Insects
Bactrocera dorsalis used in this study were reared at the Animal Rearing and Quarantine Unit of icipe , following the procedures described by Ekesi and Mohammed (2011). For this experiment, adults with similar scutum colouration pattern (Fig. 1) were separated from the mass-reared colony, kept in Perspex cages (80 × 80 × 80 cm) and maintained at 25 ±1°C, 60 ±10% RH and a photoperiod of L12:D12 for more than 30 generations before the start of experiments. These adults were fed on an artificial diet consisting of a mixture of sugar and ultrapure grade enzymatic yeast hydrolysate (USB Corporation, Cleveland, Ohio, USA) at the ratio of 3:1 by volume and were provided with water in a Petri dish (8.6 cm diameter) with a layer of pumice granules to prevent drowning of the flies.