Malaria vectors in the Brazilian Amazon: Anopheles of the subgenus Nyssorhynchus

Various species of Anopheles (Nyssorhynchus) were studied in the Amazon with the objective of determining their importance as malaria vectors. Of the 33 known Anopheles species occurring in the Amazon, only 9 were found to be infected with Plasmodium. The different species of this subgenus varied both in diversity and density in the collection areas. The populations showed a tendency towards lower density and diversity in virgin forest than in areas modified by human intervention. The principal vector, An. darlingi, is anthropophilic with a continuous activity cycle lasting the entire night but peaking at sunset and sunrise. These species (Nyssorhynchus) are peridomiciliary, entering houses to feed on blood and immediately leaving to settle on nearby vegetation. Anopheles nuneztovari proved to be zoophilic, crepuscular and peridomiciliary. These habits may change depending on a series of external factors, especially those related to human activity. There is a possibility that sibling species exist in the study area and they are being studied with reference to An. darlingi. An. albitarsis and An. nuneztovari. The present results do not suggest the existence of subpopulations of An. darlingi in the Brazilian Amazon

Genetic divergence in mitochondrial DNA of Anopheles nuneztovari (Diptera: Culicidae) from Brazil and Colombia

In the present study, we have examined the variability in Anopheles nuneztovari mitochondrial DNA of three populations from the Brazilian Amazon and one from western Colombia (Sitronela), using four restriction endonucleases (BclI, ClaI, HindIII, SstI). The haplotype diversity (h) was slightly elevated in all populations (0.5000 to 0.6765), whereas the nucleotide diversity (π) was lower in the Sitronela population (0.0029) and higher in populations from the Brazilian Amazon (0.0056 to 0.0098). The degree of sequence divergence (δ) estimated within the Brazilian Amazon and that in Sitronela (0.0329 to 0.0371) suggests that these geographic populations of A. nuneztovari may eventually constitute separate species. The low sequence divergence values among the three Brazilian Amazon populations (0.0012 to 0.0031) indicate that these populations are genetically similar. These results are consistent with those recently reported for allozymes of these same populations

Environment-enzyme polymorphism relationships in two Hawaiian Drosophila species

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.Seven polymorphic enzyme-gene loci in Drosophila mimica and five such loci in D. engyochracea were investigated in a time-dependent study. Heterozygosity levels were stressed and relationships determined between heterozygosity and different weather variables and between allele frequencies and different weather parameters. Coordinated shifts in heterozygosity level were noted for different loci in each species. In D. mimica, significant correlations between rainfall and specific allele frequencies at the IDH-1, PGM-1 and EST-2 loci were found. Such a correlation was also found for D. engyochracea at the PGM-1 locus. These findings are discussed with respect to the metabolic roles of these enzymes and their value for predicting associated changes in the genetic architecture of the gene pools they reside in. These activities are consistent with Darwinian theory and not with theories which invoke neutrality.Research was supported by NSF grants GB-23230, GM-27586, and GB-29288

Techniques for electrophoresis of Hawaiian Drosophila

Reports were scanned in black and white at a resolution of 600 dots per inch and were converted to text using Adobe Paper Capture Plug-in.In this report, we have described the equipment, techniques and chemical solutions necessary to do electrophoresis on Hawaiian Drosophila and some other organisms. Such techniques are useful in analyzing genetic relationships and population structure