Influence of adult diet on the development of the reproductive system and mating ability of Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

S. Vijaysegaran, G.H. Walter and R.A.I. Drew

Abstract

The influence of a complete diet (hydrolysed yeast plus sucrose) on the development of the reproductive system and mating abilities of both sexes of adult Queensland fruit fly Bactrocera tryoni (Froggatt) was investigated. Females needed a complete diet for sexual maturity development but in females provided with only sucrose, practically no development occurred. The ovaries, accessory glands and fat body were all affected. The male reproductive system was also influenced negatively by an inadequate adult diet. Although the testes were apparently not adversely affected, the accessory glands grew more slowly and were much smaller than in hydrolysed yeast-fed males. In an experimental group, the erecting and pumping organ was smaller than normal and the odour of volatiles released on rupture of the pheromone reservoir was weaker, as judged by human perception. Mating tests revealed the influence of a deficient diet on males mating ability, fertility and competitiveness. Hydrolysed yeast-fed males and females mated assortatively when exposed in a combination of both sexes (in both diet combinations). Males on an incomplete diet were only about a quarter as competitive as normal males. The mating ability of males fed an incomplete diet did not improve with age and their mating ability in a competitive environment remained inferior, but males deprived initially of a complete diet did have their mating ability restored by subsequent feeding on hydrolysed yeast. The implications of these findings for sterile insect release programmes are discussed.

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