Survival of Plodia interpunctella (Hübner) larvae treated with 98% N₂ and the life history of their next generation

Abstract

Understanding the development and reproduction of insects surviving controlled atmosphere treatment may help in developing sound pest management strategies. The developmental duration, survival percentage, and oviposition of Plodia interpunctella and its F1 generation were determined after the fifth instar larvae (the last-stage larvae) were exposed to 98% N2 for different exposure times. The survival percentage of the last-stage larvae treated with 98% N2 for 6, 4, 1.5, and 0 day was 70, 80, 91, and 100%, respectively when measured 24 h after treatment. The survival percentage of the last-stage larvae that developed to pupae was 37, 55, 73, and 96%, corresponding to the different exposure times. The developmental time needed to pass from pupa to adult emergence of specimens treated as the last-stage larvae were 8, 7, 6, and 6 days corresponding respectively to high N2 treatment after 6, 4, 1.5, and 0 day of exposure. The mean number of eggs laid by the subsequent females developed from the treated last-stage larvae was 35, 66, 81, and 123, respectively. The oviposition inhibition ratio of the F1 generation decreased by more than 33% compared with that of the parental generation. When the last-stage larvae were exposed to 98% N2 for longer than 4 days, the immature developmental time of surviving individuals in the F1 generation was delayed more than 6 days due to slower egg hatching and longer development of the first and second instar larvae stages. The population trend index of the F1 generation was lower when raised from the treated last-stage larvae than those from untreated controls.

Life-table parameters of Plodia interpunctella (Lepidoptera: Pyralidae) on different stored date palm fruits under laboratory conditions

“…For this purpose, males and females (20 pairs) were released in plastic containers (10 cm diameter and 5 cm height), and 10 g of dates of each variety was placed separately in each container. The male and female sexes were separated from the larval stage in such a way that the male larva have dark patch formed by the testis, which is visible in the medium plane of the mid-dorsal abdomen, while the female larvae have no visible patch ( Allotey and Goswami 1990 , Huang et al 2023 ). Also, females are generally larger than males and have an expanded abdomen ( Mason 1984 ).…”