Browsing by Author "Fonseca, Paulo Jorge"
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- Acoustic communication in the Lusitanian toadfish, Halobatrachus didactylus: Evidence for an unusual large vocal repertoirePublication . Amorim, Maria Clara Pessoa; Simões, José Miguel; Fonseca, Paulo JorgeThe Lusitanian toadfish Halobatrachus didactylus (Bloch & Schneider) (Batrachoididae) is a well-known sound producer that has an unusual large acoustic repertoire for fish. This repertoire consists so far of five distinct sound categories: boatwhistles, grunt trains, croaks, double croaks and a mixed grunt–croak call. Sixteen males that spontaneously occupied artificial concrete nests placed in the intertidal zone of the Tagus estuary (Portugal) were recorded over 8 days in June/July 2006. During the analysis of the recordings new sound emissions were found. Long grunt trains that sounded to the human ear like a running engine were heard. These sounds differ from the normal grunt trains by having a lower amplitude, a much longer duration (tens of seconds versus ,1 second) and more grunts per call. Other new sound emissions (e.g. triple croaks) were also registered but were heard less frequently. The incidence of the various sound types is given.
- African cichlid Pseudotropheus spp. males moan to females during foreplayPublication . Simões, José Miguel; Fonseca, Paulo Jorge; Turner, George F.; Amorim, Maria Clara PessoaThis study describes a new courtship sound (moan) produced by Pseudotropheus spp. males, not previously reported for cichlids. Moans are short tonal sounds often showing frequency modulation. This sound type is of very low amplitude and is produced when males swim in close proximity to a female, usually before performing more exuberant behavioural exhibitions, such as darting, quivering the body and growling.
- Agonistic sounds signal male quality in the Lusitanian toadfishPublication . Amorim, Maria Clara Pessoa; Conti, Carlotta; Modesto, Teresa; Gonçalves, Amparo; Fonseca, Paulo JorgeAcoustic communication during agonistic behaviour is widespread in fishes. Yet, compared to other taxa, little is known on the information content of fish agonistic calls and their effect on territorial defence. Lusitanian toadfish males (Halobatrachus didactylus) are highly territorial during the breeding season and use sounds (boatwhistles, BW) to defend nests from intruders. BW present most energy in either the fundamental frequency, set by the contraction rate of the sonic muscles attached to the swimbladder, or in the harmonics, which are multiples of the fundamental frequency. Here we investigated if temporal and spectral features of BW produced during territorial defence reflect aspects of male quality that may be important in resolving disputes. We found that higher mean pulse period (i.e. lower fundamental frequency) reflected higher levels of 11-ketotestosterone (11KT), the main teleost androgen which, in turn, was significantly related with male condition (relative body mass and glycogen content). BW dominant harmonic mean and variability decreased with sonic muscle lipid content. We found no association between BW duration and male quality. Taken together, these results suggest that the spectral content of fish agonistic sounds may signal male features that are key in fight outcome.
- Alloparental behavior in the highly vocal Lusitanian toadfishPublication . Ramos, Andreia; Fonseca, Paulo Jorge; Modesto, Teresa; Almada, Vítor Carvalho; Amorim, Maria Clara PessoaIn many fish species in which males guard nests with their eggs, parental care directed to genetically unrelated offspring may arise for example from nest takeovers or cuckoldry. Lusitanian toadfish (Halobatrachus didactylus) has exclusive male parental care and face intensive nest competition during the breeding season that may lead to care of foster eggs. Males of this species use visual displays and sounds when defending their nests frequently resulting in expulsion of the intruder without escalated confrontation. In this study we intended to investigate the existence of alloparental care in Lusitanian toadfish, a behavior whose adaptive significance is still poorly understood. Fish were randomly assigned to three different treatments: parental males in nests with their eggs, parental males with foster eggs and parental males without eggs. Nests with eggs with no nest holder or with females were used as controls. We performed three territorial intrusions over periods of 15 days and observed the acoustic and visual behaviors of residents and intruders. Egg survival was tallied from nests' photographs in all groups. Circulating steroid levels were measured in the three test groups and in another set of non-manipulated males. There were no differences in acoustic and visual territorial defense behaviors among treatments. Egg survival was similar between males (parental and alloparental) and significantly higher than in nests with no nest-tender. Females presented intermediate egg survival. All groups presented similar levels of testosterone and alloparental males showed higher 11-ketotestosterone levels but within the range of levels observed in non-manipulated males. Cortisol levels were similar in all male groups suggesting that experiments did not increase fish stress. The present results suggest the existence of alloparental care in this species.
- Assessing acoustic communication active space in the Lusitanian toadfishPublication . Alves, Daniel; Amorim, Maria Clara Pessoa; Fonseca, Paulo JorgeThe active space of a signal is an important concept in acoustic communication as it has implications for the function and evolution of acoustic signals. However, it remains mostly unknown for fish as it has been measured in only a restricted number of species. We combined physiological and sound propagation approaches to estimate the communication range of the Lusitanian toadfish’s (Halobatrachus didactylus) advertisement sound, the boatwhistle (BW). We recorded BWs at different distances from vocalizing fish in a natural nesting site at ca. 2–3 m depth. We measured the representation of these increasingly attenuated BWs in the auditory pathway through the auditory evoked potential (AEP) technique. These measurements point to a communication range of between 6 and 13 m, depending on the spectral characteristics of the BW. A similar communication range (ca. 8 m) was derived from comparing sound attenuation at selected frequencies with auditory sensitivity. This is one of the few studies to combine auditory measurements with sound propagation to estimate the active space of acoustic signals in fish. We emphasize the need in future studies for estimates of active space to take informational masking into account.
- Call recognition and individual identification of fish vocalizations based on automatic speech recognition: An example with the Lusitanian toadfishPublication . Vieira, Manuel; Fonseca, Paulo Jorge; Amorim, Maria Clara Pessoa; Teixeira, Carlos J. C.The study of acoustic communication in animals often requires not only the recognition of species specific acoustic signals but also the identification of individual subjects, all in a complex acoustic background. Moreover, when very long recordings are to be analyzed, automatic recognition and identification processes are invaluable tools to extract the relevant biological information. A pattern recognition methodology based on hidden Markov models is presented inspired by successful results obtained in the most widely known and complex acoustical communication signal: human speech. This methodology was applied here for the first time to the detection and recognition of fish acoustic signals, specifically in a stream of round-the-clock recordings of Lusitanian toadfish (Halobatrachus didactylus) in their natural estuarine habitat. The results show that this methodology is able not only to detect the mating sounds (boatwhistles) but also to identify individual male toadfish, reaching an identification rate of ca. 95%. Moreover this method also proved to be a powerful tool to assess signal durations in large data sets. However, the system failed in recognizing other sound types.
- Computer-manipulated stimuli as a research tool in Mozambique tilapia Oreochromis mossambicusPublication . Wackermannova, Marie Anna; Horky, Pavel; Amorim, Maria Clara Pessoa; Fonseca, Paulo JorgeMultimodal communication is essential in social interactions in cichlid fish, including conspecifics’ recognition, agonistic interactions and courtship behaviour. Computer-manipulated image stimuli and sound playback offer powerful tools to assess the relative relevance of visual and acoustic stimuli in fish behavioural studies, but these techniques require validation for each taxon. The aim of the present study was to investigate whether Mozambique tilapia Oreochromis mossambicus responds to computermanipulated visual stimuli and acoustic playback. Six experiments were conducted: computer animation playback, video playback, interaction with a mirror, presentation of a live male in a jar alone and combined with courting sound playback or with white noise playback. Individual agonistic interactions (lateral displays, up and down swimming, butting) and courting behaviours (tilting leading, digging) were tallied for each experiment. Our results suggest that non-interactive computer-manipulated visual stimuli is not a suitable tool in behavioural research with Mozambique tilapia. In contrast, interaction with a live male in a jar seems to remain the best visual research instrument inducing significant strong behavioural responses. Although none or only a few agonistic interactions were observed towards video playbacks or computer animations, such interactions significantly increased towards a male in jar and were modulated by courtship sound playback, suggesting the additional relevance of sound playback as a tool in behavioural research with Mozambique tilapia, including the study of multimodal signalling.
- Courtship and agonistic sounds by the cichlid fish Pseudotropheus zebraPublication . Simões, José Miguel; Duarte, Inês G.; Fonseca, Paulo Jorge; Turner, George F.; Amorim, Maria Clara PessoaCourtship and agonistic interactions in an African cichlid species present a richer diversity of acoustic stimuli than previously reported. Male cichlids, including those from the genus Pseudotropheus (P.), produce low frequency short pulsed sounds during courtship. Sounds emitted by P. zebra males in the early stages of courtship during quiver were found to be significantly longer and with a higher number of pulses than sounds produced in later stages. During agonistic intrasexual quiver displays, males produced significantly longer sounds with more pulses than females. Also, male sounds had a shorter duration and pulse period in courtship than in male–male interactions. Taken together, these results show that the acoustic repertoire of this species is larger than what was previously known and emphasize the importance of further research exploiting the role of acoustic stimuli in intra- and interspecific communication in African cichlids.
- Development and characterization of novel microsatellite loci for Lusitanian toadfish, Halobatrachus didactylusPublication . Santos, Carla Sousa; Fonseca, Paulo Jorge; Amorim, Maria Clara PessoaThe Lusitanian toadfish Halobatrachus didactylus is an eastern Atlantic polygynous species showing male paternal care. In this paper we describe 5 novel microsatellite loci obtained by 454 GS-FLX Titanium pyrosequencing of a microsatellite-enriched library. The number of alleles per polymorphic locus varied between 2 and 4, and the observed heterozygosity ranged from 0.082 to 0.600. No significant deviation from Hardy–Weinberg equilibrium was found and there was no evidence for linkage disequilibrium. These markers will be of great value for paternity studies and population genetics of this species.
- Effects of temperature on sound production in the painted goby Pomatoschistus pictusPublication . Vicente, Joana R.; Fonseca, Paulo Jorge; Amorim, Maria Clara PessoaThe painted goby Pomatoschistus pictus emits courtship sounds (drums) that are important in reproductive outcome. The effect of temperature (14–22 °C) on courtship drum features was characterised. Pulse period (or rate) was linearly related with temperature (R2 = 0.83) presenting a Q10 of 2.13. Pulse period decreased by 1.95 ms per 1 °C and varied from 34 ms to 18.6 ms within the studied temperature range. Sound duration changed concomitantly from 1128 ms to 658 ms. Changes in sound duration were due to pulse period rather than pulse number, since the latter was not affected by temperature. Pulse duration was similarly affected by temperature, decreasing by 0.3 ms per 1 °C (R2 = 0.51, Q10 = 1.45) and changing from 10.0 ms at 14 °C to 7.5 ms at 22 °C. Drum emission rate, sound amplitude, fatigue and dominant frequency were also not related to temperature. The temperature effect on pulse rate likely reflects temperature-dependence of the vocal central pattern generator as observed in other animals. In contrast, shorter pulse durations likely result from temperature effects at the peripheral level of the vocal system, as muscle twitches typically shorten with rising temperatures. Because pulse rate is likely important in mate choice and conspecific recognition in fish, including P. pictus, future studies are needed to understand if temperature-related changes in pulse rate are coupled with changes in mate preference as found in insects and anurans.
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