Romanomermis culicivorax parasitism and the development, growth, and feeding rates of two mosquito species

Abstract

The dry weight, development, and feeding rates of Culex pipiens and Toxorhynchites amboinensis larvae infected with the nematode, Romanomermis culicivorax, were measured and gross conversion efficiences were calculated. The weight of C. pipiens larvae infected at two different inoculum levels did not differ significantly from controls until day 6 postinfection (PI). Infected larvae of T. amboinensis were significantly lighter than controls at days 2, 4, and 6 PI. The rate of larval mosquito development was slowed after day 3 in parasitized individuals of both mosquito species. Infection significantly retarded the interval feeding rate of the filter-feeding C. pipiens throughout development. Infected T. amboinensis larvae consumed significantly fewer prey larvae of C. pipiens than controls. Calculation of gross conversion efficiency (GCE) showed that lightly infected C. pipiens larvae had an elevated GCE early in the infection but were less efficient relative to controls after 4 days PI. Lightly parasitized T. amboinensis had a lower total GCE than controls.