From the Wikipedia entry for caffeine (edited for brevity):
Caffeine is a bitter, white crystalline purine… It is found in…a number of plants …, and helps to protect them against herbivores and from competition by preventing the germination of nearby seeds, as well as encouraging consumption by select animals such as honey bees. (https://en.wikipedia.org/wiki/Honey_bees).
Honeybees are drug-seeking insects?!? 8^D