Computer artwork showing the effects of marijuana on the the web-making ability of Garden Spiders (Araneus diadematus). A normal orb web (left) is designed to capture prey. It is made of tough, non-sticky, radiating silk threads interconnected by an elastic, sticky spiral thread (hub). After construction, the spider will remove the central hub and remain there waiting for prey. A fresh web is usually constructed every 1-2 days and typically takes one hour to complete. A spider fed on marijuana-dosed flies produces an incomplete web (right) with many areas missing. Marijuana is derived from the dried leaves and flowering tops of the cannabis plant (Cannabis sativa) and contains the mood-altering drug tetrahydrocannabinol. Originally published in NASA Tech Briefs, April 1995.