I don't know a thing about spawning mosquitos. I find that any container of water has some in it this time of year so I scoop them up with a fish net, rinse them off with some clean water and drop them into the tank. In a tank that has many fish, they don't last long enough to do anything but take a few breaths through that snorkel of theirs.
What are you wanting to spawn, Mosquitos??? If so, there's nothing to do but set out something that will catch rain water and then wait a few days, you'll see lots of larvae.
Alex,I have cultures of paramecium,grindal worms,vinegar eels, microworms,Daphnia,and scuds.You know how to contact me ,let me know what you want and I will send it to you.
It's hot just about everywhere right now! If you're thinking about culturing Daphnia outside, put the container in partial shade. If you put it in direct sunlight, you're looking at failure.
I bought a great book on the subject of culturing your own foods, if you don't have anyone to teach you, want to know how to culture multiple live foods.
The book is "Culturing Live Foods by Michael R. Hellweg.
(Please note that I was just astonished by the information in this book and I don't know the author nor do I get any sort of money from recommending the book to you)
Just to tell you, stuff about keeping and raising Phytoplankton, Brine Shrimp, Algae, Worms (Graindel Worms, Tubifex worms + 2x more worms) Mullusks, Crustaceans, insects, fish. Well I think you get the idea.