UIE-E - Artigos em revistas nacionais
Permanent URI for this collection
Browse
Recent Submissions
- Sexo, mentiras e handicaps: Reflexões sobre os mecanismos de selecção sexualPublication . Oliveira, Rui FilipeNo presente artigo o autor revê os diferentes modelos de selecção sexual, nomeadamente a teoria dos descendentes atractivos, a teoria dos bons genes e a teoria do enviezamento sensorial. E analisado o caso particular da possível acção dos mecanismos de selecção sexual nos sistemas de reprodução em arenas, nas quais os machos se agregam para cortejar, uma vez que estes sistemas potenciam a competição entre os machos e as situações de escolha de parceiros sexuais por parte das fêmeas. Neste contexto é dada especial atenção a dois fenómenos: (a) a possível existência de mecanismos de escolha passivos por parte das fêmeas que gerem padrões consitentes de preferências, como é o caso conhecido das preferências por machos com territórios centrais nas arenas em relação a machos com territórios periféricos; (b) a possibilidade de existirem beneficios não-genéticos para as fêmeas em sistemas de arenas que expliquem os padrões de preferências detectados. Finalmente é discutido o modelo do handicap da imunocompetência e apresentam-se evidências que apontam para um papel dos androgénios como mediadores fisiológicos de qualidades fenotípicas dos machos.
- Sobre o uso de estatística de simulação em estudos de comportamentoPublication . Almada, Vítor Carvalho; Oliveira, Rui FilipeNeste artigo discutimos sucintamente as potencialidades da estatística de simulação nas ciências do comportamento. São apresentadas duas aplicações: uma desenvolvida por Estabrook e Estabrook (1 989) para a análise de tabelas de contingência e uma outra desenvolvida na nossa unidade de investigação para testes de verosimilhança. Ambos os procedimentos superam os problemas de valores esperados baixos que limitam o uso da estatística X2 em muitas circunstâncias, e oferecem ainda a possibilidade de se avaliar a significância de células/classes específicas. ------- ABSTRACT ------ In this paper we discuss briefly the potential of simulation statistics in the behavioural sciences. We present two applications: one developed by Estabrook and Estabrook ( 1989) for the analysis of contingency tables and another developed in our research unit for goodness-of-fit tests. Both procedures overcome the problems of low expected values that limit the use of X2 statistic in many ciscunstances, and offer the possibility of assessing the significance of specific cells/ /classes.
- The study of inshore fishes in Portugal - A brief history and prospects for the futurePublication . Almada, Vítor Carvalho; Henriques, Miguel; Gonçalves, Emanuel JoãoInexistente
- 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.
- 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.
- The courtship behaviour of the pipefish Nerophis lumbriciformis: Reflections of an adaptation to intertidal lifePublication . Monteiro, Nuno Miguel; Vieira, Maria Natividade; Almada, Vítor CarvalhoThe courtship behaviour of Nerophis lumbriciformis (Pisces: Syngnathidae) consists of three distinct phases (initial courtship, spawning, and embrace) marked by prominent behavioural changes. The first courtship phase is characterised by female quivering. Courtship activity increases from low to high levels of quivering, causing undulatory head movements in the female. In the second phase, the female transfers her eggs onto the male incubating ventral surface. During the final phase, the male wraps his body around the female (embrace). Females actively initiate courtship indicating that these pipefishes are courtship role reversed. The complete lack of swimming and vertical movements in the courtship behaviour of N. lumbriciformis, unlike in the behaviour of other syngnathid species, suggests an adaptation to intertidal conditions.
- Some features of the behaviour of the marbled newt Triturus marmoratus (Latreille, 1800) in captivityPublication . Robalo, Joana Isabel; Almada, Vítor CarvalhoThe behaviour in groups of both sexes of marbled newts (Triturus marmoratus) from Sintra, Portugal, kept for a few weeks in a large aquarium, is described. Behaviour patterns described for this species and for other species in this genus were recognised. The following behaviours are described for the first time: Walk-over, Land-over, Stand-on, Show, Erect-body, Yawn, Circle, and Dig. Females seem to have a more active role in courtship than is usually considered. The behaviour frequencies for each sex were analysed using simulation statistics. Some elements usually classified as male sexual behaviours occur in both sexes and are likely to play other social roles.
- Short-term social modulation of 11-ketotestosterone levels in males of the cichlid fish Oreochromis mossambicus during male-female interactionsPublication . Borges, Rita Alexandra; Oliveira, Rui Filipe; Almada, Vítor Carvalho; Canário, Adelino V. M.After 48 hours of social isolation male individuals of Oreochromis mossambicus were allowed to interact with a conspecific female in the same aquarium during a period of up to six hours. Colouration exhibited, and frequencie countering and agonistic behaviours performed by the males were recorded before and after social isolation (T0) and six hours after the introduction of the female (T6). Male androgen (testosterone and 11-ketotestosterone, 11-KT) concentrations measured in the urine, at T0 were not correlated to subsequent levels of agonistic and sexual behaviours. However, behavioural interactions were correlated to 11-KT levels at T6. These results suggest a short-term social modulation of 11-KT levels by male-female interaction.
- 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.