Study of crossbred butterflies sheds new light on why sexual differences in fertility follow the pattern known as Haldane’s Rule.

We’re making life tough for insects – and not just by swatting them away with a newspaper.

The distribution of rare butterflies in Eastern Denmark has plummeted by 72% in just 26 years, researchers report.

For one species of butterfly, a vision gene's jump onto a sex chromosome explains why males and females see color differently.

When oleander aphids invade milkweed, monarch butterflies lay fewer eggs and caterpillars take longer to mature, a new study shows.

More and larger spots may help monarch butterflies survive their long migration. The spots may change airflow patterns around their wings.

Unseasonably warm and cold days can prolong the active period of moths and butterflies by nearly a month. "The results are not at all what we expected."

Scientists have discovered where the first butterflies originated and which plants they relied on for food.