Effects of Cold Storage Duration and Pupal Age on Eclosion, Fitness, and Progeny Performance in the Predatory Midge Aphidoletes aphidimyza

ABSTRACT

Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) is an important predatory midge and one of the key agents employed in the augmentative biological control of aphids, which are major pests of many crops globally. In this study, we evaluated the effects of cold storage duration (7, 14, 21, and 28 days at 8°C) and pupal age (1–7 days) on this predatory midge. Following cold storage, we assessed eclosion timing and rate, adult longevity, and fecundity, as well as egg hatching rate and larval predation capacity of the progeny. Both pupal age and storage duration significantly affected eclosion. Pupae aged 3–5 days maintained eclosion rates above 80% under storage for ≤ 14 days, whereas storage beyond 21 days markedly reduced both eclosion and adult longevity. In particular, eclosion rates of 6–7‐day‐old pupae fell below 30%, and adults completely lost oviposition ability after 28 days of storage. Adult longevity declined with prolonged storage but remained unchanged within the first 7 days. Fecundity was significantly reduced when storage exceeded 21 days, irrespective of pupal age, whereas the egg hatching rate of the progeny was unaffected by either factor. Additionally, storage for up to 14 days had no significant impact on predation capacity across pupal ages, although certain age–duration combinations resulted in significant decreases. Overall, using 3–5‐day‐old pupae stored at 8°C for no more than 14 days ensured high eclosion rates and adult fitness while preserving progeny predation capacity. These findings provide key technical parameters to support the commercial production and field application of A. aphidimyza .