But population data for most of the 20,000 known butterfly species is scant to nonexistent, and recent surveys in the Amazon River Basin suggest that another 2,000 species have yet to be discovered. We have no idea how many butterfly species are lost as we say goodbye to an acre of rainforest with every heartbeat. But consider entomologist Edward O. Wilson's most conservative estimate that one year's rate of deforestation, approximately an area the size of Florida, obliterates some 27,000 species of plants and animals. Although other factors may be involved, the principal threat to butterflies, as with most wildlife, is the loss or alteration of habitat. Butterflies depend on the availability of nectar plants for the adults and host plants for the voracious caterpillars.
Most species are picky eaters, often dining exclusively on one species of plant.
As plants evolve into different species containing different chemical defenses to deter caterpillars, the butterflies counter by developing their new species, with the ability to sequester chemicals to use for their own defense. If the plant or habitat disappears so does the butterfly. This small butt effective organization has been active in preserving monarch wintering sites in California and has teamed up with The Nature Conservancy to protect endangered butterflies like the Oregon silverspot, the homerus swallowtail, and the bay checkerspot. Other projects around the world are in progress. Typically, however, insect conservation receives little presss or funding.