Relationship between the L1014F mutation in the kdr gene and the endophagic and exophagic behaviors of Anopheles coluzzii and Anopheles gambiae in Benin

The increasing resistance exhibited by Anopheles gambiae and Anopheles coluzzii to insecticides represents a major challenge for malaria vector control strategies. This study aimed to investigate the relationship between the L1014F mutation in the kdr gene, the endophagic, and exophagic behaviors of Anopheles coluzzii and Anopheles gambiae in Benin.

The study was conducted in Kandi, Gogounou, Djougou, Copargo, and Porto-Novo, where mosquitoes were collected through human landing catches performed both indoors and outdoors. After morphological identification of the collected specimens, female Anopheles mosquitoes were used to determine endophagic and exophagic biting rates. Each specimen was stored on silica gel in 1.5-mL plastic tubes (Eppendorf) containing cotton at − 20 °C. The abdominal portions were used for DNA extraction. The polymerase chain reaction (PCR) was performed to detect kdr gene mutation, and to identify sibling species within the Anopheles gambiae sensu stricto complex (Anopheles gambiae and Anopheles coluzzii).

The findings indicate that the abundance of Anopheles gambiae was significantly higher (P < 0.05) than that of Anopheles coluzzii in the municipalities of Djougou and Copargo. Conversely, in Porto-Novo and Kandi, Anopheles coluzzii populations were significantly more abundant (P < 0.05) than Anopheles gambiae. The presence of the L1014F mutation in the kdr gene was associated with a stronger tendency toward exophagic behavior in Anopheles coluzzii. In contrast, resistant homozygous individuals (L1014F/L1014F) of Anopheles gambiae tended to bite indoors rather than outdoors.

The observed relationships between kdr allele frequency and the exophagic and endophagic behaviors of Anopheles gambiae and Anopheles coluzzii provide important insights that may support the development of additional vector control strategies targeting exophagic malaria vectors.