Phenotypic plasticity of predatory mite Amblyseius orientalis in response to diet switch

Abstract

Phenotypic plasticity, especially the ability to switch to new dietary sources is essential to invertebrates for survival and reproduction in variable environments. Amblyseius orientalis Ehara (Acari: Phytoseiidae) is an effective predatory mite to control spider mites in orchards, whereas its preys or artificial diets used in mass rearing productions are distinct from the field pests. It’s unknown if predator performance could recover immediately after diet change from rearing condition to pest management. In this study, we assessed life-history performances and predation in four populations of A. orientalis which were fed by two preys (Tetranychus urticae and Carpoglyphus lactis) in respective parental and offspring generations to evaluate the phenotypic plasticity and dietary adaptation of A. orientalis progeny. The results showed that prey species switching in two generations had great influence on predator’s developmental time and longevity. The longevity of A. orientalis reduced from 32.98 to 24.22 days while parent and progeny feeding on different preys. However, the sex ratio, fecundity, prey consumptions of progeny were not different among four populations. The sex ratio of four populations of A. orientalis also showed the consistence of a female-biased trend from 1.57 to 1.75, and the lifetime reproductions were almost equivalent from 25.82 to 28.06 eggs per female. Prey consumptions were similar among A. orientalis females and changed between 21.41 to 23.23 eggs per day. Overall, our study demonstrated that A. orientalis has higher fitness plasticity and does not need long time to adapt the new diet, therefore it can be applied as an outstanding biocontrol agent in pest management after diet change from production to the field.