Completely serious.
Nature directs invertebrates that are living in your pond muck, or on the rooted vegetation to emerge simultaneously to facilitate the mating process. Theories include water temperature, solar period and lunar cycles, but these invertebrates need to take wing at around the same time in order to maximize their mating opportunity. The fish either know this intuitively, or learn it through experience, but I've seen literally hundreds of times when bluegill gang up on these "buggies" as they hit the surface, shed their carapace and take flight.
Trout are well known for doing the same thing.
