Biology Nicotiana

There are many species of tobacco, which are encompassed by the genus of herbs Nicotiana. It is part of the nightshade family (Solanaceae) indigenous to North and South America, Australia, south west Africa and the South Pacific. Many plants contain nicotine, a powerful neurotoxin, that is particularly harmful to insects. However, tobaccos contain a higher concentration of nicotine than most other plants. Unlike many other Solanaceae, they do not contain tropane alkaloids, which are often poisonous to humans and other animals.

Despite containing enough nicotine and other compounds such as germacrene and anabasine and other piperidine alkaloids (varying between species) to deter most herbivores, a number of such animals have evolved the ability to feed on Nicotiana species without being harmed. Nonetheless, tobacco is unpalatable to many species, and therefore some tobacco plants (chiefly tree tobacco, N. glauca) have become established as invasive weeds in some places.