Consulta: subjectFacets:"Sex-ratio"
Registros recuperados: 10
Data/hora: 01/06/2024 10:17:53

Etude cytologique de la gamétogenèse, de la sex-ratio et du cycle de reproduction chez l'huître perlière Pinctada margaritifera (L) var. cumingii (Jameson), (mollusques, bivalves). Comparaison avec le cycle de Pinctada maculata (Gould)
Provedor de dados: 5
Autores: Thielley, Maryse.
The population of Pinctada margaritifera and Pinctada maculata lay eggs throughout the year. Temperature variations induce huge but asynchronous laying. Preferential periods of gonad maturity correspond to the season changings in both species. However. some differences between the two specics are noticed. Both species are protandric hermaphrodites. Female condition is unstable: a reversion to the male condition may be observed and is probably linked with stress. The average size for the first sexual maturation as weil as for sexual conversion are specified in P. margaritifera. The breeding conditions induce modifications in some reproductive cycle processes (maturation, sex-ratio). Some conditions suitable for reproduction may become unfavorable to...
Tipo: Text
Palavras-chave: Gamétogenèse; Cycle de reproduction; Sex-ratio; Pinctad margaritifera; Mollusque; Bivalve; Huître perlière; Gametogenesis; Reproductive cycle; Sex-ratio; Pinctada margaritifera; Mollusca; Bivalvia; Pearl oyster.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00440/55208/56677.pdf

Additive transcriptomic variation associated with reproductive traits suggest local adaptation in a recently settled population of the Pacific oyster, Crassostrea gigas
Provedor de dados: 5
Autores: Sussarellu, Rossana; Huvet, Arnaud; Lapegue, Sylvie; Quillen, Virgile; Lelong, Christophe; Cornette, Florence; Jensen, Lasse Fast; Bierne, Nicolas; Boudry, Pierre.
Background Originating from Northeast Asia, the Pacific oyster Crassostrea gigas has been introduced into a large number of countries for aquaculture purpose. Following introduction, the Pacific oyster has turned into an invasive species in an increasing number of coastal areas, notably recently in Northern Europe.  Methods To explore potential adaptation of reproductive traits in populations with different histories, we set up a common garden experiment based on the comparison of progenies from two populations of Pacific oyster sampled in France and Denmark and their hybrids. Sex ratio, condition index and microarray gene expression in gonads, were analyzed in each progeny (n = 60).  Results A female-biased sex-ratio and a higher condition index were...
Tipo: Text
Palavras-chave: Crassostrea gigas; Adaptation; Invasiveness; Fertility; Sex-ratio; Transcriptome; Microarray.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00287/39829/38343.pdf

Exploitation et structure des anguilles de dévalaison dans les lagunes aménagées du bassin d'Arcachon
Provedor de dados: 5
Autores: Lee, Tae-won.
The fishing by the sluice, employed in the brackish fish ponds of Arcachon Bay, catchs only the migrating eels. The exploitation by this process is not more than the 18 percent of the biomass. The structure of the migrating eels caught in winter 1977-78 was estimated using the double sampling method with length as strata. The sex­ratio was about 1.1. The males migrate to the sea from 3 to 7 years after of the brackish water life (maximum 5 years old) and the females leave the fish ponds, generally from 5 to 9 years after (maximum 7 years old). The estimated mean lengths, 37.5 cm for the males and 49.8 cm for the females, were much smaller than-those which were estimated in the Italian "Vallis"
Tipo: Text
Palavras-chave: Pêche à l'écluse; Exploitation; Anguilles de dévalaison; Double échantillonnage; Sex-ratio; Structure d'âge; Taille moyenne; Fishing by the sluice; Exploitation; Migrating eels; Double sampling; Sex-ratio; Age composition; Mean length.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/00306/41684/40893.pdf

Sex determination in the oyster Crassostrea gigas - A large longitudinal study of population sex ratios and individual sex changes
Provedor de dados: 5
Autores: Broquard, Coralie; Martinez, Anne-sophie; Maurouard, Elise; Lamy, Jean-baptiste; Dégremont, Lionel.
Understanding sex determination in the Pacific oyster Crassostrea gigas, a sequential hermaphrodite, can provide prospective on the evolution of sex-determining systems for comparative reproduction from an evolutionary perspective. Surprisingly, this mechanism is still poorly understood. To date, sex ratio and sex change have never been studied at the individual level for a large size group and long-term monitoring. To this purpose, we performed an ambitious individual long-term follow-up (6 years) on a large population (cohort 1: 7488 oysters) produced from wild oysters, as well as for a second population produced from the cohort 1 (cohort 2: 4320 oysters). All oysters were individually sexed from 2014 to 2019. For the cohort 1, our results showed a...
Tipo: Text
Palavras-chave: Sex-ratio; Sex change; Oysters; Hermaphroditism; Crassostrea gigas.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00587/69868/67845.pdf

What happened in the North?: Servants and rural workers in Norway
Provedor de dados: 125
Autores: Miscali,Monica.
The aim of this article is to investigate the situation of the rural servants in Norway from the preindustrial period, the rural Norway, to industrialisation in the middle of XIX century. I will summarise the research that has been carried out in Norway. In particular I will describe the evolution of the servant&amp;#8217;s role and tasks, underlining the transformations and passages from an agrarian society to an industrial one and the importance of the service activities from a demographic prospective. Furthermore I will describe the gender roles, the sex-ratio, the differences between male and female servants and the differences in the treatment they received. I will contextualise the case of Norway and see if there were similitudes or differences in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Norway; Domestic service; Servants role; Sex-ratio; Rural servants.
Ano: 2017
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1515-59942017000300002

Reproduction de Ethmalosa fimbriata (Bowdich) en lagune Aby (Côte d'Ivoire)
Provedor de dados: 20
Autores: N'goran, Ya Nestor.
Ethmalosa fimbriata (Bowdich) est un clupeidé très abondant dans les pêcheries artisanales ivoiriennes. Il représente plus de 60% des captures lagunaires. En lagune Aby, la taille de première maturité sexuelle se situe à 9.6cm pour le mâle et 9.9cm pour la femelle. La reproduction a lieu deux fois dans l'année pendant les saisons à relativement haute salinité, de février à mai et de juillet à août. Cette reproduction n'affecte pas de façon significative le sex-ratio dont la moyenne varie de 35% à 36% selon la période. La fécondité absolue est très fluctuante et varie de 11.000 à 148.000 oeufs par femelle.
Tipo: Journal Contribution
Palavras-chave: Reproduction; Cycle sexuel; Sex-ratio; Fécondité.
Ano: 1991
URL: http://hdl.handle.net/1834/5060

Relative growth and population dynamics of Macrobrachium iheringi (Decapoda, Palaemonidae)
Provedor de dados: 84
Autores: Nogueira,Caio dos Santos; Perroca,Júlia Fernandes; Piantkoski,Emerson Luiz; Costa,Rogerio Caetano da; Taddei,Fabiano Gazzi; Fransozo,Adilson.
Abstract During the ontogenetic development of crustaceans, the relative growth of some structures may change, especially during the transition from juvenile to adult. This study describes the relative growth of body structures of Macrobrachium iheringi, and provides information on its population dynamics, such as structure, fecundity, and morphological sexual maturity. The sampling of M. iheringi was carried out in “Ribeirão da Hortelã”, in Botucatu (SP, Brazil). The length of the carapace (CL), abdomen (AL), and ischium (IL), merus (ML), carpus (CrL), propodus (PpL), and dactyl (DcL) of the second right pereopod were measured. In addition, the width of the second abdominal pleura (PW) and propodus height (PpH) were included in analyses. The relationships...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Allometry; Freshwater; Caridea; Populations; Sex-ratio.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492019000100208

Biologia populacional de Emerita brasiliensis Schmitt (Crustacea, Hippidae) na Praia Vermelha do Norte, Ubatuba (São Paulo, Brasil)
Provedor de dados: 104
Autores: Nakagaki,Jelly Makoto; Pinheiro,Marcelo Antonio Amaro.
Emerita brasiliensis Schmitt, 1935 is a common mole crab called "tatuíra" in Brazil, with distribution from Espírito-Santo State (Brazil) to Buenos Aires Province (Argentina). Specimens were collected bimonthly from May/1992 through March/1993 with 4mm siffers mesh, in the intertidal region at Vermelha do Norte Beach, Ubatuba, São Paulo, Brazil. The animals were sexed and measured with a precision caliper of 0.1 mm (Cl = carapace length). Males presented cl amplitude from 3.4-17.3mm (13.2±2.1mm), and females from 13.8-26.3mm (20.5±1.8mm), showing a well-defined sexual dimorfism for this variable. The population presented a smaller incidence of males in relation to females (0.54:1.00), however in May/1992 an inverse pattern occurred (1.84:1.00). Ovigerous...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hippidae; Emerita brasiliensis; Population structure; Sex-ratio.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751999000600010

Population dynamics and reproductive phenology of a harvestman in a tidal freshwater wetland
Provedor de dados: 42
Autores: IGLESIAS,PATRICIA P.; PEREYRA,MARTÍN O.
Abstract  There is a great amount of ecological information for terrestrial arthropods in several types of habitats, but few studies have focused on populations living in tidal freshwater wetlands. During a two-year field survey, we studied the temporal dynamics of the harvestman Discocyrtus prospicuus inhabiting a freshwater wetland exposed to predictable tides and unpredictable floods. We also explored the effects of temperature, precipitation, and tide level on the population dynamics and reproductive phenology. Our findings are markedly different from those reported in other harvestman species living in different habitats and also from conspecific populations living in the mainland. Adults, subadults, and juveniles remain active throughout the year,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Abiotic factors; Breeding season; Phenology; Sex-ratio; Unpredictable floods.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652020000100710

Relationship between number of ovipositions of Cotesia flavipes (Cam.) and number of descendants emerged from its host Diatraea saccharalis (Fabr.)
Provedor de dados: 44
Autores: Yamauchi,Meire N.; Gobbi,Nivar; Chaud-Netto,José; Campos-Farinha,Ana E.
Females of Cotesia flavipes (Cam.) were individually introduced into Petri dishes containing one larva of its host Diatraea saccharalis (Fabr.). Each C. flavipes female was allowed to oviposit once or twice in the same larva. Time of emergence of larvae and adults, sex-ratio, number of non-viable larvae and pupae, and longevity of adults of C. flavipes were recorded. Data revealed that two successive ovipositions in the host did not affect sex-ratio, but increased number of parasitoids and number of non-viable larvae and pupae.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Insecta; Parasitoid; Superparasitism; Sex-ratio; Viability.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0301-80591997000100012