Cultivating crops, often as monocultures, weeding, applying fertilizer and if necessary herbicides or other protective treatments, followed by harvesting is one of the most familiar of human activities. Did you know, however, that agriculture has developed independently at least four times in human societies?
Even more remarkable than the repeated evolution of agriculture in humans, ants and termites have also each evolved agriculture independently, with the ant system having astonishing similarities to the workings of our own farms and fields. Ants and termites are not the only insects to maintain fungal gardens; beetles (most famously the ambrosia beetles), gall midges and wood wasps also cultivate fungi as a source of food. Further examples of agriculture can be found among herbivorous animals: algal fields are farmed by several species of damselfish, marine worms and snails, while dugongs regularly crop fields of seagrass.
A different type of agriculture-related convergence poses a considerable problem to human farmers: insects, fungi and weeds are constantly acquiring resistance to pesticides. Resistance to insecticides, fungicides or herbicides has occurred many times independently, each time apparently through only a few changes in the same key amino acids.