I’m fairly certain the common, small “gnats” I see from time to time in my hour are the common fruit fly, Drosophila melanogaster. I read that overwatering indoor plants can cause a fly problem. So, I’m watering my plants less now.
These particular flies, (if they are D. melanogaster), lay 500 eggs at a time, which go through larval and pupal stages to emerge as adult flies in about two weeks. Adults are capable of breeding within 48 hours of maturation, and they live several weeks, breeding more than once during this time.
No one knows for sure how many species of insects exist in the world or in any one state. I’ve read estimates that there are 20 to 30 million species of insects worldwide. This is just Class Insecta, not the whole phylum of Arthropoda.
I was shocked to learn more than 80 percent of all living things on the planet are classified as arthropods. Researchers estimate that in a typical forest acre there may be 425 million living arthropods—with Arachnids being the most abundant of these.
In North America, there are an estimated 920,000 named species of insects. Florida is estimated to have more than 15,000 species—but, I think this is a very low estimate.