EGG SIZE, YOLK MASS EXTRUSION AND HATCHING BEHAVIOR IN 2 CRYPTIC SPECIES OF ANASTREPHA-FRATERCULUS (WIEDEMANN) (DIPTERA, TEPHRITIDAE)

Variations in egg length were observed for two populations of cryptic species of Anastrepha fraterculus (Wiedemann). The eggs of type I flie s were smaller than those of type II individuals. For both types, in r egard to yolk mass extrusion, four classes of embryos were detected. C lass 1: embryos that extrude masses at both extremities; class 2: embr yos in which extrusion occurs only at the anterior pole; class 3: embr yos that eliminate mass only at the posterior pole, and class 4: embry os that do not extrude any mass. Embryo class frequencies were similar for populations belonging to the same type, but different between typ es. Individual females may produce eggs from different embryo classes, but for any given female the pattern remains constant during a long p eriod of oviposition. Variation in size of the extruded masses was sim ilar for both populations. Individual females produced embryos with a small range of mass diameters, and different females produced masses o f different mean size. However, individual mass size remained constant during oviposition. The results suggest the existence of genetic comp onents involved in the control of this unusual process. Larvae of both types presented, just before eclosion, similar unusual behaviors: the y ingest the anterior extruded mass, rotate 180 degrees, absorb the po sterior mass and eclose near the posterior pole. Data show that crypti c A. fraterculus type I and type II differs in regard to egg size as w ell as to the phenomenon of yolk mass extrusion.