Natures wonders: monarch caterpillars store toxins (Introduction)

by David Turell , Thursday, November 05, 2015, 14:46 (3304 days ago) @ David Turell

From the milkweed, they pick up poisonous compounds to ward off predators but the toxins are harmless to them:-http://www.the-scientist.com/?articles.view/articleNo/44410/title/Butterflies-Weaponize-Milkweed-Toxins/ -"Monarch butterfly caterpillars have evolved the ability to store toxins known as cardenolides, obtained from their milkweed diet, specifically to make themselves poisonous to birds, as has at least one other species of milkweed-munching caterpillar, according to a study published Wednesday (November 4) in Proceedings of the Royal Society B.-***-"If the cardenolide-resistant enzymes don't help the caterpillars eat more milkweed, Agrawal and Petschenka reasoned, they must exist for another reason, such as predator defense. The researchers measured levels of cardenolides in the bodies of the three caterpillar species and found that, while common crows don't store any, both monarchs and queens store the toxic compounds, with monarchs storing concentrations about twice as high as queens. Such storage turns these species into poisonous prey, effectively warding off birds and other predators."-Comment: From an evolutionary standpoint, the caterpillars had to first develop enzymes to protect themselves, then the defense mechanism could work. These are multiple complex steps, accomplished stepwise, but how? You know my answer.