Ladybugs eat gnats, mites, etc. They love soft-bodied insects, and enjoy eating wings. You can pick up 1500 in a 16oz cup for about $5-7.00 and they are worth it.
If god blessed your garden with a ladybug, be happy.
Ladybugs are excellent predators for aphids (thrips spider mites etc) if theirs ladybugs there wont be bad insects invading ur grow.
the more the merrier I say!!!!
U can actually lightly spray ladybugs with sugary pop (coke) or something similair, this makes their wings stick to their body for a few days (then repeat when u see one start flyin) this stops them from flying away and leaving ur grow area open to aphids!
Good luck!!