Comparison of different designs of the OBS. Average number of female mosquitoes caught per night inside the different OBS designs. The highest number of mosquitoes was caught when the OBS had side openings and no barrier on the eave spaces. The alphabetical symbols, a, b and c are used to represent differences as determined by Tukey's test. Trapping efficiencies are not significantly different (P = 0.05), if the different bars representing the designs share any of these alphabets. Designs sharing symbols are not significantly different The Y-error bars represent 95% confidence intervals.