Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is a major pest of fruits in the family Solanaceae in the Western Hemisphere. The objectives of this study were to determine whether life zone or host plant explained morphological variation in females, and if so, if there was evidence of sexual selection driving diversification in this species. We collected larvae feeding on cultivated (Capsicum annuum L., Solanum betaceum Cavanilles, Solanum lycopersicum Lamarck, Solanum melongena L., and Solanum quitoense Lamarck) and wild species (Solanum atropurpureum Schrank, Solanum acerifolium Dunal, Solanum crinitum Lamarck, and Solanum hirtum Vahl) of Solanceae in Colombia. The genitalia traits of 547 reared females were measured and correlations with host plant fruit size were estimated. Six female genitalia morphological characters, apophysis posterioris, apophysis anterioris, ostium bursae, ductus bursae length, corpus bursae, and the seventh abdominal segment were measured. Principal component analysis and cluster analysis classified individuals based on female morphological similarity and clustered them into four main groups according to host plant: 1) S. aceriflolium; 2) S. quitoense, S. lycopersicum, C. annuum and S. hirtum; 3) S. atroporpureum; 4) S. melongena, S. crinitum and S. betaceum. In this unique study, we found that variation in female genitalia size is directly correlated with the size of its host fruit, which suggests a mechanism for reproductive isolation and divergence of the four host races. Ours is one of the first studies that shows female genitalia morphology is correlated with species of host plants and represents a valuable contribution to the study of sexual selection in the evolution of insects.