Monarch butterflies are famous for their beautiful colors and their long migration patterns. They are also well known for being poisonous due to their consumption of the milkweed plant. A genetic mutation found in monarchs block the plant’s toxins while also allowing said toxic to accumulate in the insect. This mutation is found in 3 copies of a gene for the sodium-potassium pump and is critical to the monarch’s ability to tolerate the toxins of the milkweed found a group of researchers two years ago. This mutation, along with the monarch’s warning color has helped as a deterrent to hungry predators.
However, monarchs are not the only species that can tolerate
the milkweed’s toxins. This article shows that four different predators of
monarchs were recently discovered to have the same genetic mutation that
monarchs have. These organisms are the black-headed grosbeak, the eastern deer
mouse, a tiny wasp that parasitizes monarch eggs, and a nematode that parasitizes
monarch larvae. All four organisms have at least one or more copies of the
gene. The black-headed grosbeak and wasp has evolved single-nucleotide
mutations in their sodium pump gene in two of the three locations where
monarchs evolved the mutation. The eastern deer mouse and nematode have their
changes in all three locations. Noah Whiteman, evolutionary biologist and member
of the study, noted that this might be the first time we are seeing the same resistance
mutations that have been found in the second and third trophic levels that
evolved due to the second trophic level’s ability to feed on toxic plants. The team
suspects that there are other organism in the food chain that begins with the
milkweed that also have the same mutations found in monarchs.