Complex sentence: The leaves of this plant contain toxins that deter herbivorous animals--however some "Heliconius" butterfly larvae have evolved enzymes that break down these toxins, allowing them to specialize on this genus.
Split into simpler sentences: The leaves of this plant contain toxins that deter herbivorous animals. However, some "Heliconius" butterfly larvae have evolved enzymes that break down these toxins, allowing them to specialize on this genus.