This beautiful Monarch larva is munching on Common Milkweed, its only food. Milkweeds contain a cardiac glycoside in the leaves which the caterpillar stores in its body. The bright coloration is a warning to birds not to eat it. This picture was taken in late August, the butterfly that this caterpillar will become will migrate to Mexico and overwinter there. Most butterflies live only about a month. Monarchs that migrate delay their sexual maturity for several months. After mating in February and laying eggs in Texas, they will die. Reproduction is the "kiss of death" for these insects! A lot of children want to know if a caterpillar is a male or female, I tell them it isn't possible to tell the gender until it becomes a butterfly.