A species of butterfly is poisonous to bird predators. Birds learn to avoid this species because when they attack and eat butterflies, the birds get sick. The butterfly species colonizes an island with no predators and over the next one million years gradually loses its toxicity. Which of the following is the most likely explanation for this?
1) The butterfly species evolves to have a different color pattern that mimics a non-toxic butterfly species.
2) The butterfly species develops a stronger immune system that prevents it from being affected by its own toxins.
3) The butterfly species undergoes genetic mutations that cause it to lose its toxic properties.
4) The butterfly species adapts to a different diet that does not require it to produce toxins.