Hello,

Thank you for your question and photo.

From the photo these insects appear to be some kind of wasp, likely solitary wasps in search of nectar and water. It has been a very hot dry summer, so some wasps resort to drinking pool water when they don't have any other sources of water. If they cannot fly away from the pool surface and accidentally get trapped, they are likely trying to escape drowning when they grab onto you. Then they likely feel threatened in some way (potentially from any handling or swatting) and thus sting whoever they are on.

These solitary wasps are considered beneficial insects since they are pollinators and sometimes predators of pest insects. They typically do not sting unless they feel threatened. Do you have any flowers around your pool? You could try providing the wasps with an alternative water source near any flowers or plants on your property, such as a shallow water dish with rocks on the bottom (to prevent pollinators from drowning). The water should be changed out frequently to prevent any mosquitos from reproducing in the water dish.

Talstar contains Bifenthrin which is a type of broad spectrum pesticide, so something to be aware of is Talstar can be highly toxic to pollinators like bees. Another thing to be aware of is research shows bug zappers unfortunately do not effectively control pest insects, instead bug zappers tend to kill beneficial insects like moths and other harmless arthropods. Please see these Extension articles for more information on bug zappers: 

• https://hortnews.extension.iastate.edu/1996/6-14-1996/bugzapper.html
• https://xerces.org/blog/to-protect-moths-turn-out-lights

I would remove and relocate any wasps that land in the pool with a net, cup, or similar tool. Most traps or pesticides will not result in a noticeable decline in activity since there are so many wasps in our environment. The best route is to provide alternative water resources and to identify any other attractants like nearby flowers or uncovered food or trash bins. Avoid handling or swatting at the wasps to reduce the chances of being stung.

For more information on bees, wasps, and other pollinators, please see this University of Maryland Extension article: https://extension.umd.edu/resource/pollinator-profiles.