Stage-wise Morphometric Characterisation of Mustard Aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae) under Laboratory Conditions

Abstract

Aims: To characterise the morphometric features of four nymphal instars, apterate adults and alate adults of Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae) reared on mustard under laboratory conditions. Study Design: Laboratory-based morphometric study. Place and Duration of Study: P. G. Research Laboratory, Department of Entomology, N. M. College of Agriculture, Navsari Agricultural University, Navsari, Gujarat, during rabi 2024. Methodology: Four nymphal instars and two adult morphs, apterate and alate, were examined for body and appendage dimensions. Body length and body width were recorded from 30 specimens for each developmental stage or adult morph, whereas antennal, cornicle, caudal and leg dimensions were recorded from 15 specimens per stage or morph. Results: Mean body length increased from 0.73±0.03 mm in the first instar to 1.59±0.04 mm in the fourth instar, while mean body width increased from 0.38±0.02 to 0.82±0.05 mm. Mean antennal length increased from 0.47±0.04 to 1.03±0.04 mm and mean cornicle length from 0.07±0.01 to 0.16±0.01 mm across the nymphal instars. Mean hind-leg length increased from 0.58±0.04 to 1.29±0.12 mm. The Apterate adult measured 1.84±0.08 mm in length and 1.14±0.03 mm in width, whereas the corresponding values for the alate adult were 1.79±0.08 and 1.05±0.02 mm. Distinct differences were recorded in antennal, cornicle, caudal and leg dimensions among stages and adult morphs. Conclusion: The study provides stage-specific morphometric information that can support the identification and differentiation of developmental stages and adult morphs of L. erysimi under laboratory conditions.