Pranita Roy, Suresh R Jambagi, K Logeswaran, Doddachowdappa Sagar, M Mohan, G Mahendiran, D Nandhini
The potato tuber moth, Phthorimaea operculella (Lepidoptera: Gelechiidae), is a destructive pest of potato worldwide. Comprehensive studies on its reproductive morphology and egg ultrastructure are highly essential, as they are fundamental to understanding reproductive biology and provide valuable baseline information for the development and implementation of emerging genetic control strategies. The reproductive system and egg chorionic ultrastructure of P. operculella were comprehensively characterized using stereomicroscopy and scanning electron microscopy (SEM) respectively. Adult reproductive organs were dissected and examined, while egg morphology and chorionic architecture were analysed at high resolution using SEM. The female reproductive system comprised paired ovaries with four polytrophic meroistic ovarioles, but a rare asymmetrical arrangement (5 +4) was also observed. The male reproductive system exhibited fused adult testes, seminal vesicles, paired accessory glands, vas deferens and a well-developed intromittent organ. Eggs were elliptical, measuring 473 ± 9.89 μm in length and 325 ± 6.87 μm in breadth, with a distinct reticulate chorion. SEM revealed pronounced regional specialization, including a micropylar apparatus consisting of an irregular micropylar plate surrounded by 5-9 primary petaloid rosette cells and secondary rosette cell, 15-22 first order polygonal cell and 19-28 second order polygonal cell, whereas the opposite pole contained numerous aeropyles with comparatively reduced sculpturing. Polygonal chorionic cells predominated over the anterior surface, while adhesive secretions firmly anchored eggs to host tissues. The findings offer essential information for future studies on developmental biology, reproductive physiology, RNA interference, CRISPR-based genome editing, and sustainable genetic management of this important pest.