A Rapid Assessment of Larval Habitats of Mosquitoes (Diptera: Culicidae) in Aqqala County of Golestan Province, Northeastern Iran, Following the 2019 Flood.

BACKGROUND

Mosquitoes (Diptera: Culicidae) are the most important arthropods in public health. Larval habitat features play an important role in their selection by female mosquitoes for oviposition. The purpose of this study was to determine the oviposition sites of mosquitoes in Aqqala County of Golestan Province following the flood of 2019.

METHODS

Two categories of larval habitats were defined: those that naturally occurred and those that were a result of flooding. Samples were collected using dippers with a 350 ml capacity. The collected larvae were preserved in lactophenol solution. Microscope slides were prepared using Berlese medium. The specimens were morphologically identified. Larval habitat characteristics were recorded according to the habitat situation (permanent/temporary, running/stagnant), vegetation situation, sunlight situation, substrate type, water situation (turbid/clear) and habitat type (natural/artificial).

RESULTS

In total, 774 third- and fourth-instar mosquito larvae were collected from different larval habitats not affected by the flood, including seven species representing four genera. Culex pusillus was the dominant species (41.2%). The larvae of Aedes caspius, Cx. pipiens, Cx. theileri, Culiseta longiareolata and Uranotaenia unguiculata were collected only from artificial habitats, 96.9% of Cx. tritaeniorhynchus larvae from artificial habitats and 78.7% of Cx. pusillus larvae from natural habitats. No larvae were collected from the larval habitats affected by the flood.

CONCLUSION

Field observations suggested that the flushing of natural larval habitats may cause such a decrease in larval population in the habitats affected by the flood. The presence of the larvivorous fish Gambusia holbrooki may also be taken into consideration.