UIE-E - Artigos em revistas nacionais
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- Agonistic behaviour and control of access to hiding places in two intertidal blennies, Lipophrys pholis and Coryphoblennius galerita (Pisces: Blenniidae)Publication . Faria, Cláudia Barreiros Macedo de; Almada, Vítor CarvalhoIn this study we investigated the relationships between dominance rank and access to shelters in captive groups of Lipophrys pholis and Coryphoblennius galerita, as well as the effects of group size and shelter availability. Dominance rank was strongly correlated with size in juvenile L. pholis and with sex and size in adult C. galerita, males being dominant over females of similar size. Access to shelters was significantly correlated with dominance rank. For both species, most interactions occurred out of shelters. Direct disputes over shelters were always initiated by the dominant fish and the initiator was always the winner. The rate of aggression per fish per unit time decreased with an increase in the number of fish in L. pholis but not in C. galerita. No significant differences were found in groups differing in the number of shelters. C. galerita showed a higher rate of agonistic interactions and a higher proportion of overt aggression than L. pholis. It is suggested that one of the functions of agonistic interactions in these fishes is the control of a set of shelters, in the network of pathways used by each individual within its home range, minimising the time required to hide in case of danger.
- Analysis of conditional contingency using ACTUS2 with examples from studies of animal behaviorPublication . Estabrook, George F.; Almada, Vítor Carvalho; Robalo, Joana IsabelIn this paper we present ACTUS2, the second version of ACTUS (Analysis of Contingency Tables Using Simulation). ACTUS2 has many new features, including analysis of data in which dependencies that make some combinations of properties impossible are hypothesized. Because ACTUS2 explicitly simulates such hypotheses, it can be used without loss of accuracy to analyze small amounts of data in large tables with many zeros or very low frequencies. We illustrate these features with two studies of animal behavior: interactions of male individuals with other individuals in groups of captive, mature Triturus marmoratus pygmaeus (newts); and agonistic interactions between pairs of male juvenile Diplodus sargus (the sparid fish, white sea-bream). Both significantly frequent, and significantly infrequent, co-occurrences that had biologically meaningful interpretations were revealed.
- A checklist of the blennioid fishes (Teleostei, Blennioidei) occurring in Portuguese watersPublication . Oliveira, Rui Filipe; Almada, Vítor Carvalho; Almeida, Armando J.; Santos, Ricardo Serrão; Gonçalves, Emanuel JoãoTwenty species of blennioide fishes have been cited from Portuguese waters. A survey of the published literature and personal observations by the authors allowed to confirm the presence of eighteen species: Clinitrachus argentatus, Labrisomus nuchipinnis, Tripterygion delaisi, Blennius ocellaris, Coryphoblennius galerita. Lipophrys canevae, L. dalmatinus, L. pholis, L. trigloides, Parablennius gattorugine, P. pilicornis, P. rouxi, P. ruber, P. incognitus, P. sanguinolentus-parvicornis, Salaria fluviatilis, S. pavo and Ophioblennius atlanticus atlanticus. A check-list is provided with information on the geographic distribution of the confirmed occurences of the blennioid species in portuguese waters.
- Chorusing by male european fiddler crabs, Uca tangeri: A study of visual communication netwoksPublication . Burford, Fiona R. L.; McGregor, Peter K.; Oliveira, Rui FilipeChorusing behaviour, in which males aggregate and advertise to attract females, has been extensively studied in acoustically signalling orthopterans and anurans. Species which agregate and signal visually have comparanble behaviour but chorusing aspects has been studied infrequently. Male fiddler crabs (genus Uca) signal by waving and enlarged claw and form signalling aggregations, therefore, they have a potential to form a visual chorus. This study investigated the chorusing behaviour of male eurpoean fiddler crabs, Uca tangeri. The timing of waving by groups of three males (trios) was studied when each male was alone and when all three males were present. When waving in a trio, the male with the largest claw significantly increased the lenght of its interwave interval and some such males tend to wave soon after the other males. This pattern of waving may enhance the effectiveness of the large-claw males signal by avoiding visual object grouping and by allowing females to assess relative claw size more readily.
- Considerations on the use of video playbacks as visual stimuli: The Lisbon workshop consensusPublication . Oliveira, Rui Filipe; Rosenthal, Gil G.; Schlupp, Ingo; McGregor, Peter K.; Cuthill, Innes C.; Endler, John A.; Fleishman, Leo J.; Zeil, Jochen; Barata, Eduardo Nuno; Burford, Fiona R. L.; Gonçalves, David; Haley, Michael; Jakobsson, Sven; Jennions, Michael D.; Körner, Kay; Lindström, Leena; Peake, Thomas; Pilastro, Andrea; Pope, Denise S.; Roberts, Sam G. B.; Rowe, Candy; Smith, Jerome; Waas, Joseph R.This paper is the consensus of a workshop that critically evaluated the utility and problems of video playbacks as stimuli in studies of visual behavior. We suggest that video playback is probably suitable for studying motion, shape, texture, size, and brightness. Studying color is problematic because video systems are specifically designed for humans. Any difference in color perception must lead to a different color sensation in most animals. Another potentially problematic limitation of video images is that they lack depth cues derived from stereopsis, accommodation, and motion parallax. Nonetheless, when used appropriately, video playback allows an unprecedented range of questions in visual communication to be addressed. It is important to note that most of the potential limitations of video playback are not unique to this technique but are relevant to all studies of visual signaling in animals.
- Do Cory’s shearwaters Calonectris diomedea synchronize laying among close neighborhoods? A reappraisal using data from artificial nest sitesPublication . Catry, Paulo; Granadeiro, José Pedro; Oliveira, PauloPrevious studies of Cory’s shearwater nesting biology suggest that pairs nesting at very close range to one another lay their eggs more synchronously than the colony as a whole. However, such apparent synchrony could be confounded by the existence of spatial structure in the quality of nesting sites and, hence, quality of the birds occupying the nests. If laying dates differ between sites of different quality, then synchrony is just a by-product of the spatial arrangement of nest sites. In this study, we show that when studying laying dates in artificial nests of uniform quality, no local synchronization of laying could be detected. We point to other shortcomings of previous analyses and conclude that, although Cory’s shearwaters show remarkably synchronized attendance behaviors at the nesting sites, there is no conclusive evidence showing that laying dates are influenced by the behavior of near neighbors.
- Human exploitation of male fiddler crab claws: Behavioural consequences and implications for conservationPublication . Oliveira, Rui Filipe; Machado, José Luis Gorjão H. C.; Jordão, Joana; Burford, Fiona R. L.; Latruffe, Claire; McGregor, Peter K.Male fiddler crabs have one of their feeding claws greatly enlarged, which may comprise up to 40% of their weight. In southern Portugal (Ria Formosa) the major claw of the fiddler crab Uca tangeri is a local delicacy. Fishermen break off the male major claw and throw the crab back into the mudflat to regenerate a new one. Approximately 38 % of the males sampled had a missing or a regenerating claw. Although individuals are not removed from the population the operational sex ratio is biased towards females since other males and females behave towards clawless males as if they were females. Moreover, removing the major claw from males prevents them from signalling (waving display) to females to attract them to their breeding burrows and it also places them at a disadvantage if they have to defend their burrows from males with intact claws. Thus, the harvesting of male fiddler crab claws has potential consequences at the population level. In this paper we investigated these potential consequences by comparing an exploited population of fiddler crabs at Ria Formosa with a remote population at the Mira estuary that is not under human exploitation. The unexploited population has significantly larger males and a significantly higher density of burrows. The operational sex ratio is also significantly different between the two populations with a female-biased sex ratio in the exploited population. These preliminary results suggest that claw harvesting in fiddler crabs has a measurable effect at the population level. The consequences of this type of fishery in which the individuals are not removed from the population but the population structure is potentially affected need further investigation.
- Male display characters, gonadal maturation and androgens in the cichlid fish Oreochromis mossambicusPublication . Oliveira, Rui Filipe; Almada, Vítor CarvalhoThe relationships between gonadal maturation and the expression of behavioral and morphological display characters in O. mossambicus was investigated and the possible role of androgens in the coordination of this process was evaluated using genital papilla size as a bioassay for androgen levels. Morphological and behavioral displaying characters were found to be correlated among themselves. The sexually dimorphic characters were correlated with gonad maturation and androgen levels, but not with the gonado-somatic index. Gonad maturation and androgen levels were closely related. Territoriality and other behavioral variables involved in reproduction were also correlated with gonad maturation and androgen levels. These data suggest that in O. mossambicus androgens play a mediating role between gonadal maturation and the expression of display characters, both morphological and behavioral.
- A new northern limit for the distribution range of Lipophrys canevae (Pisces: Blenniidae) in the Atlantic OceanPublication . Almada, Vítor Carvalho; Oliveira, Rui Filipe; Gonçalves, Emanuel João; Almeida, Armando J.; Barata, Eduardo NunoIn this note, the occurence of Lipophris canevae at Arrábida (Portugal) is reported, which extends 160 Km north the known range ot this species in the Atlantic coast of the Iberian Peninsula. This species has been consistently found at Arrábida since 1987. The presence of a crest on the head of the males, which is considered a rare secondary sexual character in the Mediterranean populations, is very common in the specimens known from portuguese waters, even in the females, where it is vestigial. The meristic and morphometric data from specimens known from portuguese waters are summarized. At Arrábida, the nests occur in the midlittoral zone, often in the transition to the sublittoral, and remain out of water for several hours during low tide. Breeding takes place during Spring and Summer. ------ SUMÁRIO ----- Na presente nota, descreve-se a ocorrência Lipophris canevae na costa da Arrábida (Portugal), o que estende 160 Km para norte e distribuição conhecida para esta espécie na costa atlântica da Península Ibérica. A ocorrência desta espécie na Arrábida tem sido registada regularmente desde 1987. A presença de uma crista na cabeça dos machos, que para as populações mediterrânicas é considerada um carácter sexual secundário raro, ocorre com grande frequência nos espéciemens conhecudis das águas portuguesas, inclusive nas fêmeas embora nestas seja vestigial. Resumem-se os dados merísticos e morfométricos para os exemplares até agora capturados na costa portuguesa. Na Arrábida, os ninhos ocorrem no médio-litoral, por vezes na transição para o infra-litoral, e permanecem emersos durante várias horas na baixa-mar. A reprodução tem lugar na Primavera e Verão.
- On the phylogenetic affinities of Centrolabrus trutta and Centrolabrus caeruleus (Perciformes: Labridae) to the genus Symphodus: Molecular, meristic and behavioural evidencesPublication . Almada, Vitor; Almada, Frederico José Oliveira de; Henriques, Miguel; Santos, Ricardo Serrão; Brito, AlbertoPhylogenetic analysis of partial 12S and 16S mitochondrial rDNA regions, together with meristic and ethological data, has revealed that Centrolabrus trutta (Lowe, 1833), a species occurring in the Canaries and Madeira, and its close relative Centrolabrus caeruleus (Azevedo, 1999) from the Azores, are more closely related to most species of the genus Symphodus than to Centrolabrus exoletus (Linnaeus, 1758). Underwater behavioural observations showed that C. trutta, like C. caeruleus, shares with most Symphodus species sexual dichromatism, male nest building and male parental care of the eggs, traits that are absent in C. exoletus. The low number of base substitutions found between C. trutta and C. caeruleus indicates that these species are very closely related. The 16S rDNA data suggest that C. trutta, C. caeruleus and S. roissali form a monophyletic group. The analysis of the 16S rDNA data also showed that S. melanocercus is the sister species of C. exoletus and it is not closely related to the species of Symphodus included in this study. Lack of nest building and parental behaviour in S. melanocercus, and its marked divergence to other members of the genus Symphodus in meristic characters, also stress its affinity with C. exoletus and its separation from the remaining species of Symphodus. Our data and the evidence available in the literature led us to propose the inclusion of C. trutta and C. caeruleus in the genus Symphodus, while S. melanocercus must be transferred to the genus Centrolabrus.