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Phyciodes tharos

What do they look like?

Phyciodes tharos is a small to medium sized butterfly that is 16-18 mm in length, with a wingspan of 3-4 cm. There are characteristic traits that differentiate males from females. Female wing coloration is generally darker than in males, with paler median spots. Males have black antennal knobs, which females lack altogether. The butterfly's coloration is black and vibrant orange, but the markings can vary geographically and can change from season to season. Spring butterflies tend to be darker than summer generations and have grey mottled hindwings. Typically, the upperside of the wings are brighter orange with marks on the forewings. The underside of the hindwings are an unmarked orange-brown to gray-brown, with a white cresent along the outer margin. Eggs are green. Larvae are chocolate brown, have a white mid-dorsal line, and are covered with tiny white dots. As larvae develop, caterpillars turn black and gain yellow bands on thier sides and spots along their back. The caterpillar also has eight rows of brown-yellow spines. (Carter, 1992; Scott, 1986)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • sexes shaped differently
  • Range length
    16 to 18 mm
    0.63 to 0.71 in
  • Range wingspan
    3 to 4 cm
    1.18 to 1.57 in

Where do they live?

The pearl crescent butterfly ranges from Alberta, Canada down south along the east coast of the United States into Mexico. It has also been seen in Montana, Wyoming, Colorado, New Mexico, Arizona, southeastern California, and Mexico. This species is not found in the Pacific Northwest. (Klots, 1951; Scott, 1986)

What kind of habitat do they need?

The pearl crescent prefers open, moist, and sunny places. It is commonly found along roadsides, fields and meadows, open pine forests, and vacant lots. (Klots, 1951; Scott, 1986; Taylor, 1994)

  • These animals are found in the following types of habitat
  • temperate

How do they grow?

As larvae develop, caterpillars turn black and gain yellow bands on thier sides and spots along their back. (Carter, 1992; Scott, 1986)

How do they reproduce?

During courtship, the male pursues the female butterfly while he is patroling the host plant. If the female is flying, she lands, keeping her wings spread. Next, the male lands behind her, possibly displaying his wings and on occasion fluttering them. With his wings partially opened he crawls under her hindwings to mate. For highly receptive females, which are usually motionless, the male rarely displays or flutters before mating. On the other hand, an unreceptive female will close her wings, possibly causing the male to leave. If the male doesn't fly away, the female may raise her abdomen (so he cannot join), turn and crawl away, drop down into vegetation, or fly away to escape. (Carter, 1992; Klots, 1951; Scott, 1986)

Females lay eggs in masses of 20-200 (average 36), sometimes two or three layers deep on the underside leaves of a host plant (usually aster leaves).

  • Range eggs per season
    20 to 200
  • Average eggs per season

After oviposition, there is no further parental involvement.

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

How do they behave?

The pearl crescent will descend onto leaves, stones, flowers,or bare ground. In the field, Phyciodes tharos can be identified by the way it holds it wings out to the side and "saws them up and down" during its descent (Klots and Klots 1951). This species also keeps its wings spread at rest, basking in the sun, or feeding. Like most brushfooted butterflies, the pearl cresent is a puddle visitor, and males will behave territorially toward other males approaching the same puddle -especially around the puddles where females tend to group. They have been recorded darting after other butterflies that come near its perch or puddle and driving them out of the area. Various theories speculate the cause of activity is to drive out competing males from claiming territory or mating with females as they pass through quickly. This is studied as an evolutionary adaptation that offers increased chance of success in search for a partner and ensures that the offspring receive food and protection. The Pearl Crescent has been seen chasing more than just other males of their species. Due to their investigative and aggressive behavior, they have been observed flying out at passing objects, including butterflies of different species, insects, birds and frisbees. They will even leave their path of flight to observe human activities. Phyciodes tharos has different flight patterns depending on region. In warmer climates such as Texas and Florida there are several flights throughout the year, whereas in northern regions there are few flights, and only from May to September. From April to November there are several broods in the north. In the south (Florida, Texas, New Mexico, and Mexico) there are three to four broods throughout the year. (Klots, 1951; Schneck, 1990; Scott, 1986; Taylor, 1994)

What do they eat?

The adult uses a siphoning technique to feed on nectar from an array of flowers including dogbane, swamp milkweed, shepherd's needle, asters, black-eyed susans, thistle, gloriosa daisies, white clover, and winter cress. The butterfly siphons nectar out of the flower by using its coiled tongue (proboscis). Caterpillars have chewing mouthparts used to eat leaves and other materials off of plants. (Klots, 1951; Pyle, 1984)

  • Plant Foods
  • leaves
  • nectar
  • flowers

Do they cause problems?

This butterfly has little economic significance, although larvae can be a nuisance, eating the leaves off of their host plants. (Scott, 1986; Taylor, 1994)

How do they interact with us?

This species of butterfly has no known economic importance. (Pyle, 1984)

Are they endangered?

The pearl crescent butterfly is in no danger of extinction, although it may be rare in parts of its range, especially at the periphery.

Some more information...

The pearl crescent is one the most common of 700 species of butterflies in the United States and Canada. Many subspecies of Phyciodes tharos have been identified. Phyciodes tharos arctica, found in Newfoundland, has a deeper more orange and yellow underside. Phyciodes tharos tharos, a subspecies found in New York, is lighter than the subspecies found in Newfoundland. Other subspecies found in Colorado and Washington are Phyciodes tharos morpheus and << Phyciodes campestris>>. Similar species to P. tharos are the Silvery Checkerspot and Phaon Crescent. (Klots, 1951; Scott, 1986; Taylor, 1994)


Sara Diamond (author), Animal Diversity Web.

Jamie King (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.


Carter, D. 1992. Eyewitness Handbook of Butterflies and Moths. New York: Dorling Kindersley, Inc.

Klots, A. 1951. Field Guide to Butterflies of North America, East of the Great Plains. Boston: Houghton Mifflin Co..

Pyle, R. 1984. Audubon Society for Butterfly Watchers. New York: Charles Scribner's Sons.

Schneck, M. 1990. Butterflies. Pennsylvania: Rodale Press.

Scott, J. 1986. The Butterflies of North America. Standford, California: Stanford University Press.

Taylor, J. 1994. Some Common Butterflies. Conservationist, March-June, 1994: 48, 5-6, 10-13.

University of Michigan Museum of ZoologyNational Science Foundation

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King, J. 2001. "Phyciodes tharos" (On-line), Animal Diversity Web. Accessed March 01, 2024 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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