Effects of Atlantic Ocean Water on hatchability and pre-imaginal development of Aedes aegypti (L)

Abstract

Aedes aegypti is an efficient transmitter of various deadly and debilitating diseases such as yellow fever, dengue and Zika virus in various parts of the world. In this study, we evaluated the effects of various concentrations of Atlantic ocean water on hatchability and pre-imaginal development of Ae. aegypti mosquito. The Atlantic Ocean Water was diluted with distilled water into five concentrations, namely 0.5%, 1.0%, 1.5%, 2.0% and 2.5% (V/V). Twenty eggs obtained from F_o generation of laboratory-bred Ae. aegypti were exposed to the five concentrations of Atlantic ocean water while distilled water was used as control. The number of larval, pupal and adult emergence were monitored. The eggs laid by F₁ generation from various concentrations were re-exposed to the concentrations to monitor F₂ generations. The bioassays were replicated thrice. The results showed that 73.3% of the eggs hatched in distilled water which was significantly higher (p<0.05) than diluted concentrations of Atlantic Ocean Water whose hatchability ranges between 35%- 46.6%. Though, the pupal and adult emergence was higher in distilled water as compared with test concentrations, the differences were not statistically significant (p>0.05). The duration of emergence was significantly shorter in distilled water as compared with test concentrations (p<0.05). In F₂ generation, while 10.0% and 1.66% of the larvae in 0.5% and 1.0% concentrations developed into pupae respectively, none of the larvae in concentration between 1.5%-2.5% developed into pupae and adults. The results of the present study showed that salinity has both direct and indirect effects on the egg hatchability and preimaginal development of generations of local species of Ae. aegypti. This could be explored in the global efforts of formulating effective strategies to exterminate insect-vectors of medical and veterinary importance.

Keywords: Matchability; Aedes aegpti; ocean water.