Fitness traits and genetic characterization of a new laboratory colony of Anopheles funestus established in Ifakara, Tanzania

Abstract Background Anopheles funestus , a major vector of malaria in Africa, has proven difficult to colonize in laboratory settings, impeding research on its biology and control. After several attempts, our team recently succeeded in colonizing a strain of An. funestus from Tanzania (FUTAZ). The objective of this study was to analyze the key fitness and genotypic characteristics of these mosquitoes during multiple filial generations of laboratory adaptation and compare them to wild An. funestus from Tanzania and a pre-existing colony of An. funestus from Mozambique (FUMOZ). Methods Measures of mating success, body size, fecundity, and insecticide resistance were compared between the newly established FUTAZ colonies, the long-established FUMOZ colonies, and a colony of Anopheles arabiensis maintained in the same laboratory. The maternal lineages of the An. funestus mosquitoes were investigated through a hydrolysis probe analysis of their mitochondrial DNA to identify distinct clades. Other intragenomic variations were examined by D3-RFLP genotyping of 28S ribosomal DNA. These molecular markers were used to compare the FUTAZ colonies, FUMOZ colonies in Tanzania (TZ) and South African (SA) laboratories, and the wild-collected Tanzanian An. funestu s. Results The mating success and body size of FUTAZ females declined significantly from filial generations F1 to F6 relative to the founder population (F0) then increased from F7 onwards, eventually matching FUMOZ by F9. Fecundity was similar across all colonies tested. However, it took significantly longer for 50% of the females in the FUTAZ and FUMOZ colonies (> 10 days) to mate compared to females in the An. arabiensis colony (~ 5 days). Resistance appeared to be lost during colonization, but this varied with insecticide classes. Majority of FUTAZ mosquitoes, and the wild-caught Tanzanian An. funestus belonged to Clade I (80.4–89.4%) and RFLP type “Y” (90.5–91.4%), while FUMOZ colonies in TZ and SA were mostly Clade II (65.5–88.5%) and RFLP type “MW” (90.5–91.5%). Conclusions This study demonstrates that certain fitness traits of An. funestus , notably mating success and body size, declined during the initial phases of laboratory colonization but recovered as the population adapted to laboratory conditions. Having large founder populations is critical to survive these early-generation bottlenecks. Clade-specific and RFLP genotyping confirmed FUTAZ colony as genetically representative of wild-caught Tanzanian An. funestus . This newly established colony constitutes a valuable and reliable resource for malaria vector research.