Plankton in the Sky? Challenge Question: "Why would there be more insects and spiders floating in the air during daytime than at night?" During the day, the sun produces thermal air currents that can hold many things aloft. Thermals are strong enough to hold up huge hawks and eagles as they migrate, so they can certainly hold up a tiny insect or ballooning baby spider! Also, winds and updrafts are much stronger in the daytime than at night, making it a breeze for more insects and spiders to float away. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form