Bump

Many flying insects are attracted to lights at night. Moths and many different kinds of beetles will swarm a light burning outside after dark.

What kind of spider do you have?

What methods do you plan to use to capture the insects once they are attracted, and how will they be fed to the spiders? Are you trying to attract them to or near existing webs?

Please forgive me, but my first thought is rotten garbage to attract flies. I think the flies will find their way into the web without having to be caught. I'd love to see a picture of your spider. Flowers attract all kind of insects and so does water.