Mayflies are fascinating creatures. You can learn more detail about their short adult lives and how they are one of the oldest groups of living insects in these links. People are interested in mayflies for many other reasons, too. For stories about people interested in mayflies and what is happening to mayflies worldwide, see this article from the Washington Post. As you saw in the video, mayflies are important food for different kinds of fish, and some folks make fishing lures that look like mayflies or other aquatic insects. You can get hooked on mayflies for fishing at troutnut.com. 

Various government and citizen groups worldwide are concerned about mayflies and healthy water in their communities. Several excellent online resources have been developed to help people discover and identify mayflies and other stream invertebrates near them. Examples include this site for eastern North America, this site for the UK, and this site for New Zealand. Scientists also study many different aspects of mayflies. You can read more about current research involving mayfly biology at the Stroud Water Research Center. Purdue University keeps information about the diversity and distribution of mayflies in North & Central America and the Caribbean, and you can see cool images of mayflies there.