Non-target effects of clothianidin on Danaus plexippus

A major focus in agricultural and natural systems has been the non-target effects of chemicals and pesticides to non-target, beneficial species. Neonicotinoids are widely used insecticides that attack the nervous system of exposed insects. One non-target species that is currently suffering from population declines and that have a very real opportunity to come into contact with neonicotinoids is Danus plexippus (monarch butterfly). We conducted a dose response study in the laboratory to determine lethal and sublethal doses of clothianidin against this charismatic caterpillar. We then quantified clothianidin content found on milkweed leaves adjacent to crop fields to assess whether developing monarch larvae would be exposed to lethal or sublethal doses of the insecticide under realistic conditions. Our work should assist in the future risk assessments of these widely used insecticides.