The answer to this question is yes. They will zap or electrocute anything that touches the blue or purple lights.
If question is, “Do bug zappers work against mosquitoes?” Then the answer is, “NO!”.
Bug zappers rely on insects’ attraction to light. Have you ever noticed outside on a street light at night, all the bugs flying around? If you were to look closely at a zapper after it had been on a couple of nights, you would notice a whole lot of large insects fried to the outside safety grid. Upon closer look, none of these insects would be mosquitoes, they are moths. While you were looking at the fried moths, I bet you swatted several mosquitoes away from you. The skeeters are attracted to light, but are more attracted to you and me.
In all actuality, bug zappers are indiscriminate about what they zap. Some of these insects are harmless or may even be beneficial insects like bees or dragonflies. Your best bet is to hire a licensed, professional pest control company that specializes in mosquito control. They know where the mosquitoes are hiding, breeding, hatching and resting; thus, can eliminate them more effectively.