The impact of color on host selection by asexual and sexual Trichogramma brassicae (Hym.: Trichogrammatidae)

Trichogramma brassicae Bezdenko (Hym.: Trichogrammatidae) is one of the most widely used parasitoids of lepidopteran key pests around the world. This species has two reproductive modes, arrhenotoky and thelytoky, the second one is caused by an endosymbiont bacterium which is called Wolbachia. Colors have been mentioned as one of the factors which influence the oviposition of parasitoids. The present study examined the effect of the color patch and quality on oviposition of Wolbachia-infected and uninfected T. brassicae population. At the first, sterile eggs of Ephestia kuehniella Zeller (Lep.: Pyralidae) as laboratory host of both populations were glued on colorful patches included; blue, green, yellow, orange, red, and white, with 30 repetitions for each populations. Colorful papers and cellophanes were used as patches. Both cardboard and cellophane patches were placed in an equal distance from each other in cylindrical containers. All females were separated from E. kuehniella eggs after 24 h. The results showed significant differences in the oviposition rate of infected and uninfected T. brassicae on colorful papers while there were not any significant differences in the oviposition rate of both populations on colorful cellophanes. The results showed that asexual and sexual populations responded differently to colorful papers although females of both populations were able to discriminate between the color of paper patches.