Morphological changes in Chilo partellus (Swinhoe) undergoing diapause

Abstract

The purpose of this work was to provide a practical pictorial guide for identification of diapausing larvae of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) based on morphological and morphometric characteristics in the laboratory of Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi, India during February, 2014. On the basis of pictorial guide, the larvae of C. partellus which completely lack cuticular pigmentations, markings, spots and asetose tubercle are the distinctive diapause larvae. Transitional morphs are less conspicuously pigmented and considered as intermediate of non-diapausing (spotted morphs) and diapausing larvae (immaculate morphs). There was significant reduction in body weight, size and head capsule width in diapause than the non-diapause larvae. The pupal and adult sizes of diapause experienced population were smaller than the non-diapausing counterparts. Adults emerged from diapausing larvae were darker in color than those emerged from non-diapausing larvae. This pictorial key to identify diapausing larvae will be highly useful for the entomologists working on diapause, and the agriculture practitioners to find and kill diapausing larvae of C. partellus in their resting sites to disrupt further multiplication.