The question is too broad. Some insects are active a night (nocturnal), or near dawn/dusk (crepuscular). Some insects respond to a bright light at night, while others do not. Light trapping for moths is one useful application of this result. Be careful as insects can see outside the spectrum visible to people. Be careful as a bright light to you may still seem dark, or what seems dark to you may seem like sufficient light to the insect. Can you provide more details? Photophase and scotophase are two other key words.