According to Monarch Watch, the citizen scientist program that monitors the Monarch butterfly migration and started the tagging program, monarch caterpillars consume 200x their birthweight in milkweed leaves in about a two-week period. Commercial butterfly breeders suggest that a single caterpillar can easily decimate an entire one-gallon milkweed plant--175 leaves per caterpillar. Of course, it depends on the milkweed you supply. Our native Texas milkweed, Antelope Horns, Asclepias asperula, is much heftier than the Tropical Milkweed, Asclepias curassavica, found in nuseries right now--like a beef steak compared to lettuce. Yet, when the Monarchs are flying, any milkweed is better than none. Sound impossible? Watch the video.