Eggshell morphology in two cryptic species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

Abstract

The external morphology of eggs of 2 cryptic species of the Anastrepha fraterculus (Wiedemann) complex, species 1 and species 2, was studied by scanning electron microscopy. Eggs of species 1 are, on the average, shorter than those of species 2 whereas they do not differ in their cross diameter. In species 1, the egg apex is asymmetric and papillate, whereas in species 2, the end is blunt and symmetrical. The micropyle is located on the dorsal side of the papilla in species 1 and near the egg apex in species 2. The anterior end of both types of eggs is decorated by a lattice of ridges in a polygonal arrangement. The sculpturing of the chorion covers a larger area of the anterior pole in species 1 than in species 2 eggs. In the remainder of the egg, the chorion is smooth without any clear reticulation. In species 2 eggs, the polygons near the micropyle are arranged in a rosette configuration which is absent in species 1. Aeropyles were found almost exclusively in the chorionic ridges on the ventral side in both types of eggs. Eggs of species 1 have a larger number of aeropyles than those of species 2. The external morphology of the eggs presents reliable characteristics that distinguish the 2 cryptic species of A. fraterculus.