Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) calling behavior changed with age. The percentage of calling females 1–4 days old was 20, 33, 91, and 95% respectively. Duration and spacing of calling bouts varied considerably within the same age group. Fourday-old females had the longest total duration of calling (X= 117 min.). The number of calling bouts also changed significantly with age. Four-day-old females called most often with 21 bouts/night. Regardless of age, bout length was mostly 1 min or less, but the oldest females had the longest bouts. As moths aged, calling commenced earlier in the scotophase, with 4-dayold females calling earliest. Thus, sexually mature moths are more competitive than their younger counterparts by calling and attracting males first.