Effects of oil from Bonny Light Crude on Adult Winglength, Fluctuating Asymmetry, Body size and Nutritional reserve in Anopheles gambiae (s.l.)

Abstract

The study was carried out to determine the influence of crude-oil contaminated mosquito larval habitat on the wing length, fluctuating asymmetry, adult body size and nutritional reserve of Anopheles gambiae (s.l.) The oil was obtained by distillation of bonny light crude obtained from Port-Harcourt, Nigeria using appropriate standard methods. Results obtained showed that the left and right wing lengths varied significantly across concentrations in the male population ranging from 3.25±0.42 (0.5 mlL^-1) to 3.83±0.41mm (0.1 mlL^-1) and 3.33±0.26mm (1.00 mlL^-1) to 3.75±0.27mm (0.1 mlL^-1 and 0.25 mlL^-1), respectively. The left and right wing lengths of the female mosquitoes, however, did not vary significantly; ranging from 3.53±0.26mm (0.5 mlL^-1) to 3.83±0.26 mm (0.1 mlL^-1) and 3.58±0.20mm (0.75 mlL^-1) to 3.67±0.41mm (1.00 mlL^-1), respectively. The female population showed varying fluctuating asymmetry across concentrations; these were statistically different ranging from 0.16±0.25mm (in Control) to 0.30±0.26mm (in 0.50 mlL^-1). The mosquitoes varied significantly in body sizes across concentrations. Male mosquito body size ranged from 37.58±8.20mm (in 1.00mlL^-1) to 55.08±10.41 mm (in 0.1mlL^-1), while female body size ranged from 37.72±4.19 (in 0.5mlL^-1) to 54.85±8.05 mm (in 0.1mlL^-1). The teneral reserve showed a consistent trend of decrease along the concentration as it increases. The glycogen reserve was significantly low (5.44±0.41 µg/mL) in the 1.0mlL^-1 population and highest (8.91±0.23 µg/mL) in the control population, though the glycogen in the control was not significantly different from those of 0.1mlL^-1, 0.25mlL^-1 and 0.5mlL^-1 but was significantly different from 0.75mlL^-1 (7.10±0.24 µg/mL). The result of this study gives a better understanding of the interaction between crude oil contamination and vectorial fitness attributes of Anopheles gambiae to serve as prelude for effective vector control in such area with crude oil spillage.