Caractérisation de culex pipiens (Linnaeus, 1758) et culiseta longiareolata (Macquart, 1838) et toxicité des extraits des plantes sur leurs larves.

Abstract

This study focused on two of the most dominant mosquito species in Algeria: Culex pipiens s.l. and Culiseta longiareolata. Both of these pathogen vectors present significant public health challenges on a global scale but have been relatively understudied in Algeria. In this research, we first analyzed the ecological differentiation between Culex pipiens pipiens and Culex pipiens molestus, two members of the Cx. pipiens complex, known for their distinct behavioral and physiological characteristics. traits, such as autogeny rates, were also studied. Nine populations of Cx. pipiens s.l. were sampled from various urban and rural habitats in the Setif region, distributed across aboveground and underground breeding sites. The molecular identification of larvae, carried out using the CQ11 microsatellite locus, revealed that the three biotypes (Cx. p. pipiens, Cx. p. molestus, and their hybrids) coexisted in sympatry in both and underground breeding sites, with the molestus form being dominant, followed by hybrids and the pipiens form. Cx. p. pipiens preferred rural habitats and surface breeding sites and was characterized by an anautogenous behavior. In contrast, Cx. p. molestus and hybrids showed no specific preference for a particular type of habitat or breeding site. However, these two forms exhibited a notable capacity to be autogenous, particularly in underground breeding sites. Furthermore, the analyses confirm that autogeny is strongly correlated with underground breeding sites. Simultaneously, a molecular analysis based on the amplification of the COI gene, followed by sequencing of Cs. longiareolata specimens collected from four aboveground breeding sites, revealed the presence of five haplotypes, suggesting a high degree of similarity within the studied population. Additionally, it displayed no autogenous behavior. The second part of this research focused on the chemical characterization of essential oils from three plants: Cymbopogon citratus, Saccocalyx satureioides, and Pimpinella anisum, as well as on the evaluation of their larvicidal activity against the larvae of the two species, Cx. pipiens s.l. and Cs. longiareolata. The essential oils were extracted by hydrodistillation of dried aerial parts, with yields of 0.9% for C. citratus, 2% for S. satureioides, and 4% for P. anisum. The oils were then analyzed using gas chromatography-mass spectrometry (GC-MS), revealing 48 compounds in C.