Cornucopia’s Take: Cry toxins are highly active protein toxins originally isolated from the bacterium Bacillus thuringiensis (Bt). They are genetically engineered into some GMO crops to perforate the gut membrane of insects that eat them. Poisoned pests stop eating and eventually die. Unfortunately, non-target animals, including monarch butterflies, swallowtail butterflies, lacewings, caddisflies, bees, water fleas, and mammals, are also susceptible to Cry toxins. Several influential studies used by the industry to show the safety of Cry toxins for non-target organisms are now in question. It appears the researched insects’ feed contained an inexplicably large dose of antibiotics, and antibiotics are known to inhibit the deadly action of Cry toxins.