Over winter, insects suffer from the cold like everything else. In the natural world, they crawl into warm places like rotting logs, dead tree branches, etc to survive until spring. Without this, winter can easily wipe out the “good bugs” that help keep pests at bay. (I’m not sure how much of an issue this is in warm Sydney.)
I’ve read in books about the idea of an “insect hotel”, an artificially created home for a variety of insects. Then I came across Arup’s insect hotel, which won a recent government-led competition in London. It looks great:
Of course, we could just leave more of the natural environment intact, but that’s probably not an option in public parks and spaces.