INTENSITY AND SITE OF PLAGIORCHIS-ELEGANS (TREMATODA, PLAGIORCHIIDAE)INFECTIONS IN AEDES-AEGYPTI (DIPTERA, CULICIDAE) LARVAE AFFECT THE ATTRACTIVENESS OF THEIR WATERS TO OVIPOSITING, CONSPECIFIC FEMALES

A series of biological assays was conducted in the laboratory to asses s the oviposition responses of Aedes aegypti (L.) to waters that had h arbored conspecific larvae parasitized with the entomopathogenic digen ean Plagiorchis elegans (Rudolphi). Infections were of various intensi ties and locations within the bodies of 2nd, 3rd, and 4th instars. Reg ardless of instar and location of infection, repellency of the waters to ovipositing females increased with the intensity of infections of t he larvae. Similarly, waters derived from larvae with infections of th e head and thorax tended to be more repellent than waters from larvae with abdominal infections, regardless of instar and intensity of infec tion. Oviposition repellency was greatest in response to waters from 2 nd and 4th ir;stars; the mean numbers of eggs laid on these waters was approximate to 1/2 that on distilled water controls. These data sugge st that sublethal infections of A. aegypti larvae with P. elegans may reduce the recruitment of Ist instars into the preimago population.