Sexual Wing Shape Dimorphism in Piophila casei (Linnaeus, 1758 Diptera: Piophilidae)

Abstract

The Piophilidae are synanthropic flies that grow and develop on cheese, fish, cured meat, among others substrates. Some species represents an important forensic indicator associated to carcasses, because the adults are common during the bloat stage, and the larvae are associated to the advanced to dry stages. Recently, the geometric morphometrics has been used to quantified the sexual shape dimorphism in medical important insects. We proposed to evaluate the shape sexual dimorphism in Piophila casei through the wing geometric morphometrics. Were collected 34 P. casei specimens and sorted by sex (17 females and 17 males), later the wing was dissected and slide mounted for digitalizing eight landmarks. The x, y coordinates were aligned by Generalized Procrustes Analysis to extract the matrix configurations and centroid size. The sexual shape dimorphism differences were evaluated by means a Discriminant Analysis (DA), and the size with non-parametric ANOVA. We didn't found differences in centroid size between females and males; however, the shape was significantly different between sex. In the cross-validation DA, 82% specimens were correctly classified into females and 88% males. Our study represents the first investigation that quantifies the sexual shape and size dimorphism in Piophila casei, and this could be a basis for further studies that combines geometric morphometrics tools and forensic entomology.