Influence of larval density or food variation on the geometry of the wing of Aedes (Stegomyia) aegypti
Source: Tropical Medicine & International Health, Volume 12, Number 11, November 2007 , pp. 1354-1360(7)
Abstract:Summary Background and Method Variation in wing length among natural populations of Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) is associated with different vectorial capacities. Geometric morphometrics allowed us to use a more powerful estimator of wing size (`centroid size'), as well as to visualize the variation of wing shape, to describe the effects of density or food variation at larval stage on 20 anatomical landmarks of the wing of A. aegypti. Results Almost perfect correlations between (centroid) size and larval density or size and larval food were observed in both sexes: a negative correlation with increasing density and a positive one with increasing amount of food. The allometric component of shape change was always highly significant, with stronger contribution of size to shape under food effects. Within each experiment, either food or density effects, and excluding extreme conditions, allometric trends were similar among replicates and sexes. However, they differed between the two experiments, suggesting different axes of wing growth. Conclusion Aedes aegypti size is highly sensible to food concentration or population density acting at larval stages. As larger individuals could be better vectors, and because of the stronger effect of food concentration on size, vector control activities should pay more attention in eliminating containers with rich organic matter. Furthermore, as a simple reduction in larval density could significantly increase the size of the survivors, turning them into potentially better vectors, the control activities should try to obtain a complete elimination of the domestic populations.
Document Type: Research article
Affiliations: 1: Center for Vaccine Development, Institute of Science and Technology for Research and Development, Mahidol University, Salaya, Nakhonpathom, Thailand 2: Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand 3: Department of Biostatistics, Faculty of Public Health, Mahidol University, Bangkok, Thailand 4: Institut de Recherche pour le Développement, Montpellier, France 5: Institut de Recherche pour le Développement, Center of Excellence for Vectors and Vector borne Diseases, Mahidol University, Bangkok, Thailand
Publication date: 2007-11-01