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| Registros recuperados: 84 | |
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| Zanatta, Naiara; Universidade Estadual de Maringá; Cionek, Vivian de Mello; Universidade Estadual de Maringá; Benedito, Evanilde; Universidade Estadual de Maringá. |
| This study aimed to characterize the reproductive strategies of fish from first order streams. Samplings were performed every three months from June 2008 to March 2009, using electric fishing at three streams: Conceição, Scherer and Jurema, located in the municipalities of Diamante do Norte and Amaporã, Paraná State, Brazil. We obtained the total weight (g), standard or total length (cm), sex and maturation stage for each specimen. Limnological data were obtained with portable equipments. The minimum length at first maturation was established for each population, and reproduction period was determined by analyzing the distribution of maturation stages. The sex ratio was obtained and tested (X2) for significant differences. Eight species were analyzed and... |
| Tipo: Reprodução |
Palavras-chave: 2.00.00.00-6 upper Paraná river basin; Sex ratio; Conservation unit; Reproductive stages 2.05.02.00-1. |
| Ano: 2013 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/10932 |
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| COLLA,MARÍA FLORENCIA; CÉSAR,INÉS I.. |
| Abstract: Freshwater amphipods of the genus Hyalella have a great importance in aquatic ecosystems due to their role in matter and energy cycling and its utilization as bioindicators of environmental health. The aim of this work was to analyze relevant population parameters of Hyalellapampeana, such as population density and structure, individual body size, sex ratio, fecundity and recruitment, and to study the possible relation of these parameters to variations in environmental variables. Samples were taken monthly during a one-year period (2006) at three small ponds in the Natural Reserve Island of Martín García, Argentina. The inland aquatic environments showed distinctive physicochemical characteristics, mainly related to pH and conductivity values.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Freshwater amphipoda; Body size; Fecundity; Sex ratio. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000100620 |
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| Valenzuela,Carlos Y. |
| Fraternal birth order (FBO) appears as a prenatal cause of 15% of homosexual males (gays) through mnemonic maternal anti-male factors. Non-right-handed men seem to be protected from homosexuality. Four hypotheses are proposed: (1) androgenic factors of non-right-handedness neutralize anti-male factors; (2) non-right-handedness and homosexuality are lethal or produce mental impairment; (3) non-right-handed male embryos are insensitive to anti-male factors; (4) mothers of non-right-handed fetuses do not produce anti-male factors. Studies of the sex ratio (SR) of older and younger siblings show: (1) a significant heterogeneity in the SR of siblings of right or non-right handed heterosexual men and women; (2) lesbians are born among siblings with high SR; (3)... |
| Tipo: Journal article |
Palavras-chave: Homosexuality; Handedness; Sex ratio; Birth order; Fetomoternal tolerance; Genetic distortions. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602010000300012 |
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| Vasconcelos,Lilian Paula; Súarez,Yzel Rondon; Lima-Junior,Sidnei Eduardo. |
| In order to describe some aspects of the population ecology of Bryconamericus stramineus in the Guiraí River basin, upper Paraná River basin, samples were taken bimonthly from October 2006 to August 2007 at seven sites in the basin. A total of 960 individuals, including 532 females, 316 males, and 112 of undetermined sex, were collected. A significant variation in the sex ratio was observed (Χ2 = 32.82; p < 0.001). Females were larger (59.7 mm) than males (58.9 mm); however, males showed a larger angular growth coefficient (b) than females. It was estimated that 50% of females were sexually mature at 36.4 mm. The highest rate of ovary development was observed in October, while in June 2007 no mature females were found. Mean fecundity was estimated at... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Length-weight relationship; Mortality; Reproductive strategy; Sex ratio. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032011000200006 |
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| Brito,Elizângela Silva de; Strussmann,Christine; Penha,Jerry Magno Ferreira. |
| Studies on population structure of freshwater turtles belonging to the family Chelidae are scarce in Brazil. Herein we describe the structure of a population of the chelid Mesoclemmys vanderhaegei in a Cerrado area in the municipality of Chapada dos Guimarães, Mato Grosso, Brazil. A total of 80 individuals were captured in five collecting sites, from January to March 2007: 42 adult females, 27 adult males, and 11 juveniles with undetermined sex. Among 80 individuals, 24% were recaptured, at least once. This is the first attempt to estimate the size of a population of Mesoclemmys vanderhaegei. Our results suggest that additional sampling efforts are needed for more accurate estimates of population structure. Nevertheless, they surely provide minimum values... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Chelidae; Neotropics; Sex ratio; Population size; Freshwater turtles. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032009000400024 |
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| Castiglioni,Daniela da Silva; Limberger,Marcio; Castro,Vanessa da Silva; Ubessi,Francieli. |
| Abstract The study of population and reproductive traits provides information about the ecological structure of natural populations. This study aimed to characterize dynamics and reproductive traits of Hyalella palmeirensis from a natural pond from southern Brazil. The amphipods were sampled monthly (August 2012 to July 2013) by a person with the aid of a hand net for 20 minutes. Ovigerous females and pre-copulatory pairs were individualized in the field. A total of 12,325 individuals were sampled, being 1,421 males, 6,983 females (including 215 ovigerous females) and 3,921 juveniles. Paired and unpaired males were significantly greater in size than females. There was a positive correlation between body size (CL) of paired males and females. Males and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fecundity; Body size; Hyalella palmeirensis; Sex ratio; Reproduction; Recruitment. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032020000200204 |
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| Biagiotto,Renan Hohendorff; Rondineli,Giulianna; Carmassi,Alberto Luciano; Braga,Francisco Manoel de Souza. |
| The aim of this work was to present the reproductive aspects of Harttia carvalhoi Miranda Ribeiro, 1939, a small loricariid whose distribution is restricted to the area of drainage basin of the Paraíba do Sul river. A total of 110 specimens of H. carvalhoi were captured. The reproductive period happens from September to February. A total spawning type was identified and fecundity rate ranged from 16 to 106 oocytes. This type of study is important, since fecundity is a specific feature and is adapted to the conditions of the life cycle, varying with growth, population density, food availability and mortality rate. We also emphasize the importance of this study, since there are no previous studies about the reproduction of this species. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Loricariinae; Sex ratio; Reproductive period; Fecundity; Brazil. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032012000400026 |
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| Vaz-dos-Santos,André Martins; Rossi-Wongtschowski,Carmen Lúcia Del Bianco; Honji,Renato Massaaki; Bannwart,Denis. |
| This study describes the reproduction of the silver John dory, Zenopsis conchifer, based on data collected before its fishery exploitation in the southwestern Atlantic, Brazil, in the early 2000s. Biological material was collected through bottom-trawl surveys in 2001 and 2002 from depths of 100 to 600 m. A total of 1,056 individuals ranging from 57 to 504 mm Ls were analyzed. A sex ratio analysis showed that males were predominant among the shorter fishes (< 240 mm Ls) and females among the longer ones (> 320 mm Ls). Between 240 mm and 319 mm Ls sex-ratio was 1:1. The silver John dory is a multiple spawner. Spawning is protracted and more intensive during August and November, when both females and males in spawning capable actively spawning and in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spawning period and area; Length at first maturation; Sex ratio; Gonadosomatic index. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032014000300120 |
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| Brook, Barry W; Northern Territory University; barry.brook@ntu.edu.au; Burgman, Mark A; University of Melbourne; m.burgman@botany.unimelb.edu.au; Frankham, Richard; Macquarie University; rfrankha@rna.bio.mq.edu.au. |
| Population viability analysis (PVA) is used in conservation biology to predict extinction probabilities for threatened species. Previous studies have revealed large differences between the predictions of PVA modeling packages, but these comparisons included a range of nonstandard factors. A standardized comparison of five PVA packages (GAPPS, INMAT, RAMAS Metapop, RAMAS Stage, and VORTEX) was conducted on six examples (two mammals, two birds, one reptile, and a hypothetical bird/mammal-like life history). The individual-based packages (GAPPS and VORTEX) predicted a consistently higher risk of extinction than their matrix-based counterparts (INMAT and the RAMAS programs). This arose as only the former considered the effect of demographic stochasticity in... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Demographic stochasticity; Extinction risk; Individual-based models; Matrix-based models; Model comparison; Parameter estimation; Population viability analysis; Sex ratio. |
| Ano: 2000 |
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| Pratissoli,Dirceu; Polanczyk,Ricardo A; Holtz,Anderson M; Dalvi,Leandro P; Silva,Alexandre F; Silva,Luciano N. |
| Biological characteristics of the egg parasitoids Trichogramma acacioi, T. atopovirilia, and T. bennetti were studied to select the one with better performance on the control of the Diamondback moth, Plutella xylostella. Parasitism rate, viability, and sex ratio were studied. Parasitism rate ranged from 1.67 to 41.33%. T. atopovirilia and T. acacioi were respectively the most and less aggressive species. The viability ranged from 6.20% for T. acacioi to 53.34% for T. atopovirilia. There were no differences on sex ratio (P < 0.05) that remained above 0,88. T. atopovirilia was the species with best performance in the laboratory when rearing on the Diamondback moth eggs. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Plutella xylostella; Biological control; Egg parasitoids; Parasitism; Sex ratio; Viability. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362008000200013 |
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| Pratissoli,Dirceu; Polanczyk,Ricardo A; Holtz,Anderson M; Dalvi,Leandro P; Silva,Alexandre F; Silva,Luciano N. |
| Biological characteristics of the egg parasitoids Trichogramma acacioi, T. atopovirilia, and T. bennetti were studied to select the one with better performance on the control of the Diamondback moth, Plutella xylostella. Parasitism rate, viability, and sex ratio were studied. Parasitism rate ranged from 1.67 to 41.33%. T. atopovirilia and T. acacioi were respectively the most and less aggressive species. The viability ranged from 6.20% for T. acacioi to 53.34% for T. atopovirilia. There were no differences on sex ratio (p<0.05) that remained above 0,88. T. atopovirilia was the species with best performance in the laboratory when rearing on the Diamondback moth eggs. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Plutella xylostella; Biological control; Egg parasitoids; Parasitism; Sex ratio; Viability. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362008000200026 |
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| Registros recuperados: 84 | |
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