Teratology of the beetle Tenebrio molitor: III. Ultrastructural alterations in the flight musculature of the pupal-winged adult

Abstract

The present report deals at an ultrastructural level with some of the internal aspects of a malformation or teratology (“pupal-winged adult”) found in the beetle Tenebrio molitor. The flight muscle of two types of pupal-winged adults was examined, and the pattern of muscular degeneration in the teratological insects is presented. By comparison with normal Tenebrio flight musculature, it is seen that, while externally the wing of the pupal-winged adult is pupal in form, the ultrastructural characteristics of the flight muscle are those of an adult beetle. The fine structural alterations in the flight muscle of the teratological insects include disorientation and dissolution of myofilaments, alterations in the Z lines, hypertrophy of the sarcoplasmic reticulum, glycogen abnormalities, and swelling, enlargment, and destruction of mitochondria. The possible metabolic dysfunctions that lead to, or result from, the ultrastructural alterations are considered.