Hilal Bedir

Aims: Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) is a highly invasive vector responsible for the transmission of several arboviruses worldwide. This study aimed to evaluate the chemical composition, larvicidal activity, and oviposition deterrent effects of EOs extracted from Laurus nobilis L. (Lauraceae), Cupressus macrocarpa Hartw. (Cupressaceae), and Eucalyptus globulus Labill. (Myrtaceae) harvested from the Eastern Black Sea region of Türkiye against Ae. albopictus.Materials and Methods: Essential oils were obtained by hydrodistillation and their chemical constituents were identified using GC-MS. Larvicidal bioassays were conducted to determine the median lethal concentrations LC50, and oviposition preference was evaluated across multiple concentrations to calculate the Oviposition Deterrence Index (ODI).Results: GC-MS analysis revealed that the major constituents were p-cymene (%31.81) and eucalyptol (%15.88) for L. nobilis, sabinene (%27.25) and terpinen-4-ol (%25.01) for C. macrocarpa, and eucalyptol (%39.09) for E. globulus. In larvicidal assays, L. nobilis exhibited the highest toxicity with an LC50 of 53.19 ppm, followed by C. macrocarpa (58.42 ppm) and E. globulus (62.15 ppm). Furthermore, all EOs demonstrated exceptional oviposition deterrence at the highest surface concentration (1.2738 µL/cm²), with ODI values ranging from -0.95 to -1.00. While L. nobilis maintained consistent deterrence at lower doses, C. macrocarpa showed a biphasic response, acting as a slight attractant at 14.9 ppm before becoming a potent deterrent at higher concentrations.Discussion: Our findings suggest that EOs from the Eastern Black Sea flora, particularly L. nobilis, possess significant potential as eco-friendly larvicides and behavioral modifiers for the management of Ae. albopictus populations.

Mosquitoes (Diptera: Culicidae) are among the most important vectors transmitting medically significant pathogens and parasites to humans and animals. This study aimed to determine the species composition, distribution, and relative abundance of mosquito fauna in the Eastern and Middle Black Sea regions of Türkiye between 2014 and 2022. A total of 46081 adult specimens were collected from 1700 sampling points in 513 localities across 14 provinces using larval dipping, light traps, BG-Sentinel traps, and human landing catches. Morphological identification revealed 31 mosquito species belonging to six genera: Aedes, Anopheles, Culex, Culiseta, Orthopodomyia, and Uranotaenia. Aedes albopictus was the most abundant species (40.5%), followed by Culex pipiens s.l. (37.3%) and Anopheles maculipennis s.l. (5.75%). The highest species richness was observed in Rize, Artvin, and Samsun, while Ordu and Amasya showed the lowest diversity indices. The widespread occurrence of the invasive Aedes albopictus and its rapid expansion across the region highlights the increasing risk of arboviral transmission, particularly for West Nile virus, dengue, and chikungunya. Climatic factors, vegetation types, land use, and vertebrate host availability appeared to influence spatial distribution and diversity patterns. The findings underline the necessity for continuous entomological surveillance and vector control strategies to mitigate potential mosquito-borne disease risks in this ecologically sensitive region.

Aedes aegypti (Linnaeus 1762) is a significant public health concern in both its native and invaded regions because of the transmission of arboviruses. Target-site mutations in the voltage-gated sodium channel (vgsc) gene, commonly referred to as knockdown resistance (kdr), represent the most extensively studied mechanism underlying pyrethroid resistance. Therefore, we aimed to assess possible pyrethroid and organochlorine resistance levels, knockdown resistance, and mutation types known to contribute to the resistance profile in the Black Sea region of Türkiye in 2020. Bioassay results showed that all field populations, as well as the Bora Bora laboratory strain, were susceptible and predominantly carried wild-type genotypes. For kdr, all samples were wild type for the V410L, L982W, S989P, I1011V/M, L1014F, V1016I/G, and T1520I mutations. The mutant allele was detected in only one specimen in the Pazar population, where it was found in a homozygous state at position F1534C from ten specimens. Novel mutations in the vgsc gene region, with unknown implications for resistance, were determined at positions A1498T, R1599C, P1611L, and P1615S in the studied populations. Two different intron types were detected in the kdr gene (in domain 2) between nucleotide positions 3111 and 3228 and within an intron region (coded as type-1 and type-2). These findings indicate that, Ae. aegypti populations in the Eastern Black Sea region remain susceptible to pyrethroid and organochlorine insecticides. Genetic analyses indicate that these populations likely originated from Asia, with evidence of two distinct lineages. Notably, this study represents the first molecular and phenotypic assessment of insecticide resistance in Ae. aegypti populations conducted in Türkiye.