A semi-artificial rearing system for the specialist predatory ladybird Cryptolaemus montrouzieri

Abstract

In the present study a semi-artificial rearing system for the Australian ladybird Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), a specialist predator of mealybugs, was developed. In a first step, a rearing system using eggs of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) as a food and synthetic polyester wadding as an oviposition substrate was compared with a natural rearing system using the citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), as to its effects on the predator's developmental and reproductive parameters. In a second series of experiments the performance of C. montrouzieri on bee pollen or on a mixture of E. kuehniella eggs and bee pollen was assessed. E. kuehniella eggs proved to be a suitable food to support larval development of the predator. Ladybird larvae reared on flour moth eggs developed two days faster and weighed approximately 10 % more than their counterparts reared on mealybugs. Despite a prolongation of the preoviposition period with ca. eight days and a decrease in egg hatch by about 10 %, C. montrouzieri females fed moth eggs accepted the synthetic wadding as an oviposition substrate and deposited the same number of eggs their counterparts maintained on mealybugs. A mixture of E. kuehniella eggs with pollen yielded similar developmental and reproductive rates as E. kuehniella eggs alone, but a diet of bee pollen alone was not adequate for the predator. Our findings indicate the potential of a rearing system using E. kuehniella eggs as a factitious food and synthetic wadding as an artificial oviposition substrate for the mass production of C. montrouzieri

Prey range of the predatory ladybird Cryptolaemus montrouzieri

“…Eggs of G. mellonella were not a suitable food source for C. montrouzieri: only 2 % of the larvae reached the adult stage when fed G. mellonella eggs and not a single female produced eggs when provided with this food source. In contrast, the eggs of another member of the Pyralidae family (E. kuehniella) were found to be a suitable factitious food source for both development and reproduction of this ladybird (Attia et al 2011;Maes et al 2014). Although M. persicae and A. pisum belong to the same family of Aphididae, C. montrouzieri performed differently on these aphid species.…”

“…Furthermore, the western flower thrips, Frankliniella occidentalis (Pergande)(Thysanoptera: Thripidae), was selected as another economically important hemimetabolous pest insect. Because eggs of the flour moth E. kuehniella constitute an adequate factitious food source for C. montrouzieri (Attia et al 2011;Maes et al 2014), we also tested the predator's ability to develop and reproduce on eggs of two other species in the framework of its risk assessment. The greater wax moth, Galleria mellonella L. (Lepidoptera: Pyralidae), was selected based on its taxonomic relatedness to E. kuehniella.…”

“…Water was provided by way of a moist piece of cotton wadding fitted into a 1.5 cm plastic dish. A larger piece of dry cotton wadding (5 9 5 cm) was offered to adult beetles and served as an oviposition substrate for females (Maes et al 2014). Individuals of the 12th and 13th generations were used in the experiments.…”

“…Prey species Prey range of the predatory ladybird 731 that proved to be less suitable to support the development of C. montrouzieri (based on immature survival rate, developmental time and adult body weight of the predator) were subjected to a further laboratory experiment, in which their potential for the reproduction of C. montrouzieri was assessed. In the latter experiment, ladybird larvae were reared to adulthood on a diet of E. kuehniella eggs, which was found to be an adequate food source for C. montrouzieri larvae (Attia et al 2011;Maes et al 2014), and switched to one of the candidate prey species once they reached the adult stage. This was done for all candidate prey species, except for the aphids M. persicae and A. pisum.…”

“…In augmentative biological control, C. montrouzieri is mostly released as adult. Therefore, we also assessed the reproductive capacity of ladybirds that received one of the candidate prey during their adult life, but had been reared on a nutritionally suitable food source (eggs of the flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)) during their larval stages (Attia et al 2011;Maes et al 2014). …”