Life Cycle of Laboratory-Reared Acrobasis nuxvorella Neunzig (Lepidoptera: Pyralidae): A Pecan Nut Pest

Abstract

Acrobasis nuxvorella Neunzig is a monophagous pest that feeds on pecan nut trees, Carya illinoinensis. Its specific feeding habit makes the reproduction of this insect in the laboratory challenging. The objective of the present work was to replicate the biological cycle of A. nuxvorella under laboratory conditions. Different instar larvae of the insect were collected from infested nut trees. The larvae were fed with a simple diet consisting of immature frozen nuts (-20°C) that were ground before use. We managed to complete the whole life cycle and to record the dates of the appearance of pupae, the emergence of adults, egg laying and egg hatching. These eggs gave origin to the second larvae generation. The laboratory conditions to maintain the moths consisted of a photoperiod of 16:8 h at 25±2°C and 60±5% of RH. The total duration of the cycle was 45 days, which is similar to the duration of the natural cycle in the field. The emergence of adults was 83%. The time of larval development was longer than the time spent as pupae and this latter was longer than the time spent as eggs. Hatching occurred four days after oviposition (time 0) and ecdyses of the remaining four larval instars lasted an average of 22 days in total. The pupal stage, during which they did not feed, lasted between 10 to 14 days and the adult life lasted 8 to 10 days. These results allow the standardization of the conditions needed to rear A. nuxvorella in the laboratory, which was not possible until now. Furthermore, this breakthrough will improve techniques to control and manage this insect.