Number of Sperm Bundles in the Duplex of Tobacco Bud worms (Lepidoptera: Noctuidae) as a Function of Age

Abstract

With the first photophase after adult eclosion (≈6 h), eupyrene sperm bundles began to accumulate in the duplex of males of the tobacco bud worm, Heliothis virescens (F.). The movement of sperm bundles from the seminal vesicles to the duplex followed a daily cycle, and the increase in number of sperm bundles within the duplex was linear. Thus, by counting the number of bundles in the duplex, one could estimate the age of virgin males. The number of bundles in the duplex was similar among three strains of tobacco bud worms colonized from 1 to <15 generations. Further, the number of bundles in males reared from eggs collected from cotton, tobacco, or pigeon pea was similar to that of other males and did not differ with weekly collection (5 July-13 September). All the sperm bundles within the duplex were transferred to the female during mating. Thereafter, daily accumulation of sperm bundles within the duplex was cyclic and linear. Thus, one could estimate the number of days since mating by counting the sperm bundles in the duplex. The color of the material within the simplex indicated mating status. Males with a light-yellow or darker-color simplex were virgin. The material was clear or white in mated males.