Caterpillar Feud Behind Some Spicy Plants
Strong flavors from plant life range from mustard seed to the sharp, bitter taste of kale, and they came about as a result an evolutionary “arms race” between butterflies and certain plants.
To survive and reproduce, a species of plants called Brassicales (which includes cabbage) produced a chemical defense to repel the hungry caterpillar – and the chemical is what provides us with a variety of bitter and spicy flavors.
Brassicales developed compounds called glucosinolates over millions of years.
“Seeing the variation in the detoxification mechanisms among species and their gene copies gave us important evolutionary insights,” said Hanna Heidel-Fischer, one of the lead authors, who worked on the study at the Max Plank Institute for Chemical Ecology in Germany.
The team was able to examine genetic differences from nine Brassicales genomes across 14 families, enabling them to create a detailed map of the “family tree” of this species evolution. The map pointed the way to where changes in defense mechanisms occurred. In parallel, scientists examined the evolutionary “family tree” of several species of butterflies.
Comparisons between evolutionary benchmarks for Brassicales and butterflies revealed three significant evolutionary signposts over 80 million years, showing where plants developed chemical defenses and butterflies responded with adaptations and counter defenses.