The Impact of Selective Oviposition and Infection with Plagiorchis elegans on Aedes aegypti Pre-Imago Population Dynamics at Optimal Food Availability

Abstract

Progressive changes in the attraction of waters harboring pre-imago populations of Aedes aegypti exposed to different levels of the entomopathogenic digenean Plagiorchis elegans to ovipositing conspecific females were assessed under conditions of optimal food availability. The impact of ovipositional preference and parasitic infection on population structure and development was investigated. Probabilities that larvae progress from one stage to the next or die within 24 h were calculated for all life stages. Exposure to P. elegans cercariae did not significantly affect the attractiveness of larval-holding waters. Ovipositional preference increased significantly with growing biomass of the larval population, with the event of pupation and, in some cases, with late instar mortality. Exposure to various levels of the parasite significantly increased mortality of all instars, but most of the damage caused by the parasite occurred in the form of increased pupal mortality and decreased adult emergence. Exposure to the parasite significantly reduced the number of adults produced yet did not impair larval development. Thus, larval recruitment into environments containing P. elegans remains high, the structure of larval populations remains relatively normal, but few adults are produced.