Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

butterfly

insect
Also known as: Papilionoidea

News •

A butterfly that fooled scientists for 200 years finally reveals its secrets • Nov. 12, 2026, 5:49 AM ET (Science Daily)

butterfly, (superfamily Papilionoidea), any of numerous species of insects belonging to multiple families. Butterflies, along with the moths and the skippers, make up the insect order Lepidoptera. Butterflies are nearly worldwide in their distribution. Although their larvae may be destructive to certain plants, butterflies are major pollinators of the world’s wild and domesticated flowering plants, and all stages of their life cycle are important to local food webs. For more detailed coverage, see also Lepidoptera and list of butterflies and moths.

The wings, bodies, and legs, like those of moths, are covered with dustlike scales that come off when the animal is handled. Unlike moths, butterflies are active during the day and are usually brightly colored or strikingly patterned. Perhaps the most distinctive physical features of the butterfly are its club-tipped antennae and its habit of holding the wings vertically over the back when at rest. The lepidopteran life cycle has four stages: egg, larva (caterpillar), pupa (chrysalis), and adult (imago). The larvae and adults of most butterflies feed on plants, often only specific parts of specific types of plants.

Butterfly declines and conservation

A major study published in 2025 found that populations of butterflies across the United States are in serious decline, with total butterfly abundance having decreased by 22 percent from 2000 to 2020. The study found dramatic population drops for many individual species across all North American butterfly families: more than 100 species had declined by more than 50 percent, and more than 20 species had declined by more than 90 percent. Numerous other studies have documented regional declines throughout the world, indicating a widespread and serious problem. Pervasive pesticide use, including insecticides that directly kill or weaken butterflies and herbicides that kill the plants they rely on, habitat loss, and anthropogenic climate change are the major drivers of these losses. Access to pesticide-free habitat—wild areas as well as native plant gardens at homes, schools, and businesses—with abundant host plants for caterpillars and nectar plants for adults can help stabilize and support struggling butterfly populations.

Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters
Britannica Quiz
Animal Group Names

Major families

The butterfly families include:

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Rick Livingston.