Butterflies are probably the largest invertebrate herbivore group wiht representative data on hostplant associations.
Global compilations
These are mostly compilation of references in the literature
HOSTS - a Database of the World's Lepidopteran Hostplants, provided by the Natural History Museum of London, contains records for most lepidopteran families, including all butterfly families. Last update 18 Aug.2010
Lepidoptera and other life forms, developed by Markku Savela is a systematic compilation of information from literature references worldwide. Last update 2011.
Local, study sites databases
These are mostly based on (standardized) field observations in study sites
Caterpillars, developed by Lee Dyer, Jim Miller and Grant Gentry, provide field rearing records of caterpillars and their hostplants from Costa Rica, Ecuador, Brazil, and the United States. Last update 2002.
Inventory of the macrocaterpillar fauna and its food plants and parasitoids of Area de Conservación Guanacaste, reports the cumulative results of caterpillar, parasitoid and food plant inventory in the Area de Conservación Guanacaste in Costa Rica. Last update 2010.