An artificial non-flying mutation to improve the efficiency of the ladybird Harmonia axyridis in biological control of aphids

The use of coccinellids in the biological control of aphids is restricted t o the release of larvae because adults tend to fly away. Non-flying adults may stay longer in one place and so they and their progeny could give longe r term protection to plants. This work is an attempt to produce a non-flyin g population by the use of a chemical mutagen and selection of adults with wing malformations through their subsequent generations. These adults are c haracterized by open elytra and extended wings. Some general features of th is mutation were disclosed. The mutation is either unexpressed or results i n malformed wings. It also seems recessive and lethal when homozygous. The adults with the mutation suffered a high level of mortality and a drastic r eduction in reproductive capacity that prevents their mass rearing for biol ogical control. This study revealed a negative relationship between wing ma lformations and reproductive capacity. Nevertheless, when adults with the m utation were released in greenhouses containing cucumbers infested with the aphid Aphis gossypii, they remained on the plants in higher numbers and la id eggs over a longer period of time than the control adults but their prog eny were less numerous.