Final answer:
Insects such as fireflies that are active at dawn and dusk show a crepuscular activity pattern.
Step-by-step explanation:
Insects such as fireflies that are active at dawn and dusk exhibit a specific activity pattern called crepuscular. Crepuscular animals are most active during twilight, which is the period of time between daylight and darkness. Fireflies use their unique flash patterns to communicate with each other, and their activity during dawn and dusk is part of their reproductive behavior.