The Significance of Leaf Detritus to Mosquito (Diptera: Culicidae) Productivity from Treeholes

Abstract

Relationship between leaf detritus and productivity of Aedes triseriatus (Say) from beech treeholes was studied. Leaf mass in treeholes was positively correlated with area of treehole entrance. Leaf packs in treeholes lost ca. 69% of their mass during the summer season. In the first experiment lasting 18 wk, there was no difference in number of mosquitoes emerged, average individual mass, development time, or total mass of males or females from treeholes without leaves or treeholes with leaves. Individual mosquitoes were not generally smaller in size with increasing date of emergence. Inorganic nutrient (nitrite, nitrate, phosphate, sulfate, and ammonia) and dissolved organic carbon concentrations in treehole water varied seasonally with rainfall and other factors but did not differ between groups of treeholes with or without leaves. Bacterial concentrations in treehole water were higher in nine treeholes before than after a rainfall, ranging overall from 1.92 × 106 to 54.70 × 106 cells per ml. In a second experiment lasting about seven weeks, there was no difference in larval mass between treeholes with leaves and those without leaves. Behavioral observations showed that larvae filtered treehole water and browsed tree bark and leaves. Overall, our results suggest that leaves are probably only one of many food resources for mosquito larvae in treeholes; bacteria in treehole water may be more important as food than microbiota attached to leaves.