EFFECT OF LEAF-LITTER AND DENSITY ON FITNESS AND POPULATION PERFORMANCE OF THE HOLE MOSQUITO AEDES TRISERIATUS

1. We tested the effects of food, in the form of leaf litter, and dens ity on population growth and fitness correlates of the tree hole mosqu ito Aedes triseriatus. Our field experiment used a 2 x 2 randomized bl ock design, with three holes as blocks. In cages within three holes, w e manipulated densities of Aedes triseriatus larvae, and presence of l eaf litter. Our laboratory experiment used a 2 x 3 factorial design in which we also manipulated densities of larvae and availability of lea f litter within similar cages (inside, outside, or absent). For both e xperiments we determined effects on survival, days to and mass at eclo sion of both sexes, and a composite index of population performance la mbda', that estimates finite rate of increase. 2. In the field experim ent, we found significant and large effects of leaf litter and of dens ity on the performance of A. triseriatus. The effect of density did no t depend on leaf litter availability. We documented significant variat ion among tree holes for most correlates of fitness. Often, the effect s of treatments varied significantly depending on the tree hole tested . 3. In the laboratory experiment we found significant effects of dens ity and litter, and that direct browsing on leaf litter is necessary f or the effect of litter on performance of A. triseriatus. In the labor atory, the negative effect of increased density was dependent on leaf litter availability. 4. Our results demonstrate that leaf litter has i mportant effects on population performance of tree hole mosquitoes in natural tree holes, Direct browsing on the surface of leaf litter is t he most likely mechanism by which litter enhances population growth. T he impact of litter on populations varies among tree holes.