If you’ve ever watched a butterfly work its way through a flower bed, you already know the short answer to what do butterflies eat and drink: nectar. But that’s only part of the story. Adult butterflies are surprisingly opportunistic feeders. They’ll lap up rotting fruit, sip from muddy puddles, drink tree sap, and yes – some species will land on your sweaty arm and drink from you. This guide covers the full picture, including what changes when they’re caterpillars and how you can support them in your own yard.
Key Takeaways
- Adult butterflies feed almost entirely on liquids, using a coiled, straw-like mouthpart called a proboscis to drink nectar, fruit juice, tree sap, and water.
- Beyond nectar, many species seek out mud puddles, rotting fruit, animal dung, and even sweat to get sodium and minerals that flowers don’t provide.
- Caterpillars eat solid food – mostly leaves from specific host plants – and have completely different dietary needs than adult butterflies.
- You can support butterflies in your garden by planting nectar-rich flowers, leaving out overripe fruit, and keeping a shallow water or mud source nearby.
How Butterflies Eat: The Proboscis
Adult butterflies don’t have mouths in any conventional sense. They have a proboscis – a long, flexible feeding tube that stays coiled up under their head like a watch spring when not in use. When a butterfly lands on a flower (or a piece of fruit, or your arm), it uncurls that tube and uses it to suck up liquid.
It works remarkably well for nectar, but it does mean butterflies are limited to liquid or semi-liquid food. They can’t chew. They can’t bite. If you’ve ever seen a butterfly sit on a piece of fruit for several minutes without seeming to do much, it’s drinking. The juice seeps up through the proboscis slowly.
One thing that surprises a lot of people: butterflies actually taste with their feet before they even bother uncoiling the proboscis. Sensory receptors on their tarsi (the foot segments) can detect sugars and salts on contact. If you want to go deeper on that, I wrote a full post on how butterflies taste with their feet – it’s genuinely one of the stranger things about them.
Flower Nectar – Their Primary Food Source
Nectar is the main thing butterflies eat, and it’s basically sugar water produced by flowers to attract pollinators. Different butterfly species have preferences for different flowers, but in general they’re drawn to blooms that are tubular or flat-topped (easier to land on and feed from), brightly colored, and strongly scented.
Nectar composition varies quite a bit between plant species. Some nectars are 20-25% sugar by concentration, while others sit closer to 10%. University of Maryland Extension notes that butterflies tend to be generalists when it comes to nectar sources, visiting a wide range of plants, unlike bees which can be more flower-specific. That flexibility is part of why planting a diverse garden does so much more for butterflies than a monoculture of one or two species.
If you’re interested in putting out a supplemental food source, homemade butterfly nectar is straightforward to make and can attract species to feeders when natural flowers are sparse. Worth trying if you have a feeder set up already.
Other Things Butterflies Eat and Drink
This is where it gets interesting. Nectar provides energy – mostly carbohydrates – but adult butterflies need more than sugar to survive and reproduce. They need sodium, amino acids, and other minerals that nectar alone doesn’t deliver in useful quantities. So they’ve evolved some creative ways to supplement their diet.
Mud Puddling
If you’ve ever seen a group of butterflies clustered on damp soil near a puddle or stream bank, you’ve witnessed what’s called “mud puddling.” They’re drinking the water, but more specifically they’re after the dissolved salts and minerals in it. Males do this far more often than females – the leading theory is that they’re loading up on sodium to pass along to females during mating, which can improve egg viability.
You can replicate this in your garden with a shallow dish of damp sand mixed with a small amount of sea salt or wood ash. It works surprisingly well as a butterfly attractant, especially on warm mornings.
Rotting Fruit
Fermenting fruit is legitimately a delicacy for many butterfly species. The sugars are more concentrated and broken down, the fruit is easier to feed from, and the fermentation process produces compounds that butterflies seem to actively seek out. Red Admirals, Question Marks, and various fritillaries are especially fond of rotting fruit.
The practical takeaway: don’t throw out overripe bananas, peaches, or apples. Cut them in half and set them on a plate in a sunny spot in your yard. You’ll have visitors within a day or two in the right season.
Tree Sap and Honeydew
Sap oozing from wounded trees is another liquid food source. It contains sugars, amino acids, and minerals, and certain species – particularly mourning cloaks and some satyrs – rely on it heavily, especially early in spring before many flowers are blooming. Aphid honeydew (the sticky substance aphids excrete onto plant leaves) is also consumed by some species.
Dung, Carrion, and Urine
This one tends to surprise people, but it makes sense once you understand what they’re after. Animal dung, decaying animal matter, and urine all contain concentrated sodium and amino acids. In tropical regions especially, you’ll see butterflies feeding on these sources regularly. In North America it’s less common but not rare – if you’ve ever had a butterfly land on you after exercise, it was almost certainly after the salt in your sweat.
There are even documented cases of butterflies drinking tears from the eyes of sleeping animals – a behavior called lachryphagous feeding. It’s well-documented in Southeast Asian species. Unusual, but the biology makes complete sense: tears are salty and mineral-rich.
All of this – the mud puddling, the fruit feeding, the sap – fits into the broader butterfly food chain that connects them to plants, soil chemistry, other insects, and the birds and predators that feed on them. It’s a more connected system than most people realize.
What Do Caterpillars Eat?
Caterpillars and adult butterflies eat completely different things, and this is one of the main reasons the two life stages don’t compete with each other for food.
Caterpillars eat leaves – almost exclusively. Most species are highly specialized about which plants they’ll accept. Monarch caterpillars famously eat only milkweed (genus Asclepias). Black swallowtail caterpillars stick to plants in the carrot family – dill, fennel, parsley. Spicebush swallowtail caterpillars feed on spicebush and sassafras. This isn’t just preference; caterpillars have evolved to process the specific compounds found in their host plants, including toxins that other insects can’t handle.
According to USDA Forest Service resources on pollinators, the relationship between caterpillars and host plants is so specific that butterfly populations are directly tied to the presence of those plants in the landscape. No host plant, no caterpillars, no butterflies – regardless of how many nectar flowers you’re growing.
This is worth keeping in mind if you want to do more than just attract passing adults. You need to plant for the whole life cycle. A garden full of coneflowers and zinnias will bring in adults to feed, but if there’s no milkweed, no fennel, no native host plants – you’re not supporting reproduction. For a thorough list of what to plant, the guide on butterfly food plants for your garden breaks it down by species.
How to Feed Butterflies in Your Garden
The best thing you can do is plant a mix of nectar flowers that bloom in sequence from spring through fall. A garden that only blooms in July is useful for a month; one that has something flowering from April through October supports butterflies through their full active season.
Native plants tend to outperform introduced ornamentals for butterfly feeding, partly because local species have evolved alongside local butterflies, and partly because native plants often produce nectar with higher concentrations of the specific compounds butterflies need. That said, some non-natives like lantana and butterfly bush are heavily visited – butterfly bush just has the drawback of not serving as a host plant for any caterpillar species.
A few practical additions that make a real difference:
- Set out overripe fruit on a platform feeder or flat rock – bananas and oranges work well.
- Keep a shallow dish of damp sand or soil in a sunny spot for mud puddling.
- Avoid pesticides – even “targeted” insecticides affect caterpillars and can reduce the adult populations you’re trying to attract.
- Leave some leaf litter and brush in sheltered spots for overwintering adults and pupae.
If you want to go further with supplemental feeding, nectar feeders designed for butterflies can pull in species that might not otherwise visit your yard, especially in areas where natural habitat is sparse.
Frequently Asked Questions
Do butterflies drink water?
Yes, butterflies do drink water, but rarely from open water sources the way birds do. They’re more likely to get water from nectar, wet soil, damp sand, or puddles. The mud puddling behavior is partly about water intake and partly about minerals dissolved in the water. A shallow dish of moist sand in your garden can serve as a reliable drinking spot.
Can butterflies eat solid food?
No. Adult butterflies have no chewing mouthparts – only the coiled proboscis used for drinking liquids. They are physically incapable of eating solid food. This changes completely when they’re caterpillars, which have strong mandibles and spend most of their time chewing leaves.
What is a butterfly’s favorite food?
Flower nectar is the primary food source for most adult butterflies, but “favorite” varies by species. Monarchs are partial to milkweed nectar and composites like goldenrod. Painted Ladies favor thistles. Many species that are commonly seen in gardens are generalists and will visit a wide range of flowers. If you want to attract specific species, matching your plantings to their known preferences is more effective than a generic wildflower mix.
Do butterflies eat fruit?
Many butterfly species feed on overripe or rotting fruit. The fermentation process breaks down the sugars and makes them easier to access through the proboscis. Species like Red Admirals, Mourning Cloaks, Question Marks, and various anglewings are particularly attracted to fermenting fruit. Setting out cut bananas or peaches in your garden is a reliable way to attract these species, especially later in the season when flowers are winding down.
Why do butterflies drink from mud puddles?
The behavior is called mud puddling, and it’s about minerals – primarily sodium – that butterflies can’t get in sufficient quantities from nectar alone. Males puddle more frequently than females, and studies suggest they transfer some of those minerals to females during mating, which can improve egg development. If you see a group of butterflies clustered at a wet spot on the ground, they’re almost certainly puddling.
What do monarch butterflies eat?
Adult monarchs primarily drink nectar from a wide variety of flowers, with a preference for composites like goldenrod, asters, and ironweed during their fall migration when they need to build fat reserves. Milkweed flowers are also a top nectar source for them. As caterpillars, monarchs eat only milkweed leaves – this is non-negotiable for the species, which is why milkweed loss across the landscape is such a significant conservation issue.
How long can a butterfly go without eating?
This depends on species, temperature, and activity level, but most adult butterflies can survive a few days without feeding under cool conditions where their metabolism slows. In warm weather with high activity, they need to feed more frequently to maintain energy. Some species that overwinter as adults – like mourning cloaks – can go months without eating while dormant in cold temperatures. During active periods, though, a butterfly that can’t find food will decline quickly.
