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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.

Callosobruchus maculatus is one of the most important pests of cowpea in storage causing severe economic damage to the grain. This study investigated the efficacies of three plant materials (Azadirachta indica, Calotropis procera and Chromolaena odorata) leaves against the cowpea weevil. Concentrations of 0.1, 0.25 and 0.5g of the plant powders were used on 10g of grains with 10 adult weevils in each and a Control (untreated) in triplicates. The results showed significant (P< 0.05) negatively effects of the plant materials on the survival of C. maculatus at the highest concentration. In all trails, mean daily mortality in adult C. maculatus were significantly(p<0.05) increased. All plant powder type were effective but concentration-dependent, with C. procera recording significantly (P < 0.05) higher mortality at the various concentrations while C. odorata, elicited the least mean daily mortality. The lowest LD50 (0.63g) was obtained with C. procera. These plants materials were found to also affect the egg-laying capacity of C. maculatus. Treatment with C. odorata recorded significantly(P<0.05) higher number of eggs laid at all concentrations, though the egg-laying capacity was also concentration-dependent; whereas C. procera recorded the least number of eggs laid. All the three plants powders tested demonstrated significant insecticidal potency on stored cowpea weevils, with C. procera and C. odorata showing significantly higher and lower insecticidal potentials respectively. These findings will help in solving problem associated with food security especially with respect to stored produce. [ABSTRACT FROM AUTHOR]