Browsing by Author "Vicente, Joana R."
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- 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.
- Optical micro-tomography “OPenT” allows the study of large toadfish Halobatrachus didactylus embryos and larvaePublication . Felix, Pedro M.; Gonçalves, Ania; Vicente, Joana R.; Fonseca, Paulo Jorge; Amorim, Maria Clara Pessoa; Costa, José Lino; Martins, Gabriel G.Batrachoidids, which include midshipman and toadfish are less known among embryologists, but are common in other fields. They are characteristic for their acoustic communication, and develop hearing and sound production while young juveniles. They lay large benthic eggs (>5mm) with a thick chorion and adhesive disk and slow development, which are particularly challenging for studying embryology. Here we took advantage of a classical tissue clearing technique and the OPenT open-source platform for optical tomography imaging, to image a series of embryos and larvae from 3 to 30mm in length, which allowed detailed 3D anatomical reconstructions non-destructively. We documented some of the developmental stages (early and late in development) and the anatomy of the delicate stato-acoustic organs, swimming bladder and associated sonic muscles. Compared to other techniques accessible to developmental biology labs, OPenT provided advantages in terms of image quality, cost of operation and data throughput, allowing identification and quantitative morphometrics of organs in larvae, earlier and with higher accuracy than is possible with other imaging techniques.
- Reproductive success in the Lusitanian toadfish : Influence of calling activity, male quality and experimental designPublication . Amorim, Maria Clara Pessoa; Conti, Carlotta; Santos, Carla Sousa; Novais, Bruno; Gouveia, Maria D.; Vicente, Joana R.; Modesto, Teresa; Gonçalves, Amparo; Fonseca, Paulo JorgeAcoustic signals are sexual ornaments with an established role on mate choice in several taxa, but not in fish. Recent studies have suggested that fish vocal activity may signal male quality and influence male's reproductive success but experimental evidence is lacking. Here we made two experiments to test the hypothesis that vocal activity is essential for male breeding success in a highly vocal fish, the Lusitanian toadfish. We first compared the reproduction success between muted and vocal males. In a second experiment we related male reproduction success with acoustic activity and male quality, including biometric, condition and physiological features. As a proxy for reproductive success we tallied both total number and number of sired eggs, which were correlated. Muting experiments showed that successful mating was dependent on vocalizing. In addition, the number of eggs was positively associated with the male's maximum calling rate. In the second experiment male's reproductive success was positively associated with male condition and negatively related with circulating androgen levels and relative gonad mass, but was not associated with vocal activity. Differences in results may be related with nest design which could have influenced mate choice costs and intra-sexual competition. In the muting experiment nests had a small opening that restrained the large nest-holder but allowed smaller fish, such as females, to pass while in the second experiment fish could move freely. These experiments suggest that a combination of factors, including vocal activity, influence reproductive success in this highly vocal species.