The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

PHYSICAL AND BIOCHEMICAL INTERRELATIONSHIPS AMONG WHEAT CULTIVARS ABE, MONON, AND KNOX 62 FOR RESISTANCE TO HESSIAN FLY BIOTYPES B, C, AND D

Studies showed that the resistances of wheat cultivars, Abe to biotype C, Monon to biotype C, and Knox 62 to biotype B were stable at a high temperature of 25 C for all larval densities tested. At 25 C almost 100% of Abe seedlings were infested by biotype B, whereas only about 50% of Abe seedling were infested by biotype D. Secondary plant compounds which may occur in wheat were tested topically for toxicity to Hessian fly red larvae of biotypes B and C. The only 2 compounds that caused detrimental effects to both biotypes were vanillin (a phenolic compound) and methoxy-parabenzoate (a fungicide). Both had relatively low toxicity. Wheat stem agglutinin (WSA) found in stem is a protein with apparent high molecular weight. This agglutinin is distinct from wheat germ agglutinin (WGA), for its ability to agglutinate mammalian erythrocytes was not blocked by N-acetylglucosamine and its high molecular weight appeared to be much higher. Topical applications of wheat stem extracts containing the agglutinin from Abe, Monon, and Knox 62 cultivars on first instar Hessian fly larvae were not toxic to both virulent and avirulent larvae. This suggested the necessity of developing a sensitive feeding bioassay in order to evaluate the roles of wheat chemicals in plant-Hessian fly interactions. A candidate biochemical model of the gene-for-gene interrelationship for Abe, Monon, and Knox 62 cultivar vs Hessian fly biotype B, C and D was developed which suggests the possibility that a biochemical recognition between Abe cultivar to biotype B, C, and D is sensitive to an elevated temperature of 25 C. The model also shows the possibility that the resistances of Abe cultivar to biotype C and Monon cultivar to biotype C may possess the same biochemical mechanism of resistance since both have the same biochemical recognition