Diaphania angustalis Snellen (Lepidoptera: Crambidae) has emerged as a very important pest of blackboard tree, Alstonia scholaris (L.) R. Br. (Apocynaceae), in China during the last two decades. Understanding its biology and behavior is crucial for designing effective and environmentally friendly pest management strategies. Under laboratory conditions [25–28°C, 12:12 (L:D) h, 75–80% RH], adults emerged during both light and dark hours with peak emergence occurring between the first and fifth hours of scotophase, and unmated males and females lived for a mean (±SE) 5.4 ± 0.4 and 5.3 ± 0.7 d, respectively. Female calling behavior was observed only during scotophase (peaking in the fifth hour) by 1- to 5-d-old females, and mating activities occurred 2–5 d after emergence, peaking on day 3. These behavioral characteristics could inform control programs targeting adults.