Sexual differences in parental feeding effort during the nestling period of the White-headed Marsh-Tyrant (Arundinicola leucocephala)

Parental effort may influence the fitness and survivorship of adult birds and their offspring from one breeding season to the next. Although much is known about parental feeding effort in tyrant flycatchers, many species remain understudied. In this study, I examined parental feeding effort of the White-headed Marsh-Tyrant (Awndinicola leucocephala) at a pond in southeastern Brazil. I conducted 10.3 hrs of observations from two locations: a high place with all view of the whole pond, that allowed me to observe flight distances of parents hunting for prey; and from near the nest to observe frequency of visits to the nest. The female marsh-tyrant flew farther while hunting prey and made more visits to the nest than did the male. The adults (mainly the female) provided a variety of terrestrial and aquatic arthropods to the nestlings. Additionally, parents removed fecal sacs from the nest and nestlings eliminated arthropod remains from the nest, the first records of nest sanitation activities by this species. Nonexclusive hypotheses that may explain the lower level of parental care provided by the male include: higher predation risk due its more conspicuous plumage, commitment of male to territory defense, and its selfish behavior influenced by indirect genotype fitness inherited by the offspring. © The Neotropical Ornithological Society.

Influence of the estrous cycle on the behavior of rats in the elevated T-maze

The elevated T-maze is an animal anxiety model which can discriminate between anxiety-like and fear-like behaviors. The estrous cycle is an important variable of the response in animal anxiety tests and is known to affect other models. The aim of the present study was to investigate the influence of the estrous cycle on behavior displayed in the elevated T-maze test. Seventeen male and 60 female rats were submitted to one session in this test, with the females being screened for the estrous cycle and divided into groups according to the various phases. The elevated T-maze had three arms of equal dimensions (50 cm x 10 cm), one enclosed by 40-cm high walls and perpendicular to the others, the apparatus being elevated 50cm above the floor. Each rat was placed in the end of the enclosed arm and the latency for it to leave this arm was recorded. These measurements were repeated three times separated by 30-s intervals (passive avoidance). After trial 3, each rat was placed at the distal end of the right open arm and the latency to exit this arm was recorded. Whenever latencies were greater than 300 s the trial was finished. The results demonstrated females in diestrus exhibited anxiety-like behaviors while females in metaestrus behaved in a similar way as the males. There were no differences between groups in fear-like behaviors. The results also indicate the elevated T-maze to be a sensitive test to measure anxiety. (C) 2004 Elsevier B.V. All rights reserved.

Compared morphology of the immatures of males of two urban ant species of camponotus

The immatures of males of two species of Camponotus ants (Hymenoptera: Formicidae) are described and compared by light and electron microscopy. The numbers of larval instars were determined: Camponotus rufipes Fabricius (Hymenoptera: Formicidae) have four instars; and Camponotus vittatus Forel have three. Male larvae of the two species are similar to previously described Camponotus larvae, sharing the following traits: basic shape of body and mandible, presence of 'chiloscleres', 'praesaepium' (some specimens), labial pseudopalps, and ten pairs of spiracles. However, larvae of the two species can be separated by bodily dimensions and based on their hair number and types. Worker larvae of C. vittatus previously described are extensively similar to male larvae, with only a few inconspicuous differences that may result from intraspecific variation or sexual differences.

Sexualidade(S) em cena: as contribuições do discurso audiovisual para a problematização das diferenças no espaço escolar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo da musculatura associada à alimentação entre as raias-viola Rhinobatos percellens e Zapteryx brevirostris (Chondrichthyes, Rhinobatidade)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Processos de construção e representação da identidade feminina em contos de Kate Chopin

Pós-graduação em Estudos Literários - FCLAR

Desenvolvimento morfológico dos ovários em embriões e fetos bovinos da raça Nelore

Pós-graduação em Zootecnia - FCAV

The hypotensive effect of the ruthenium complex [Ru(terpy)(bdq)NO](3+) is higher in male than in female spontaneously hypertensive rats (SHR)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dimorfismo sexual da traquéia e siringe de periquito (Touist sp.)

Investigaram-se as diferenças morfológicas da siringe do periquito Touist sp, cinco machos e cinco fêmeas. A traquéia e a siringe foram dissecadas com o auxílio de uma lupa estereoscópia e avaliaram-se o número de anéis, o comprimento da traquéia e da siringe e o comprimento e espessura do músculo traqueolateral. A traquéia do macho apresentou maior número de anéis e maior comprimento que a das fêmeas. O músculo traqueolateral dos machos é mais vigoroso e origina-se no 43º anel traqueal enquanto o das fêmeas origina-se no 30º anel traqueal e se insere no primeiro anel bronquial. A siringe do piriquito é constituída por anéis craniais, cinco nos machos e três nas fêmeas, anéis intermediários, com formato semelhante a uma bolha sulcada ventralmente, anéis caudais, quatro em ambos os sexos, e pessulo. O dimorfismo sexual está presente na morfometria da musculatura e das cartilagens, o que reflete no canto mais vigoroso dos machos.

Influência do dimorfismo sexual sobre a morfologia da siringe de galinha d'angola (Numida meleagris)

Este estudo teve como objetivo realizar uma descrição morfológica e comparativa da siringe, órgão responsável pelo canto das aves, na espécie Numida meleagris. Para isso foram utilizados cinco machos e cinco fêmeas de galinha d'angola, a fim de verificar a sintopia (traquéia, músculos traqueais) e o dimorfismo sexual da siringe. Verificou-se que a siringe se localiza na bifurcação da traquéia e apresenta maior número de cartilagens nos machos. Nos machos, a inserção do músculo traqueal lateral bem como a origem do músculo esterno traqueal localizam-se mais caudalmente e são mais largos em relação às fêmeas. As diferenças existentes entre machos e fêmeas de galinha d'angola revelam a elevada capacidade das fêmeas em produzir sons semelhantes a tô fraco enquanto que os machos emitem arrulhos e cacarejos.

Diferentes granulometrias de rações sobre o ganho de peso, crescimento, sobrevivência e reversão sexual para tilápias-do-Nilo (Oreochromis niloticus)

The aim of this work was to evaluate the effects of three different diameters of crumble diets (0.25, 0.35 and 0.50 on weight gain, growing, survival and sexual proportion to Nile tilapia (Oreochromis niloticus) larvae with 30, 60 and 90 days of age. In the first 30 days of age larvae were submitted to sex reversion with diets containing the hormone 17[alpha]-methyltestosterone in a dosage of 60mg/kg of ration, respecting the different diameters and after this period, larvae were measured, weighed and counted for calculation of survival taxes. For the biometrical parameters as weight total length a completely randomized design was used in subdivided installments with three treatments and repetitions, considering installments the three diameters of diet and the sub installments, the three ages. In the end of this study, fish fed with diets of grain diameters 0.35 and 0.25 mm obtained the best results for weight gain (14.42g and 13.36 g) and total length (83.13 mm and 82.72 mm), although these results were not statistically significant, and with grain diameters 0.50 and 0.35 mm resulted in 96,66 % and 93,33% of males, respectively, after histological an, of gonads, without statistics differences between the treatments.

Genetic and environmental effects on sexual precocity traits in Nellore cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sexual distinction between 5th instar nymphs of six species of Triatominae (Hemiptera, Reduviidae)

The aim of this paper is to present the analysis of sexual morphological differences observed in 5th instar nymphs of the following species: Panstrongylus megistus; Rhodnius neglectus; Triatoma brasiliensis; T. infestans; T. matogrosensis and T. tibiamaculata. Male and female nymphs were examined and photographed with a Scanning Electron Microscope. The 9th segment dimensions of dorsal and ventral faces were determined through a Profile Projector. Results and statistical analysis showed significant differences: the 9th sternite is significantly broader in male than female nymphs, while in five species; tergites in female nymphs are broad and in male are narrow.

Relative growth, morphological sexual maturity, and size of Macrobrachium amazonicum (Heller 1862) (Crustacea, Decapoda, Palaemonidae) in a population with an entirely freshwater life cycle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gender differences in obsessive-compulsive disorder: a literature review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)