency varying from 5.0 to 5.3 kHz (mean = 4.9 + 1.0 kHz), final frequency from 5.4 to 5.7 kHz (mean = 5.4 + 1.0 kHz), and the peak with the most amplitude was -14.37 dB. Most of the units (59%) had a duration between 0.96 to 0.97 s. The interval between units had a duration between 21.49 and 21.58 s, except one unit with 14.44 s. All the vocalisations were followed by echo during ca. 10 s coming from the rocky coast. Frazer & Mercado III (1999) concluded that humpback whale song is a long-range sonar used by male humpbacks to locate other whales on the breeding ground. The echo presence in the female vocalisations and her closeness to the coast makes us believe that the reason for these emissions was echolocation. Furthermore, there was a practically constant interval duration between emissions, low frequency modulation and little variation of emissions. This conclusion is reinforced by the fact that during an 1h observation, the female kept the coast at port and its offspring at starboard, constantly emitting sounds (support: CAPES, Redley, Cetacean Society International and Whale and Dolphin Project).

We auditory evoked response (AER) technique an electrophysiological far-field recording method widely used in evaluating vertebrate hearing, was adopted to butterflies to overcome limitations of behavioural and invasive electrophysiological techniques. Response to tone bursts of different frequencies (250 Hz - 15 kHz) and amplitudes was recorded from the surface of the thorax of Erebia pronoe, E. aethiops and E. medusa (Lepidoptera: Satmidae). AER-waveforms of all three species consisted of 2-3 positive peaks. The polarity of these traces was not affected when switching the phase of the sound stimulus by 180°. Latencies of AERS increased with decreasing sound pressure level and frequencies. Perforation of the tympana at the base of the forewings totally eliminated AERS at all frequencies, demonstrating that the recorded potentials were generated solely within the auditory pathway in response to acoustical stimuli. Decapitation did not reduce the number of peaks and amplitude of AER traces, indicating that auditory evoked potentials are generated entirely within the thorax. AER audiograms revealed best auditory sensitivity between 2 and 4 kHz in E. pronoe and E. aethiops, with lowest thresholds at 36 and 31 dB SPL, respectively. These data demonstrate that the AER recording technique is a useful method for measuring hearing in insects when rapid measurements of a large number of species or when repeated testing of animals are required (e.g. during ontogenetic studies). This research was supported by the Austrian Science Fund (FWF grant No 12411 to F.L.) and by the Slovenian Science Foundation (SZF-fellowship to D.R.).

The male calling song of Poecilimon fussi, an Eastern European bush-cricket species, is described for the first time and fully illustrated by oscillograms at several speeds. The calling songs of 18 males (9 from Transylvania [Rumania] and 9 from Hungary) have been analysed. The male calling song of P. fussi is a long syllable-sequence in which syllables follow each other in quick succession. During the whole song two types of syllable can be observed. Type "A'' is a single pulse-series lasting for 150-200 ms at 22-23 °C, composed of 40-50 pulses without any additional, isolated pulse at its end. In type "B'' a main pulse series of 100-150 ms duration (22-23 °C), containing 60-70 pulses is followed by a single (or a few) additional pulsels). In the course of the whole song a cyclic alternation of two phases can be observed. Phase 1 is composed solely of "A'' type syllables while phase 2 is constituted exclusively by "B'' type syllables. The transition between the consecutive phases is quite sudden: there are only a few syllables showing transitional characteristics. While the pulse repetition patterns of "A'' and "B'' type syllables are not unusual in this genus, this kind of two-phased song is unique amongst the Poecilimon species in which the songs have been described.

Species of the genus Endecous are found in tropical and sub-tropical forests of the neotropical region. Most of the studies of the species in this genus are limited to short descriptions based on external morphological characters. At present, eleven species of Endecous have been described, five of them collected in Brazilian territory. Four of them are considered here: E. itatibensis, E. cavernicolus, E. abbreviatus, E. betariensis and also a new species from a cave close to Goianésia town, Goiás State. We describe here the acoustic repertoire in the genus Endecous and we apply these results to solve related taxonomic problems. The species here analysed emit six different acoustic structures with distinct biological functions, related to mating (song for female calling, female recognition, courtship, copulation) and to hierarchical and aggressive behaviour. The main differences between species are in the number of notes in the calling song chirps, which is the most species-specific character. The results we obtained through this acoustic analysis suggest that itatibensis and abbreviatus are the same species.

Seismic signals occur in at least two distinct lineages of subterranean rodents (Bathyergidae and Spalacinae), indicating that this mode of communication cannot be explained solely in terms of phylogenetic history. Understanding the evolutionary context in which each signal type has developed remains a significant challenge to biologists studying communication in subterranean rodents. The importance of social behaviour for the type of vibrational signals used has been emphasised, implying that solitary taxa are more likely to exhibit seismic signals than social taxa because of their greater need for communication between burrows. Because seismic signals propagate better through the soil than vocal signals, the former should be favoured in solitary species in which communication occurs primarily between burrows. The majority of Ctenomys species are solitary and territorial, living in individual burrows that never approach other burrows nearer than 40 cm outside of the reproductive season, thus long distance inter-burrow communication is a candidate for the use of seismic signals. Nevertheless, no Ctenomys is known to produce seismic signals but almost all of them vocalise loud enough to be heard at a considerable distance outside the burrows. Data from six Ctenomys species show that these vocalisations are low frequency, repetitive, rhythmic signals which present structural similarities with the seismic signals emitted by other subterranean rodents. These facts suggest that the use of low-frequency rhythmic signals could be a result of the constraints imposed by the underground environment and that the propagation conditions may determine that rhythm is more reliable than frequency modulation. Then, solitary subterranean rodents may use low frequency, rhythmic, repetitive signals for long distance communication, either vocal or seismic, to overcome the environmental constraints. A possible explanation for the use of one of both channels by different species has been discussed elsewhere.