We’re headed for the 4th generation of monarchs in the garden this summer. This next batch will be the ones to fly away to Mexico. The eggs have been laid by now and caterpillars across the state are hatching on what is left of our milkweed plants. By what’s left, I mean that which has escaped the Roundup, a decrease of approximately 58% since 1999. Half of all overwintering monarchs are Midwesterners, making the loss of their primary food source a crisis
There are 74 species of milkweed and 17 in Iowa.No doubt about it, these things could be called weeds. Once you get them going, they spread like the dickens from their roots. They’re poisonous too. (But the blooms smell wonderful!) The milk or latex holds cardenolides (cardiac glycosides), toxic chemicals, which make the monarchs taste bad to predators. Handle milkweed with care! However, like many natural products found in plants, these chemicals could be potential medicines both for heart failure and cancer. That’s what natural products chemistry is all about–finding things in nature that can benefit humanity. It also brings up WHY scientists dislike species loss. Besides being a tragedy from a biological standpoint and an aesthetic standpoint, it could be a tragedy from a natural products standpoint. More than butterflies will be wiped out if milkweed plants are lost forever.