RESUMO
We investigated the cellular basis of two extensive, continuous, latitudinal, genetic, body size clines of Drosophila melanogaster by measuring wing area and cell size in the wing blade of adult flies reared under standard, laboratory conditions. We report that the contribution of cell size to an Australian cline is much smaller than that to a South American cline. The data suggest that neither cell size nor cell number were the targets of selection, but rather wing area itself, or a trait closely related to it. We hypothesize that the differences between the continents were caused by differences in the initial pattern of genetic variation for the cell traits and/or by the direction of selection on the source populations of the clines. Despite large differences between continents in the cellular basis of the latitudinal variation, multiple regression analysis, using the individual variation within populations, showed that the relationship between cell size and cell number was changed with latitude in the same way in the two clines. The relative contribution of cell number to wing area variation increased with latitude, probably because of compensatory interactions with cell size as a consequence of the latitudinal increase in cell number. Our findings are discussed in relation to the cellular basis of evolutionary change in laboratory thermal selection lines and natural populations along latitudinal clines.
Assuntos
Drosophila melanogaster/anatomia & histologia , Drosophila melanogaster/genética , Asas de Animais/anatomia & histologia , Análise de Variância , Animais , Austrália , Chile , Equador , Feminino , Variação Genética , Genética Populacional , Modelos Lineares , Masculino , Modelos Genéticos , Asas de Animais/citologiaRESUMO
Results of a recent survey of the 3 species of Anopheles mosquitoes, Anopheles (Nyssorhynchus) aquasalis, Anopheles (Nyssorhynchus) argyritarsis, and Anopheles (Anopheles) pseudopunctipennis, on the island of Grenada are contrasted with the only other published survey of these species on Grenada, which was published in 1938. Results suggest that a significant change in the abundance and distribution of each species has occurred over this period. Physical characteristics of the aquatic habitats for each species are described and compared.
Assuntos
Anopheles , Animais , Feminino , Geografia , Oviposição , Dinâmica Populacional , Índias OcidentaisRESUMO
Sera from 1,206 livestock animals and chickens on Grenada and Trinidad were tested for leptospiral antibodies by the microscopic agglutination test. 376 of the sera were positive (25% of those tested on Grenada and 44% on Trinidad). The positive sera were obtained from 25% of 324 cattle, 35% of 130 pigs, 35% of 146 sheep, 25% of 44 goats and 11% of 175 chickens on Grenada; and 92% of 26 cattle, 53% of 122 pigs, 76% of 87 horses and donkeys and 11% of 144 chickens on Trinidad. Eight sera from ducks and geese on Trinidad were tested and found to be negative. The serogroups most commonly found to react with the sera of the Grenadian animals were Autumnalis, Icterohaemorrhagiae, Hebdomadis and the related serogroups Sejroe and Mini, and Pyrogenes; in the Trinidadian animals they were Icterohaemorrhagiae, Autumnalis, Hebdomadis and its related serogroups, and Panama. Strains of serogroup Pomona do not appear to have become established as livestock pathogens on the islands.
Assuntos
Anticorpos Antibacterianos/análise , Leptospirose/veterinária , Testes de Aglutinação , Animais , Bovinos , Doenças dos Bovinos/imunologia , Galinhas , Cabras , Doenças dos Cavalos/imunologia , Cavalos , Leptospirose/imunologia , Doenças das Aves Domésticas/imunologia , Ovinos , Doenças dos Ovinos/imunologia , Suínos , Doenças dos Suínos/imunologia , Trinidad e Tobago , Índias OcidentaisRESUMO
Serum samples from 894 wild animals (representing 31 species) from Trinidad and Grenada were examined by the microscopic agglutination test for leptospiral antibodies; 198 were positive. These included 39 bats, 88 mongooses, six opossums, 10 peridomestic rodents, 15 forest rodents, 10 lizards, and 30 toads. Thirteen pathogenic serogroups were involved. Thirty-nine Leptospira isolates were reported from mongooses, opossums, rodents and toads.
Assuntos
Grupos de População Animal , Animais Selvagens , Reservatórios de Doenças/veterinária , Leptospirose/veterinária , Aglutininas/análise , Animais , Anticorpos Antibacterianos/análise , Leptospira/imunologia , Leptospira/isolamento & purificação , Leptospirose/microbiologia , Especificidade da Espécie , Trinidad e Tobago , Índias OcidentaisRESUMO
All known isolates of Leptospira interrogans obtained in Trinidad, Grenada and St. Vincent up to the end of 1979 are listed. There were 80 from Trinidad, 20 from Grenada and 2 from St. Vincent, representing at least 20 serotypes from 11 or more serogroups. Six of the serotypes were first reported from Trinidad. The leptospires were isolated from man, domestic animals and wildlife species.