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| Felix,Mónica M. L.; Petriella,Ana M.. |
| The molt cycle of the natural population of Palaemonetes argentinus Nobili, 1901 from Los Padres Lagoon, Buenos Aires, Argentina, was studied in relation to age, sex, and environmental factors. A total of 1645 individuals (740 females, 539 males, and 366 juveniles) were collected and analyzed between December 1995 and December 1996. The results indicate that the sex ratio (males:females) remains around 1:1.4 throughout most of the year. The reproductive period extends from September until February (spring and summer), with maximum sexual activity in October and November. Two cohorts originated in the spring and in the summer were differentiated. Ovigerous females arrest their molt cycle during the intermolt period to restart it after oviposition. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Palaemonetes; Decapoda; Palaemonidae; Molt cycle; Ovarian maturation. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212003000400007 |
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| García-Dávila,Carmen Rosa; Magalhães,Célio; Guerrero,José Camilo Hurtado. |
| Morphometric variability among shrimp populations of the genus Palaemonetes Heller, 1869 from seven lakes (Huanayo and Urcococha, in Peru; Amanã, Mamirauá, Camaleão, Cristalino e Iruçanga, in Brasil) in the Amazon Basin, presumably belonging to Palaemonetes carteri Gordon, 1935 and Palaemonetes ivonicus Holthuis, 1950, were studied. The morphometric studies were carried out from the ratios obtained from the morphometric characters. Multivariated analysis (Principal Components Analysis-PCA, Discriminant Function Analysis and Cluster Analysis) were applied over the ratios. Intra- and interpopulation variations of the rostrum teeth, and the number of spines in the male appendix, were analyzed through descriptive statistics and bivariate analysis (Spearman... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Palaemonetes; Morphometry; Amazon Basin; Sibling species; Freshwater shrimp. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212005000300013 |
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| Giri,Federico; Collins,Pablo. |
| The predator-prey relationship of Palaemonetes argentinus Nobili, 1901 and Culex pipiens s.l. larvae was studied under laboratory conditions. The prawns were separated in two groups, isolated and grouped ones. Mosquitoe larvae were offered to prawns in two forms, limited and unlimited offer to both groups. In the first analysis, values of predation did not differ significantly between males and females of P. argentinus. Predation in 24 h was 14,9 ± 4,2 larvae/prawn. A reduction of predation was observed with unlimited offer for the same hour, during all the experiment. Predation with unlimited offer was higher on the first day than on the second, but returned to high values on the third day, for both groups. In the grouped experiment, predation with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Palaemonidae; Palaemonetes; Culex; Biological control. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212003000300002 |
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| Merchant, Henry C.; Khan, Ritindra N.; Knowlton, Robert E.. |
| Effects of three different macrophytic covers and the presence of alternative prey on survival of grass shrimp (Palaemonetes pugio and P. vulgaris) subjected to predation by killifish (Fundulus heteroclitus) were studied in the laboratory. Overall, survival of P. vulgaris was significantly greater (82%) than that of P. pugio (70%). This difference in survival was attributed to the greater tendency of P. pugio to swim outside the covers, making it more vulnerable to predation. Both prey species responded similarly to the different cover conditions. Survival without cover (gravel substrate) was 48%. In cover provided by a plastic plant made to resemble Ambulia, 75% of the starting population survived. In cover furnished by field-collected specimens of the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Palaemonetes; Predation; Macrophytic cover; Survivorship. |
| Ano: 2001 |
URL: http://www.repository.naturalis.nl/record/534315 |
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