The dog days

A distinct sound of late summer fills the air, as dog-day cicadas call from the tops of hardwood trees. On the ground, a familiar plant blooms with whorls of flowers that resemble a fireworks display. This plant, common milkweed, was obviously not named by the monarch butterfly. The monarch has adapted over time to use the milkweed for survival. Eggs are placed on the underside of its leaves and the caterpillars are born on their food source. The milkweed contains a toxic substance that monarchs have evolved to tolerate. The caterpillar and butterfly stages carry the substance in their own tissue, making them distasteful to predators. Thus, a plant that grows in "waste areas" like roadsides and sandpits and floodplains, a plant labeled a weed by humans, is vitally important to an insect we find beautiful.