For Kas's question, these beetles seem interested in nothing but beans. And even those you probably have sealed up, so shouldn't be a problem. They are also picky about what type of beans. They breed freely in cups of black eyed peas, but just wouldn't in pinto beans.
I'll also relate my experience a couple years later on trapping bean beetles.
First of all, I don't need to trap them any more. I found a small, previously undiscovered, gap around a siphon tube coming out of the top glass in the back of the viv. That was how I was getting escapees. Plugged it up and now i have fewer roaming bean beetles than I do fruit flies... mostly the spiders get em or they die under the t5's.
Back when I did need to trap them, I tried motydesign's ahem design, and it did catch a fair number. But then my paper clip that i had hot glued to the bottom of the cup detached and the beans submerged to no longer be a lure to the beetles... and I continued to catch just as many. I noticed that the bean/cider trap caught only slightly fewer more than some empty cups near it were. Turns out that the beetles just like to get to as high a locality as they can, and will fall into or stick onto whatever you have up on top of the viv. Sticky paper or small cups of vinegar on top of my aquarium-hood style light fixture cut down on them significantly.
