Swimming pools will attract certain aquatic insects every year, but the lure of the water may bring in many other creatures.
The most dramatic are thrips, tiny elongate yellow insects. They may be drawn to water after being driven from recently cut hay fields. On normal days thrips use their abrasive mouthparts to rasp at plant tissue, especially flowers. However, they will scrape skin, perhaps as they attempt to pick up small amounts of moisture. An occasional thrips scrape probably is tolerable but lots of them do not add to the swimming experience. A strong jet of water may be used to plaster them to decks and other surfaces where they have accumulated.
Honey Bees and Paper Wasps
Honey bees need water to air condition their hive. They are able to communicate with hive mates and recruit increasing numbers of workers to a good water source. A small wading pool could be relocated if necessary, but this is not an option with large pools. Usually, the bees are focused on their task and are not aggressive. Their presence may be disconcerting, but if not disturbed, they should pose no problem. Paper wasps will show up also.
Several water bugs will come plopping into pools because they figure any water is fair game. In addition, some unlucky non-aquatic insects may fall in and be unable to escape. These can be taken out with a dip net.
By Lee Townsend, Extension Entomologist