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Phyciodes tharos

By Sara Diamond and Jamie King

Geographic Range

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)

Habitat

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)

Physical Description

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

Development

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

Reproduction

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
    36

After oviposition, there is no further parental involvement.

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

Behavior

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)

Food Habits

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

Economic Importance for Humans: Positive

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

Economic Importance for Humans: Negative

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

Conservation Status

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

Other Comments

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)

Contributors

Sara Diamond (author), Animal Diversity Web.

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

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nectarivore

an animal that mainly eats nectar from flowers

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

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.

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