for those who haven't seen one.......its just under the leaf in the photo. ( it has 3 separate dark masses in its body )
You know you have a serious infestation when the media surface is covered with tiny silky webs.
I don't worry because they are a food supply for my butterworts and I actually let them breed on a 2 week cycle. Every 2 weeks I get rid of most of the adults by placing 2 butterworts in the grow area. They stay there for about a week and then I remove them......and the cycle goes on.