Role of egg buster in hatching of Aedes aegypti: scanning electron microscopy study.

Egg hatching has been studied in Aedes aegypti (L.) through scanning electron microscopy. The first sign of egg hatching is a small protrusion on the eggshell in the anterior pole. The larval movement provokes a crack in the eggshell with the egg buster located in the dorsal head. The egg buster provokes a small transverse fissure in the eggshell that gradually increases in the chorion. Then, the rupture is completed around the eggshell. The separation of the anterior pole occurs, showing the dorsal region of the larva head with the egg buster and the cap. After sequential movements, the larva looses the cap. Finally, the first instar is ready to be free showing details of its body with the egg buster over its head. This structure is a cuticular formation, similar to a cone structure that ends in a very fine tip and emerges from a pear-like depression with high rounded borders. Our results describe the anatomy of the egg hatching process in Ae. aegypti, showing details of the participation of the egg buster.