BCOMP - Artigos em revistas internacionais
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- A simple method using a single video camera to determine the three-dimensional position of a fishPublication . Pereira, Pedro; Oliveira, Rui FilipeIn the present paper, we describe a method for recording the coordinates of a fish in an aquarium in a three-dimensional space, using a single video camera and a mirror. Weuse photogrammetic equations for this, considering the image obtained in the mirror as a virtual image obtained by a second camera. Atransformation of the coordinate system is required to express the obtained coordinates in an x, y, z system defined by the edges of the aquarium. The accuracy of the proposed method was estimated, and errors in extreme conditions were found to be 0.8% to 1.2 %, compared with the dimensions of the aquarium used in the test.
- A revision of the status of Lepadogaster lepadogaster (Teleostei: Gobiesocidae): sympatric subspecies or a long misunderstood blend of species?Publication . Henriques, Miguel; Lourenço, Rita; Almada, Frederico José Oliveira de; Calado, Gonçalo; Gonçalves, David; Guillemaud, Thomas; Cancela, M. Leonor; Almada, Vitor CarvalhoMolecular (partial mitochondrial 12S ribosomal DNA sequences), morphological and meristic analysis of Lepadogaster lepadogaster lepadogaster, L. l. purpurea and L. zebrina were performed to investigate the relationships between these taxa. On the western shore of mainland Portugal, where the two subspecies of L. lepadogaster occur sympatrically, they differ in microhabitat preferences and their breeding seasons are largely out of phase. This information, combined with data on distribution patterns, led to the following conclusions: Lepadogaster l. purpurea is considered to be a valid species, L. purpurea (Bonnaterre, 1788), different from L. l. lepadogaster, now designated L. lepadogaster (Bonnaterre, 1788). L. zebrina was found to be a synonym of L. lepadogaster. The two newly defined species were found to be in sympatry at Madeira and the Canary islands, the Atlantic coast of the Iberian Peninsula, and the Mediterranean at least as far as Genoa (Italy). Diagnostic characters and a list of synonyms are provided.
- Genetic structure and historical demography of the shanny Lipophrys pholis in the Portuguese coast based on mitochondrial DNA analysisPublication . Francisco, Sara Martins; Vieira, Maria Natividade; Almada, Vítor CarvalhoInexistente
- Ontogenetic development of Parablennius pilicornis (Pisces: Blenniidae) in controlled conditionsPublication . Faria, Claudia; Gil, Fátima; Almada, Vitor CarvalhoThe full developmental sequence from egg to juvenile of Parablennius pilicornis in controlled conditions is described. Embryonic development lasted 9 days at 18.0 to 21.0°C, 14 days at 17.0 to 20.0°C, 16 days at 16.0 to 19.0°C and 17 days at 14.0 to 18.5°C. Newly hatched larvae measured 3.1 mm total length (TL), had the mouth and anus open, pigmented eyes, almost no yolk, and the pectoral fins were small and unpigmented. Most larvae settled between day 66 and 69 after hatching (27.0 mm TL) and showed full juvenile pigmentation patterns between day 91 and 93 (30.0 mm TL). However, on day 61/62 after hatching (when they were more than 25.0 mm) they began to show a complex agonistic repertoire.
- Effects of ship noise on the detectability of communication signals in the Lusitanian toadfishPublication . Vasconcelos, Raquel Ornelas; Amorim, Maria Clara Pessoa; Ladich, FriedrichUnderwater noise pollution is an increasing environmental problem which might affect communication, behaviour, fitness and consequently species' survival. The most common anthropogenic noises in aquatic habitats derive from shipping. In the present study we investigated the implications of noise pollution from a ship on the sound detectability, namely of conspecific vocalizations in the Lusitanian toadfish, Halobatrachus didactylus. Ambient and ferry-boat noises were recorded in the Tagus River estuary (Portugal), as well as toadfish sounds, and their sound pressure levels determined. Hearing sensitivities were measured under quiet lab conditions and in the presence of these masking noises at levels encountered in the field, using the auditory evoked potentials (AEP) recording technique. The Lusitanian toadfish is a hearing generalist, with best hearing sensitivity at low frequencies between 50 and 200 Hz (below 100 dB re. 1 microPa). Under ambient noise conditions, hearing was only slightly masked at lower frequencies. In the presence of ship noise, auditory thresholds increased considerably, by up to 36 dB, at most frequencies tested. This is mainly because the main energies of ferry-boat noise were within the most sensitive hearing range of this species. Comparisons between masked audiograms and sound spectra of the toadfish's mating and agonistic vocalizations revealed that ship noise decreased the ability to detect conspecific acoustic signals. This study provides the first evidence that fishes' auditory sensitivity can be impaired by ship noise and that acoustic communication, which is essential during agonistic encounters and mate attraction, might be restricted in coastal environments altered by human activity.
- Postconflict behaviour in brown capuchin monkeys (Cebus apella)Publication . Daniel, João Rodrigo; Santos, António José; Cruz, Mónica GuimarãesPostconflict affiliation has been mostly studied in Old World primates, and we still lack comparative research to understand completely the functional value of reconciliation. Cebus species display great variability in social characteristics, thereby providing a great opportunity for comparative studies. We recorded 190 agonistic interactions and subsequent postconflict behaviour in a captive group of brown capuchin monkeys ( Cebus apella) . Only 26.8% of these conflicts were reconciled. Reconciliation was more likely to occur between opponents that supported each other more frequently and that spent more time together. Postconflict anxiety was mostly determined by conflict intensity, and none of the variables thought to measure relationship quality had a significant effect on postconflict stress.
- A behavioral perspective on the biophysics of the light-dependent magnetic compass: a link between directional and spatial perception?Publication . Phillips, John B.; Muheim, R.; Jorge, P. E.In terrestrial organisms, sensitivity to the Earth's magnetic field is mediated by at least two different magnetoreception mechanisms, one involving biogenic ferromagnetic crystals (magnetite/maghemite) and the second involving a photo-induced biochemical reaction that forms long-lasting, spin-coordinated, radical pair intermediates. In some vertebrate groups (amphibians and birds), both mechanisms are present; a light-dependent mechanism provides a directional sense or 'compass', and a non-light-dependent mechanism underlies a geographical-position sense or 'map'. Evidence that both magnetite- and radical pair-based mechanisms are present in the same organisms raises a number of interesting questions. Why has natural selection produced magnetic sensors utilizing two distinct biophysical mechanisms? And, in particular, why has natural selection produced a compass mechanism based on a light-dependent radical pair mechanism (RPM) when a magnetite-based receptor is well suited to perform this function? Answers to these questions depend, to a large degree, on how the properties of the RPM, viewed from a neuroethological rather than a biophysical perspective, differ from those of a magnetite-based magnetic compass. The RPM is expected to produce a light-dependent, 3-D pattern of response that is axially symmetrical and, in some groups of animals, may be perceived as a pattern of light intensity and/or color superimposed on the visual surroundings. We suggest that the light-dependent magnetic compass may serve not only as a source of directional information but also provide a spherical coordinate system that helps to interface metrics of distance, direction and spatial position.
- Gulls can change their migratory behavior during lifetimePublication . Marques, Paulo A. M.; Sowter, David; Jorge, PauloMigration is a widespread phenomenon among birds and is likely to be subject to strong selective pressures. Birds’ annual routines and behaviors might be expected to change during their diff erent life history stages, resulting in diff erent, agerelated migration patterns. However, although migration has been the subject of many publications, age-related diff erences in migration have received little attention. Th e present study examined age-related changes in individual migration habits in lesser black-backed gulls, Larus fuscus. We analyzed data from 10-year (1998–2007) color-ringing project in NW England, comprising more than 10 000 ringed individuals. Our results showed a latitudinal cline in age structure across the wintering range, with adults and gulls in their fi rst breeding year wintering closer to the breeding grounds. Supporting this result we observed that individuals, as they get older, changed the migration behavior and winter closer to the breeding areas. Interestingly, we found no diff erences in survival rates across the wintering grounds. Th us diff erences in survival rates can not account for the latitudinal cline in age structure, and the observed fi ndings seem to be best explained by the arrival time hypothesis, based on a mechanism whereby individuals are able to change their migratory behavior as result of the onset of sexual maturity and associated mating pressures.
- Lusitanian toadfish song reflects male qualityPublication . Amorim, M. C. P.; Simoes, J. M.; Mendonca, N.; Bandarra, Narcisa M.; Almada, Vítor Carvalho; Fonseca, P. J.Lusitanian toadfish males that provide parental care rely on acoustic signals (the boatwhistle) to attract females to their nest. We test the hypothesis that male quality, namely male size and condition that are relevant for parental success, is reflected in vocal activity and boatwhistle characteristics and thus advertised to females. We recorded 22 males over a week during the peak of the breeding season. Calling rate and calling effort (percentage of time spent calling) strongly reflected male condition (lipid content of somatic muscles) and to a smaller extent sonic muscle hypertrophy and larger gonads. Males in better condition (increased body lipid and relative higher liver mass) also contracted the sonic muscles at faster rate as shown by the shorter boatwhistle pulse periods. Amplitude modulation reflected the degree of sonic muscle hypertrophy. None of the measured male quality parameters were good predictors of boatwhistle duration and dominant frequency. Altogether this study strongly suggests that Lusitanian toadfish males advertise their quality to females primarily with boatwhistle calling rate and calling effort, which mainly reflect male condition. Because pulse period had low variability, consistent with the existence of a vocal central pattern generator, we suggest that males that sustain sonic muscles contraction at a very fast rate close to their physiological limit may be honestly advertising their quality (condition). Similarly, males that produce boatwhistles with higher amplitude modulation, a feature that seems dependent on sonic muscle hypertrophy, could be more attractive to females.
- Sex differences in the dorsolateral telencephalon correlate with home range size in blenniid fishPublication . Costa, Silvia S.; Andrade, Rui; Carneiro, Luís Alberto; Gonçalves, Emanuel João; Kotrschal, Kurt; Oliveira, Rui FilipeBlenniid fish exhibit a polygynandric mating system with parental care restricted to males. Nest-holder males defend a breeding territory centered on their nest, usually a crevice or hole in a rocky substrate, to which they attract females to spawn. Females, on the other hand, must search for nests in order to spawn and usually are the choosy sex, producing several sequential egg batches and broods during the breeding season. Therefore, male blennies are more site-attached than females. This situation offers an opportunity to investigate potential neural correlates of intraspecific differences in selective pressures for different spatial abilities in these species. Since the dorsolateral telencephalon has been considered a teleost homologue of the mammalian hippocampus, we predicted that the spatial abilities required for females to locate and return accurately to nests of males may have produced a sex difference in the size of the telencephalic nuclei involved in spatial abilities, biased towards females. To test this hypothesis, we assessed the home ranges and measured the size of the dorsolateral telencephalon of both sexes during the breeding season in two blenniid species, the shanny (Lipophrys pholis) and the Azorean rock-pool blenny (Parablennius parvicornis) . We chose these two species because they differ in the degree of chemical communication they use, and this could also lead to differences in telencephalic areas. As predicted, in both species females present considerably larger home ranges paralleled by larger dorsolateral ventral telencephalic nuclei (DLv) than males. Other telencephalic nuclei that were measured did not show any sex difference in size. These results suggest that the DLv is involved in spatial abilities in blenniid fish and that sexual selection may be promoting this divergence as already described for mammals and birds.