[mcaterino]

These beetles can feed on just about anything in the cucurbit family, any squashes or melons, as well as cucumbers. There are a number of these that grow wild, and may be weedy even in abandoned lots. So there are likely other host plants closer than you suspect. They do have excellent 'noses' (antennae), too, as RWebb says, and can find their favored plants from a fair distance.

Mike