Checking the backyard with a black light

Most Scorpions have a gene that makes them naturally glow under black light. Certain spiders, and other arthropods do as well. Many theories exist. Some hold that certain species hide amongst ultraviolet backgrounds like certain plants when hunting, so it helps blend in. Other evidence supports use in mating (like some spiders who use it to distinguish male/female) and it may even be used for other types of communication between a single species or even other species. While such an adaptation would seem an evolutionary disadvantage, its important to remember that it would not likely be so wide spread if it didn’t hold some type of advantage for a species.

It also holds true that some insects could possibly be able to see that far into the light spectrum so it could be used by them to avoid conflict with unintended prey. I happen to know from experience that certain spiders at my house are drawn to and spin webs around my security cameras presumably due to the infrared radiation they give off.