What Do Red Admiral Butterflies Eat? Nettle, Sap, and Fruit
What do Red Admiral butterflies eat? The answer changes completely between caterpillar and adult. Vanessa atalanta caterpillars feed almost exclusively on plants in the nettle family, while the adults skip flowers more often than you'd expect, favoring tree sap, rotting fruit, and even bird droppings over nectar. Both stages target foods most garden guides gloss over.
Egg to Adult: Four Stages, Two Very Different Diets
Red Admirals go through complete metamorphosis: egg, larva, pupa, adult. The diet split happens because the caterpillar's job is to build mass fast on one plant family, while the adult needs quick-burst sugars and minerals to fly, mate, and in many cases migrate.
- Egg: Females lay eggs singly on the tops of host-plant leaves rather than in clusters.
- Larva: Young caterpillars fold a leaf into a shelter and feed inside it; older caterpillars tie several leaves together with silk into a larger nest.
- Pupa: The caterpillar forms a chrysalis inside or near its leaf nest.
- Adult: The butterfly emerges and switches to a liquid diet of sap, fruit juice, and occasional nectar.
What Red Admiral Caterpillars Eat
Red Admiral caterpillars feed on plants in the nettle family, Urticaceae, which includes more than 50 plant genera worldwide. In North America and Europe, the best-known host is stinging nettle (Urtica dioica); other recorded hosts include false nettle (Boehmeria cylindrica) and Pennsylvania pellitory (Parietaria pensylvanica).
A patch of stinging nettle left standing, even a small one at the back of a yard, is usually enough to draw egg-laying females. Mowing it down in early summer removes an active generation of caterpillars along with it.
What Adult Red Admirals Eat
Adult Red Admirals are less dependent on flower nectar than most garden butterflies. They readily drink tree sap from wounds in bark, feed on rotting or fermenting fruit, and will visit animal dung and even carrion for fluid and salts. Overripe bananas, pears, or apples left out on a plate will often pull in more Red Admirals than a flowerbed will.
Flowers They Do Visit
When they do nectar, Red Admirals favor composite and clustered blooms: asters, butterfly bush (Buddleja), coneflower, and clover. Late-season asters matter most, since they're often the last significant nectar source before the butterflies head south or go into hibernation.
Puddling and Wicking
Red Admirals also drink from moist water sources rich in minerals and electrolytes, a behavior researchers call puddling or wicking. This lets them pick up sodium that a sugar-heavy sap-and-fruit diet doesn't supply on its own. In many butterfly species, including Red Admirals, males puddle more often than females, and some of the sodium they collect can be passed to females during mating.
Seasonal Shifts in Feeding
Spring
Adults that overwintered as hibernating adults, or that arrive from farther south, emerge before most flowers bloom. Sap flows and early bloomers like dandelion fill the gap until the rest of the garden catches up.
Summer
This is when Red Admiral numbers peak in most of their range. Males stake out sunlit territories, often on ridgelines or along tree lines, and will chase off rival males and other butterflies from a favored perch.
Fall
As flowers thin out, fallen fruit and late asters carry adults through the final weeks before cold weather. Northern populations move south toward warmer states, while others enter hibernation in sheltered spots like woodpiles or evergreen cover.
Building a Yard That Feeds Both Stages
Because caterpillar and adult needs are so different, a Red Admiral-friendly yard needs more than a nectar bed:
- Leave some nettle standing: A single unmown patch supports an entire generation of caterpillars.
- Put out overripe fruit: Sliced banana or apple on a dish or feeder tray draws adults reliably, especially in late summer.
- Plant late-season bloomers: Asters and other fall flowers matter more here than early-summer color.
- Skip the pesticides: Even organic sprays applied to nettle patches will kill caterpillars along with any target pest.
Why the Diet Matters for Conservation
Habitat loss and pesticide drift affect Red Admirals less through nectar-flower loss than through the disappearance of host-plant patches and unsprayed fruit-fall zones. A weedy nettle corner and a bowl of rotting fruit do more for this species than a formal butterfly garden built around flowers alone.
