I have a little 8 x 8 completely-screened-in "greenhouse." Aphids got in, and so I bought 500 lady bugs 2 days ago. I set them free to graze that evening. The bugs did a remarkable job. Within hours, I couldn't find an aphid anywhere, and my lady bugs were still all over my plants. The next am there were still plenty of lady bugs everywhere in the greenhouse. By the evening, I could only find one. Today, I couldn't find any. The greenhouse is enclosed with fine netting, so the bugs can't just fly away. I installed a small pipe as feeder/housing for the bugs, and put honey in it. No bugs in there, today. Any ideas on where they went?