Hourly captures of male black cutworms,Agrotis ipsilon(Hufnagel), in traps baited with different ages of virgin females (2, 4, 6, and 8 d) were examined during three phases of phenology in Iowa: migration–infestation, early postinfestation, and mid-postinfestation. Six-d-old virgin females captured the most males during migration-infestation, whereas traps using 4-d-old females, although not statistically significant, captured the most males during early postinfestation. Two factors, greater capture rate and longer capture period, were responsible for the enhanced attractiveness of 6-d-old females during migration–infestation. Only capture rate contributed to increased attractiveness of 4-d-old females during early postinfestation. Trap captures during mid-postinfestation were extremely low despite active calling by females and possibly reflected the beginning of reproductive diapause in males. Nocturnal rhythms of capture were similar across virgin female ages and seasons. Likewise, comparisons with a trap baited with synthetic pheromone revealed similarities that suggest that the nightly rhythm of mating activities is mediated primarily by the male.