Effects of colours and synthetic odours on the attraction of Glossina pallidipes and G. morsitans morsitans to traps and screens

Glossina morsitans morsitans Westw. and G. pallidipes Aust. flying around and landing on coloured screens and traps were sampled using electrocuting nets. External colour affected both attractiveness and efficiency of traps, such that yellow and green traps were unattractive and inefficient; black and red, attractive and inefficient; white, moderately attractive, and very efficient; and blue traps, attractive and efficient. The order of attractiveness of coloured screens was similar to that for traps. Landing responses were generally strongest on black surfaces, and weakest on white, but the results for blue were variable. Carbon dioxide and acetone odours improved trap catches and also eliminated most catch differences between traps differently coloured on their outer surfaces. The relative performances of traps coloured differently on inside surfaces only were not affected significantly by these odours, and in all cases black or red target areas inside the trap were required for optimum trap performance. When acetone and 1‐octen‐3‐ol odours were used, catches were improved but the relative performance of differently coloured traps and screens was not changed. There were no obvious species differences in colour responses although numbers of G. morsitans were too low for statistical comparisons.