What if your host truly didn’t want you to visit? Found you intolerable, in fact, and didn’t want you to stay? You’d think that you’d be kicked out, but that isn’t the case with monarch butterflies and the common milkweed that supports their life cycle. Using striking visual imagery, evolutionary biologist Anurag Agrawal of Cornell University will speak about some of the natural history of monarchs and milkweed, the cultural importance of milkweed’s toxins, and the current predicament of monarch declines. The talk will be held in the Hunnewell Building of the Arnold Arboretum on Monday, December 4 at 7 pm. Dr. Agrawal is an award-winning scientist and educator, who has delved deeply into the coevolution of plants and animals. His book, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution, will be available for purchase and signing. Fee: Free Arboretum member and student, $10 nonmember. Register at my.arboretum.harvard.edu or call 617-384-5277.