Studies on the fitness characteristics of Mel- and AlbB-introgressed (Pud) lines in comparison with Mel- and AlbB-transinfected (Aus) and wild-type (Pud) lines.

, an intracellular maternally transmitted endosymbiont, has been shown to interfere with the replication of dengue virus in mosquitoes. The -transinfected has been currently released in many countries to test its effectiveness in preventing the transmission of dengue virus. ICMR-Vector Control Research Centre in collaboration with World Mosquito Program Monash University, Australia, has generated two new -introgressed Puducherry (Pud) lines backcrossing females of Australian (Aus) strains, infected with Mel and AlbB with wild-type Puducherry (Pud) males. infections are known to induce a fitness cost and confer benefit on the host mosquito populations that will influence spread of the into native wild mosquito populations during the field release. Hence, the induced fitness cost or benefit/advantage in the two newly generated (Pud) lines was assessed in the laboratory in comparison with the wild-type (Pud) strain. In addition, maternal transmission (MT) efficiency, induced cytoplasmic incompatibility (CI), and insecticide resistance status of the two (Pud) lines were determined to assess the likely frequency of Mel and AlbB infections in the native wild population after field invasion. The study shows that Mel and AlbB infections did not induce any fitness cost on the two newly generated (Pud) lines. Rather, in terms of wing length, fecundity, egg hatch rate, and adult survival, the introgression conferred fitness benefits on the (Pud) lines compared to uninfected free wild population. Mel and AlbB exhibited a high maternal transmission (99-100%) and induced nearly complete (98-100%) cytoplasmic incompatibility. Both the (Pud) lines were resistant to deltamethrin, malathion, DDT, and temephos, and the level of resistance was almost the same between the two lines as in the wild type. Overall, the stable association of Mel and AlbB established with and the reproductive advantages of the (Pud) lines encourage a pilot release in the field for population replacement potential.