Yellow butterflies add a touch of cheerful color to North Carolina’s diverse butterfly population. This guide introduces you to the species you can find across the state. Learn about the different species of yellow butterflies, their unique behaviors, and where to observe them in the wild.

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Yellow Butterflies Found In North Carolina

Clouded Sulphur Butterfly

Phylum

Arthropoda

Class

Insecta

Order

Lepidoptera

Family

Pieridae

Genus

Colias

Species

C. philodice

Binomial Name

Colias philodice

  • Clouded Sulphur butterflies love alfalfa, and can become serious pests when its population gets too dense in a given area.
  • Another common name for the these yellow butterflies is “Common Sulphur” (Pyle 1981).
    • The word “sulphur” can be spelled either with a “ph” or “f”, as in “sulfur”. The International Union of Pure and Applied Chemistry (IUPAC) made “sulfur” the preferred spelling in 1990, but many books and field guides still use the old spelling. Either one can be considered correct spelling for this butterfly’s common name.
  • Clouded Sulphur butterflies (Colias philodice) sometimes mate with Orange Sulphur butterflies (Colias eurytheme) (Opler and Malikul 1992).
    • These two yellow butterflies look almost identical and their ranges and food plants overlap. In fact, it can be very hard for humans to tell the two types of yellow butterflies apart in real life.
    • The butterflies themselves don’t really have this problem. Male Clouded Sulphur butterflies produce special chemicals called pheromones. Orange Sulphurs don’t make the same chemicals (Grula et al. 1980). Females of each species identify males of their own species by how the males smell.

Clouded Sulphur Butterfly Images

How To Identify Clouded Sulphur Butterflies

  • Wingspan: 1.4 – 2.0 inches (3.6 – 5.0 cm)
  • Clouded Sulphur butterflies can be hard to identify for two reasons:
    • Males and females are sexually dimorphic; they look different from each other.
    • Adults are “seasonally variable”; their appearance varies slightly with temperature:
      • Spring and fall adults are small and greenish-yellow (Pyle 1981).
      • Summer adults are large and bright yellow butterflies.
  • Above:
    • Males have bright sulphur-yellow wings with sharply defined, solid black borders.
    • Females can be either yellow or white with yellow-spotted black borders.
    • Both sexes have a black wing spot on their forewings.
    • Hind wings have an orange spot in the center.
  • Below:
    • Green-yellow overall with a faint row of dark spots.
    • Male forewings show a single black spot.
    • Female forewings may have a small, pinkish wing spot.
    • Hind wings have two spots each; one large and one small. Both spots are silvery and surrounded by thin, red rims.
    • Pink wing fringe.
    • Hind wings have a widely spaced single row of tiny brown spots.
  • Clouded Sulphurs almost always close their wings when they land.

How to Find Clouded Sulphur Butterflies

  • Flight Season: Adults fly between late March and mid-November in North Carolina.
    • Female Clouded Sulphur butterflies lay eggs throughout this time so many broods develop over the summer.
  • Look for Clouded Sulphur butterflies anywhere lots of flowers bloom. You can find these yellow butterflies in waste lots, meadows, farm fields, and along roadsides.
    • They especially love sunny areas where clovers, vetch, and other legumes grow.
    • Favorite nectar sources include:
      • Blue Vetch (Vicia cracca)
      • Wild Lupine (Lupinus perenis)
      • White Sweet Clover (Melitotus alba)
      • Red Clover (Trifolium pratense)

How to Identify Clouded Sulphur Eggs, Caterpillars, And Chrysalises

Eggs

  • Female Clouded Sulphur butterflies lay their eggs one at a time on clover plants (Pea family Fabaceae).
  • Clouded Sulphur butterfly eggs are pale, yellow-green when first laid but turn red after a day or two, then gray before they hatch (Wagner 2005).

Caterpillars

  • Clouded Sulphur caterpillars are bluish-green and about 1.4 inches (3.5cm) long (Wagner 2005). A single thin, cream-colored stripe runs lengthwise down their sides. The stripe may include pink or red sections and be edged in black or dark green.
  • Look for Clouded Sulphur caterpillars on plants in the Pea family (Fabaceae) especially:
    • White Sweet Clover (Melitotus alba)
    • Red Clover (Trifolium pratense)
    • Dutch Clover (Trifolium repens).
  • This species feeds on Alfalfa (Medicago sativa), which both grows as a wildflower in North Carolina after it escaped cultivation (Daniels 2003) and as a human food crop. Clouded Sulphur caterpillars can become real pests to alfalfa farmers.

Chrysalises

  • Chrysalises are green.
  • Individual Clouded Sulphurs survive North Carolina’s winters as pupae. Their leathery, waterproof chrysalises protect them from freezing to death.
    • Once spring arrives, the pupae emerge as adults and start to breed.
    • Mild temperatures in mid-winter sometimes trick them into emerging too soon (Opler and Malikul 1992).

Cloudless Sulphur Butterfly

Phylum

Arthropoda

Class

Insecta

Order

Lepidoptera

Family

Pieridae

Genus

Phoebis

Species

P. sennae

Binomial Name

Phoebis sennae

  • Also called “Cloudless Giant Sulphurs”.
  • Cloudless Sulphur butterflies have unusually long probosces, the coiled, tubular mouthpart with which butterflies siphon flower nectar for food.
    • For example, the probosces of P. sennae are nearly 0.4 inches (1 cm) longer than those of a Brush-footed butterfly species, the Gulf Fritillary Butterfly (Agraulis vanillae).
    • This allows Cloudless Sulphurs to access nectar from flowers whose nectaries are so deep they can’t be reached by other butterflies (Daniels 2003).
    • Why is this so important?
      • Lipids (otherwise known as fat) are an important source of energy for insects.
      • Cloudless Sulphurs have less energy stored than Gulf Fritillaries.
        • Lipids make up only 6% of the mass of a newly emerged adult Cloudless Sulphur Butterfly. In comparison, a Gulf Fritillary’s mass is 13-16% lipid (May 1992).
      • All things being equal, a Cloudless Sulphur butterfly will starve to death faster than a Gulf Fritillary butterfly.
      • But, thanks to their extra-long probosces, Cloudless Sulphur butterflies can feed from a greater variety of flowers than can Gulf Fritillaries, and can feed with greater efficiency; more than four times the efficiency of Gulf Fritillaries (May 1992).
  • The word “sulphur” can be spelled either with a “ph” or “f”, as in “sulfur”. The International Union of Pure and Applied Chemistry (IUPAC) made “sulfur” the preferred spelling in 1990, but many books and field guides still use the old spelling. Either one can be considered correct spelling for this butterfly’s common name.

Cloudless Sulphur Butterfly Images

How To Identify Cloudless Sulphur Butterflies

  • Wingspan: 2.1 – 2.75 inches (5.3 – 7 cm).
  • These large yellow butterflies perch with their wings tightly closed.
  • Above:
    • Both forewings and hind wings are clear, bright sulphur yellow.
      • Males are brighter yellow than females.
    • Male forewings are unbroken yellow.
    • Female forewings each have a single, small, brown-rimmed wing spot and a thin, broken brown band along the wing edge.
  • Below:
    • Appearance varies by sex (“sexually dimorphic”)
    • Male Cloudless Sulphur butterflies:
      • Have a single pale spot on their forewings and hind wings.
      • Are more uniformly colored than females; wings range in color from tan to yellow.
    • Female Cloudless Sulphur butterflies:
      • Are brighter in color than males.
      • Mottled, with scattered dark marks.
      • Wings range in color from greenish-white to pinkish-orange to bright yellow.
      • Can have multiple small silver-white spots on both forewings and hind wings.

How to Find Cloudless Sulphur Butterflies

  • Flight Season: Early March and late November in North Carolina.
    • Cloudless Sulphur females lay eggs throughout this time so many broods develop over the summer.
  • Cloudless Sulphur butterflies live year-round in Florida and the southernmost states.
    • As temperatures rise in the spring, millions of these large, bright yellow insects venture north, reaching North Carolina in early spring, and sometimes making it as far north as Maine and southern Canada.
    • However, the northernmost butterflies die out in the fall; they don’t travel back south (Pyle 1981).
    • More southern populations travel south in fall to overwinter (Daniels 2003).
  • Cloudless Sulphur Butterflies seem to be especially fond of puddling and can often be seen grouped together around mud puddles and disturbed ground.
  • Look for Cloudless Sulphur Butterflies in any kind of open space with lots of blooming flowers and sunlight, like meadows, along roadsides, and in home gardens.
    • These yellow butterflies favor lantana, bougainvillea, Turk’s Cap (Lilium superbum), and hibiscus (Opler 1994).

How to Identify Cloudless Sulphur Eggs, Caterpillars, And Chrysalises

Eggs

  • Female Cloudless Sulphur butterflies lay tiny pitcher-shaped eggs that start out pale and turn pale orange over time (Pyle 1981). They lay eggs one at a time on the leaves of a host plant (Daniels 2003).

Caterpillars

  • When young, Cloudless Sulphur caterpillars are yellowish-green with a thick yellow side stripe.
  • Green heads sprinkled with tiny black spots.
  • Body segments are covered in tiny black spots ringed in pale blue.
  • As the caterpillars grow and age towards metamorphosis, their bodies turn bright yellow with widely spaced black side-to-side stripes (Glassberg 2002)
  • During the day, Cloudless Sulphur caterpillars hide within leaf shelters they construct by pulling leaves together with silk (Pyle 1981).
  • Look for Cloudless Sulphur caterpillars on plants in the Pea family (Fabaceae) like:
    • Littleleaf Sensitive Briar (Mimosa microphylla)
    • Partridge Pea (Chamaecrista cinerea)
    • Red Clover (Trifolium pratense)
    • Dutch Clover (Trifolium repens)
    • Wild Senna (Senna hebecarpa)
    • Java-bean (Senna obtusifolia)

Chrysalises

  • Chrysalises are elongated, pointed at the ends, and bulge in the middle. They are pink or green with yellow or green stripes (Pyle 1981).

Eastern Tiger Swallowtail Butterfly

Phylum

Arthropoda

Class

Insecta

Order

Lepidoptera

Family

Papilionidae (Swallowtail and Parnassian Butterflies)

Genus

Papilio

Species

P. glaucus

Binomial Name

Papilio glaucus

  • Females come in two forms: a yellow morph and a dark morph.
    • Dark form females resemble a cousin swallowtail species, the Pipevine Swallowtail (Battus philenor).
      • Pipevine Swallowtail butterflies are notoriously toxic to predators; most butterfly predators actively avoid attacking them.
      • Dark-morph Eastern Tiger Swallowtail butterflies likely gain protection from predators by mimicking their smaller, dangerous cousin.
  • Eastern Tiger Swallowtail caterpillars feed on tree species whose leaves contain toxic compounds but remain entirely edible to their predators. Rather than incorporate the toxins into their body tissues, the caterpillars excrete the compounds (Frankfater et al. 2005).

Eastern Tiger Swallowtail Butterfly Images

How To Identify Eastern Tiger Swallowtail Butterflies

  • Wingspan: 3.0 – 5.5 inches (7.6 – 14 cm)
  • Eastern Tiger Swallowtail butterflies come in three forms:
    • Males
    • Yellow form females
    • Dark form females
  • Above:
    • Males and yellow form females are yellow butterflies and have black tiger stripes on their forewings.
    • Dark form females have dark forewings that may or may not show faint black tiger stripes.
    • Both yellow and black form females have more blue scaling on their wings than males.
  • Below:
    • Males and yellow form females have black tiger stripes on their forewings.
    • Dark form females have dark forewings that may or may not show faint black tiger stripes.
  • Each hind wing has a long tail.

How To Find Eastern Tiger Swallowtail Butterflies

  • Eastern Tiger Swallowtail butterflies are among the easiest species to spot in the wild thanks to their large size, abundance, and preference for nectar from a huge variety of wild and cultivated flowers.
  • Flight Season: Late March to late October.
  • Eastern Tiger Swallowtail butterflies are “edge habitat specialists”. Look for them in the areas between meadows and forests.
    • More individuals are likely to be along the edges of flowery meadows and forests at any given time of day (Siu et al. 2016) than deep in either area.
  • These yellow butterflies are strong fliers and fly higher than many other butterflies.
    • When spooked, Eastern Tiger Swallowtail butterflies fly towards the woods and up into the trees to hide amongst the canopy.
  • Adult Eastern Tiger Swallowtail butterflies eat nectar from flowers with long petals and seem to prefer red, pink, and purple flowers (Daniels 2003).
    • North Carolina wildflowers that serve as nectar sources for this species include:
      • Butter Milkweed (Asclepias tuberosa)
      • Common Milkweed (Asclepias syriaca)
      • Wild Lupine (Lupinus perennis)
  • Other flowers from which they feed include:
    • Wild Bergamot (Monarda stulosa)
    • Hairy Beardtongue (Penstemone hirutus)
    • Dwarf Blazing Star (Liatris cylandracea)
    • Winter Vetch (Vicia villosa)
    • Clovers (Trifolium spp.)
    • Bouncing Bet (Saponaria oficianalis)

How to Identify Eastern Tiger Swallowtail Eggs, Caterpillars, And Chrysalises

Eggs

  • Female Eastern Tiger Swallowtail butterflies lay eggs one at a time on top of host plant leaves (Daniels 2003). The eggs are green, round, and very large for butterflies—about 0.03 by 0.05 inches (0.08 x 0.12 cm) (Pyle 1981).

Caterpillars

  • Grow to about 2 inches (5.5 cm) (Wagner 2005).
  • Eastern Tiger Swallowtail caterpillars are smooth and green.
    • Have a pair of yellow, blue, and black eye spots on third thoracic segment.
      • Each eye spot has a characteristic black “eyebrow” on the inner edge.
    • Have a yellow stripe between the third and fourth segments, but the stripe is not visible at rest (Wagner 2005).
  • Eastern Tiger Swallowtail caterpillars are “counter-shaded” (Wagner 2005).
    • Their backs are dark green but the color lightens gradually down their sides.
    • This coloration helps them blend into the leaves upon which they feed and avoid notice by predators.
  • Look for caterpillars on:
    • Trees in the Magnolia family (Magnoliaceae), including:
      • Sweetbay (Magnolia virginiana)
      • Southern Magnolia (Magnolia grandifolia)
      • Cucumber Tree (Magnolia acuminata)
      • Tulip Tree (Liriodendron tulipifera)
    • Ash trees (Fraxinus spp.)
    • Cherry trees (Prunus spp.)

Chrysalises

  • Eastern Tiger Swallowtail chrysalises are mottled green or brown, about 1.25 inches (3.2 cm) long (Pyle 1981), and belted with a single strand of silk.
  • Caterpillars overwinter in chrysalises until temperatures warm. In the spring, they metamorphose and emerge as the first generation of adults.