The Invisible World of Butterflies
Some of the best parts of a butterfly are too small to see. At Lucy’s station, you look closer.
Reference photos of museum specimens, credited under each topic and on the credits page.
What you’ll discover at the field station of Lucy Garcia Salik, PhD, our scientific lead: real pinned specimens, microscopes, and the questions she gets asked most. The topics below are hers. The short explanations under each are ours, for reading at home.
Morphology of Scales
Butterfly wings are covered in tiny overlapping scales, like roof tiles. Some scales get their color from pigment. Others shine because of their shape.
- Pigmented vs. structural scales
- Iridescence and light diffraction
- Functions: camouflage, thermoregulation, sexual signaling
Dig deeper
Lepidoptera, the scientific name for butterflies and moths, means "scale wing." Pigment colors come from chemicals inside a scale that absorb some colors of light; structural colors come from microscopic ridges and layers on the scale that make light waves interfere and diffract. That is why the blue of a male Morpho does not come from a blue pigment, and why such colors can shimmer and shift as the viewing angle changes (iridescence). Wing colors do several jobs, including camouflage, absorbing sunlight for warmth, and sending signals to mates.
Reference photo
Photo: The Trustees of the Natural History Museum, London (photo: Geoff Martin) · Natural History Museum, London · CC BY 4.0 (cropped and resized). Not the specimen in Lucy’s drawer.
Morpho helenor · Open its tray
Lucy’s microscope view of a butterfly wing: overlapping scales, like shingles on a roof.
Photos: Lucy Garcia Salik, PhD
Wing Venation
Veins are thin tubes that hold a wing's shape. Scientists clear away the color so the veins show, then use their pattern to tell butterfly families apart.
- Demonstration using prepared diafanized wings
Dig deeper
Wing veins strengthen the thin wing membrane, and in a living butterfly they carry hemolymph, air tubes and nerves, so the wing is living tissue. Scales hide the veins, so specialists clear the wing (diafanization), for example by bleaching it or by wetting the scales so light shines through, to reveal the vein pattern. Because vein patterns differ between groups, they have long been one of the main features used to identify butterfly and moth families.
Reference photo
Photo: Digital Image: Yale Peabody Museum; photo by Paul Shamble 2011 · Yale Peabody Museum of Natural History (Entomology) · CC0 1.0 (cropped and resized). Not the specimen in Lucy’s drawer.
Haetera piera · Open its tray
Research notes
From published sources, not from Lucy’s catalog. Each note lists where it came from.
Overview
A butterfly wing is a very thin sheet held up by a network of narrow tubes called veins. The veins brace the sheet and help it keep its shape. In a living butterfly the veins also work as channels. Insect blood (hemolymph) moves through them, along with tiny air tubes and nerves. That means the wing is living tissue, not just a dry flap.
What sets them apart
Different groups of butterflies and moths have different vein patterns. Because of this, the layout of the veins is one of the main features specialists use to tell families apart. When they compare two specimens, they look at how the veins run and branch across the forewing and hindwing.
Internal Sclerotized Structures
Inside a butterfly are some tiny hard parts. Scientists study them under a microscope to tell apart species that look almost the same.
- Demonstration using prepared dissections
Dig deeper
"Sclerotized" means hardened: parts of an insect's body covering are toughened by a natural process called sclerotization. Some of these hard internal structures, especially the reproductive parts, have shapes that differ from one species to the next. Scientists soften away the surrounding tissue with a chemical solution, clean and stain the hard parts, and examine them under a microscope. For moths and butterflies that look nearly identical from the outside, this is often the best, or the only, way to tell species apart.
Reference photo
Photo: The Trustees of the Natural History Museum, London · Natural History Museum, London · CC BY 4.0 (rotated, cropped and resized). Not the specimen in Lucy’s drawer.
Heliconius hecale · Open its tray
Biological Curiosities
Butterfly bodies are full of surprises. They breathe through holes in their sides, taste with their feet, and see colors we can't.
Dig deeper
As insects, butterflies are built very differently from us: a hard outer skeleton instead of bones, air tubes instead of lungs, and a blood-like fluid (hemolymph) that does not carry oxygen. Their senses suit their way of life. Taste sensors on the feet help females find the right plants for their caterpillars, and many species can see ultraviolet patterns on each other's wings.
Reference photo
Photo: Yale Peabody Museum; photo by Paul Shamble 2011 · Yale Peabody Museum of Natural History (via GBIF) · CC0 1.0 (cropped and resized). Not the specimen in Lucy’s drawer.
Danaus gilippus · Open its tray
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Respiration through spiracles
They breathe through tiny holes along their sides called spiracles.
Dig deeper
Insects have no lungs. Air enters through spiracles on the sides of the body and travels through a network of branching tubes (tracheae) that carry oxygen directly to the body's cells.
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Taste receptors on the legs
Butterflies can taste with their feet.
Dig deeper
Their legs carry taste sensors (chemoreceptors). When a female lands on a leaf, she can taste whether it is the right plant for her caterpillars before she lays eggs.
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Vision in UV spectrum
Many butterflies can see ultraviolet light, a color our eyes can't see.
Dig deeper
Many butterflies have eye cells sensitive to ultraviolet. Their wings can carry UV patterns that look quite different from what we see, and in many species these patterns help butterflies recognize mates of their own kind.
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Longevity differences among species
Some butterflies live only a few weeks as adults. Others can live for months.
Dig deeper
Summer monarchs live a few weeks as adults, but the generation that migrates in fall can live up to about eight months. Longwing butterflies (Heliconius), which also feed on pollen, can live around six months. Adult giant silk moths (Saturniidae) cannot eat at all and live only a short time.
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Migration patterns
Many monarchs in eastern North America fly thousands of miles to spend the winter in Mexico.
Dig deeper
In eastern North America, several summer generations of monarchs breed as they move north. The last generation of the year flies thousands of miles south to wintering sites in Mexico, and the trip back north takes several generations.
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Hemolymph ("blood") and open circulatory system
Their "blood" isn't red, and it sloshes around inside them instead of flowing through blood vessels.
Dig deeper
Insects have an open circulatory system: hemolymph bathes the organs directly, and a long tube-shaped heart along the back pushes it forward. Hemolymph carries nutrients and hormones but not oxygen; the air tubes do that job.
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Exoskeleton vs. internal skeleton
A butterfly wears its skeleton on the outside, like a suit of armor.
Dig deeper
Instead of bones inside, insects have an exoskeleton built largely of chitin. It protects the body, helps keep it from drying out, and gives muscles places to attach on the inside. Because it can't stretch, a caterpillar has to molt (shed it) in order to grow.
Research notes
From published sources, not from Lucy’s catalog. Each note lists where it came from.
Overview
Butterflies are insects, and their bodies work on a very different plan from ours. The hard skeleton is a covering on the outside of the body, not a set of bones inside it. They have no lungs. Air comes in through small openings along the sides of the body, and a branching system of air tubes carries it to the cells. Their blood-like fluid, called hemolymph, moves loosely around inside the body. It does not carry oxygen, because the air tubes do that job.
What sets them apart
Breathing: openings called spiracles sit along the sides of the body. Behind them, tubes called tracheae split into smaller and smaller branches that bring air right up to the cells. Circulation: insects have an open system. Hemolymph does not run through blood vessels. Instead it washes around the organs, and a long, tube-shaped heart along the back pushes it toward the front of the body. Hemolymph carries nutrients and hormones, but oxygen travels separately through the air tubes. Outer skeleton: the exoskeleton is made largely of chitin. It protects the body, helps keep it from losing water, and gives muscles places to attach on its inner side. An insect grows by molting, which means breaking free of the old exoskeleton and expanding a new one.
Common mix-ups
It's easy to assume an insect's 'blood' works just like ours. Hemolymph shares many of the same jobs, such as moving nutrients and hormones around the body. But it does not carry oxygen, and it is not red. It's also easy to picture insects breathing with lungs. They have none. Air enters through spiracles and travels through a system of tubes that is separate from the circulatory system.
Butterfly vs. Moth Differences
Butterflies and moths are close cousins. Most butterflies have clubbed antennae and fly by day, and most moths don't. But there are exceptions.
Dig deeper
Butterflies and moths belong to the same insect order, Lepidoptera, and no single feature separates them perfectly. Antennae, time of activity and body shape are useful clues that work most of the time, but each one has exceptions, so experts look at several features together.
Reference photo
Photo: Digital Image: Yale Peabody Museum; photo by Brendan Fitzpatick 2009 · Yale Peabody Museum of Natural History (Entomology) · CC0 1.0 (cropped and resized). Not the specimen in Lucy’s drawer.
Attacus atlas · Open its tray
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Antennae shape
Butterfly antennae end in little clubs. Moth antennae are usually thread-like or feathery.
Dig deeper
Most butterflies have a thickened club at the antenna tip (in skippers it often ends in a hook), while most moths have thread-like or feathery antennae. A few moths, such as sun moths (Castniidae), have clubbed antennae too. Feathery antennae give moths extra surface for detecting scents, which males use to find females.
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Activity period (diurnal vs. nocturnal)
Most butterflies fly by day and most moths at night, but some moths fly by day.
Dig deeper
Butterflies are usually active in daylight (diurnal), and most moths are active at dusk or at night (nocturnal). It's only a tendency: many moths fly by day, including sun moths (Castniidae) and some uraniid moths.
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Body morphology
Moths often have thicker, fuzzier-looking bodies than butterflies.
Dig deeper
Many moths have stout bodies with a thick coat of scales that makes them look furry, while butterflies tend to be slimmer. This is a tendency, not a rule: skippers, for example, have stout bodies like a moth's.
Research notes
From published sources, not from Lucy’s catalog. Each note lists where it came from.
Overview
Butterflies and moths are not two separate kinds of insect. Both belong to one insect order, Lepidoptera, so they are close relatives. No single trait divides them cleanly. Checking the antennae, the time of day the insect is active and its body build will usually point to the right answer. Each of these clues has exceptions, though, so experts weigh several features together instead of relying on one.
What sets them apart
Antennae: In most butterflies, each antenna gets thicker at the tip, forming a knob or club. In skippers the tip may instead bend into a small hook. Most moths have antennae that are plain and thread-like or branched like a feather, with no club. Feathery antennae have more surface for picking up smells, and male moths use them to track down females. Activity: Butterflies are mostly out in daylight (diurnal). Most moths are active in the evening or after dark (nocturnal). Body: Moths often look heavier, and a dense coat of scales makes them seem fuzzy. Butterflies are usually slimmer and smoother. These are general patterns, not strict rules.
Common mix-ups
A common mistake is to treat any one clue as a perfect test. Clubbed antennae do not always mean butterfly: sun moths (family Castniidae) are moths, yet their antennae end in clubs. Flying by day does not always mean butterfly either. Many moths are active in daylight, including sun moths and some moths in the uraniid family. Body shape is also only a tendency, and some butterflies are stouter than the usual picture suggests. The safest approach is to look at several features together and accept that some insects will not fit the usual pattern.
Butterfly Family Identification and Comparison
Scientists sort butterflies into families. They check clues like wing veins, legs, wing shape and color.
- Identification of families and species
- Comparison of Papilionidae, Nymphalidae, Pieridae, etc.
Dig deeper
Identifying a family means combining several features: the pattern of wing veins, the structure of the legs (for example, whether the front legs are full-sized or reduced), and typical wing shapes and colors. The drawer's moth families make a useful comparison; giant silk moths (Saturniidae), for instance, are large moths with thick, hairy bodies, and males usually have bigger feathery antennae than females.
Reference photo
Photo: Yale Peabody Museum; photo by Aimee Burg 2011 · Yale Peabody Museum of Natural History (via GBIF) · CC0 1.0 (cropped and resized). Not the specimen in Lucy’s drawer.
Graphium weiskei · Open its tray
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- LycaenidaeBlues, coppers and hairstreaks: small butterflies, often with shiny blue or coppery upper wings.In the drawer
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Activities
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Children’s Activity: Coloring Station
- Butterfly drawing and coloring
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Microscopy Live Projection
- Real-time visualization of wing scales
- Iridescence demonstration
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Wing Venation (Diafanization)
- Prepared transparent wings
- Identification of veins
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Internal Sclerotized Structures
- Prepared dissections
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Public Microscopy Station
- Visitors explore wing scales, eyes, antennae, internal sclerotized structures
Activities happen at the pop-up itself.
Questions to bring
Pick up to three questions. Ask Lucy when you visit.
Your picks are saved on this device only, in your Field Journal.
- How butterflies breathe
- How they taste
- How they see UV colors
- Why some species live longer
- Migration behavior
- Wing color formation
- Hemolymph vs. blood
- Exoskeleton structure
- Differences between butterflies and moths
- Difference between males and females
- Species identification
My questions for Lucy
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