Sleep restores and rejuvenates. Without it, our minds aren't as sharp, and our reflexes become dull. Scientists know for sure that birds, reptiles, and other mammals experience brain wave patterns similar to our own during periods of rest. But what about insects? Do bugs sleep?
It's not quite as easy for us to tell whether insects sleep the way we do. They don't have eyelids, for one thing, so you'll never see a bug close its eyes for a quick nap. Scientists haven't found a way to study insect brain activity, as they have in other animals, to see if typical rest patterns occur.
Still, by most accounts, the answer is yes, insects do sleep. Insects clearly rest at times, and are aroused only by strong stimuli – the heat of day, the darkness of night, or perhaps a sudden attack by a predator. This state of deep rest is called torpor, and is the closest behavior to true sleep that bugs exhibit.
Migrating monarchs fly by day, and gather for large butterfly slumber parties as night falls. These sleep aggregations keep individual butterflies safe from predators while resting from the long day's travels.
Some bees have peculiar sleep habits. Certain members of the family Apiadae will spend the night suspended by only the grip of their jaws on a favorite plant.
Torpor also helps some insects adapt to life threatening environmental conditions. The New Zealand weta lives at high elevations where nighttime temperatures get quite icy. To combat the cold, the weta simply goes to sleep at night, and literally freezes. In the morning, it thaws out and resumes its activity. Many other insects seem to take a quick nap when threatened – think of the pillbugs that roll themselves into balls the moment you touch them.