A great case study by Tamsin Woolley-Barker:
We need to pull this system of disparate parts together. The sea sponge comes to mind: a porous bag of tissues inside a tough exterior tube. Water draws nutrients through the tube, to be filtered for consumption by the porous bag. Or spider webs, passively filtering insects while the breeze passes through. We can use these strategies to keep insects out, while drawing ethylene in. Our plan emerges: a mesh bag, surrounded by a waxy canvas tube, is tied over the developing penca. Continued at http://bioinspiredink.blogspot.com