Development and diapause induction of the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) at different photoperiods

Abstract

Diapause concerns the fascinating phenomenon in the biology of insect development which allows better understanding the local adaptation and phenotypic plasticity to seasonal variations in environment. There is lot of reasons to carry out the research on diapause both for fundamental and applied sciences. Photoperiod is one of the main environmental cues followed by insects to predict the forthcoming seasonal changes and to adapt these changes in their life-history traits. Thus, the effect of different photoperiod regimes on development and diapause induction of larvae of the Indian meal moth Plodia interpunctella (Hübner) was evaluated at a constant temperature of 17 °C. Development was significantly faster at a photoperiod of 12:12 light:darkness (L:D) than at 8:16, 10:14, 14:10 and 16:8 L:D. A photoperiod of 12:12 (L:D) induced most larvae (≥ 71%) to enter diapause, while this percentage was slightly lower (60%) at both shorter(8 h) and longer (16 h) day lengths (50%). The different photoperiod regimes did not affect the percentage of adult emergence. Fat and protein composition of the diapausing larvae differed significantly among treatments as well as between diapausing and non-diapausing larvae. Larvae developing from 8:16 (L:D) contained the maximum amount of protein (36.8%) compared to other regimes, while the minimum amount (21.0%) was noted in larvae that developed at 16:8 (L:D). Six types of fatty acids were detected in the larvae: myristic acid (methyl tetradecenoate), palmitoleic acid (9-hexadecenoic acid, methyl ester), palmitic acid (hexadecenoic acid, methyl ester), linoleic acid (9, 12-Octadecadienoic acid (Z, Z), methyl ester), oleic acid [9-octadecenoic acid, methyl ester (E)] and stearic acid (octadecanoic acid, methyl ester). The results also reveal that the percent of fatty acids detected in the diapausing larvae varies significantly and the same trends imply in the interaction of fatty acid and photoperiod regimes. Moreover, three quarters of the total variance was accounted for by the Principal Component Analysis (PCA) of the fatty acids. Different proportions of fatty acids were noted among treatments, suggesting that photoperiod influences a number of key biological traits in P. interpunctella, much more than the percentage of the diapausing larvae per se.

Function of temperature on almond moth demographic characteristics: Do diapausing individuals contribute to population growth rate?

“…At 20°C, some individuals were observed with retarded development and wandering behavior. According to the de nition of diapause by Bell and Bowley (1980) and Hasan et al (2020), these larvae were considered to be the diapausing individuals used in our study They could be distinguished based on several criteria: larvae that did not develop into pupae within two weeks (which was after the pupation peak of their non-diapausing cohort), and their large size with yellow color.…”

“…Therefore, low temperature management, i.e., keeping the storehouse at reduced temperatures is an ideal method for controlling stored-product insect pests based on its effectiveness on retarding or stopping the growth, feeding, and breeding of these insects. Low temperatures, however, may also act as a regulating factor in inducing insects to enter diapause (Bell 1975;Hasan et al 2020). Stored-product moth species, which normally enter diapause in the late larval instar stage, can be identi ed by the extended larval developmental time.…”

Taxonomic Description, Distribution, and Control Measures of Plodia interpunctella (Hübner, 1813) in Kashmir Valley, India

“…With its wide range of food preferences, the Indian meal moth is a significant stored product pest that results in substantial losses and quality degradation of the products, particularly dry fruits. P. interpunctella is undoubtedly the most predominant species of postharvest stored products, as several monitoring studies indicate that the Indian meal moth is globally distributed [7][8][9] (Figure 1).…”