Cheryl Hayashi loves spiders, so much so that she says being asked to name a favorite is like asking a mother to pick which child she loves most. She challenges even arachnophobes to not crack a smile at jumping spiders' "teddy bear"-like cuteness. But it's not their good looks that attracts Hayashi, professor and vice chair of biology at University of California, Riverside, to spiders. It's their silk. Many spiders produce several different types of silk - some stronger, some stretchier - to