Monarchs rely on milkweed as the sole host plant for their caterpillars, and without it, their populations struggle to thrive ...

A Pennsylvania butterfly farmer says listing the monarch as a threatened species could do more harm than good.

Scientists have long known that milkweed cardenolides, which in most animals disable a vital sodium-potassium pump enzyme if they are absorbed into the blood, serve to make caterpillars and ...

Monarch caterpillars eat 200 times their weight in milkweed and can devour a whole leaf in less than 5 minutes. Monarch butterflies are poisonous to predators because of the chemicals in the milkweed ...

Milkweed is the only plant monarch caterpillars will eat, and the adult monarchs will lay their eggs on, according to the National Wildlife Federation. And with a declining habitat, it is ...

The chief causes of the decline include habitat destruction, drier and hotter climate due to climate change and insecticide ...

Just as monarchs famously prefer milkweed for food and egg-laying, swallowtail butterflies also have a preferred food as ...