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 to 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 longer term protection to plants. This work is an attempt to produce a non-flying population by the use of a chemical mutagen and selection of adults with wing malformations through their subsequent generations. These adults are characterized by open elytra and extended wings. Some general features of this mutation were disclosed. The mutation is either unexpressed or results in malformed wings. It also seems recessive and lethal when homozygous. The adults with the mutation suffered a high level of mortality and a drastic reduction in reproductive capacity that prevents their mass rearing for biological control. This study revealed a negative relationship between wing malformations and reproductive capacity. Nevertheless, when adults with the mutation were released in greenhouses containing cucumbers infested with the aphid Aphis gossypii, they remained on the plants in higher numbers and laid eggs over a longer period of time than the control adults but their progeny were less numerous.