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Chrysops vittatus

By Ginger Hartwell

Geographic Range

Chrysops vittatus can be found in the eastern half of the United States and the southeastern part of Canada. (Bland, 1978)

Habitat

Species in the genus Chrysops are found in open woodlands and wetland areas, especially near the margins of streams and ponds. (Robinson, 1996)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Deer flies (Chrysops spp.) are generally smaller in size (10-12mm) than their cousins the horse flies (Tabanus spp.). Chrysop vittatus is known as the striped deer fly due to the three longitudinal stripes on its thorax, and four stripes on its broad, blunt abdomen. The entire insect is yellowish in color, and the antennae have three functional segments with the distal segments being fused. Large, laterally extended, iridescent eyes are characteristic of the entire Tabanidae family. Female C. vittatus have a space between the compound eyes while males do not. Females have mouthparts modified for piercing flesh. There are two flattened mandibles with serrations, two narrow, serrated maxillae, a hypopharynx, and a median labrum-epipharynx. The mandibles cut the integument and the maxillae pierce the tissue, rupturing the blood vessels. The food canal is formed by the hypopharynx and labrum-epipharynx. (Bland, 1978; Dunn, 1996; Imms, 1948; Roberts and Janvoy, 1996)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    10 to 12 mm
    0.39 to 0.47 in

Development

Complete larval development in the family Tabanidae generally takes about a year, although some species require two or more years. Eggs are laid in large batches in or near water, and the larvae of this species can be found at the margins of streams and ponds, or in wetland soil. Although the larvae live in water, they do not have gill-like structures for breathing oxygen, so they must come to the surface to breathe. When the pupae are formed they can be found in dead vegetation above the free-water level. After adults emerge the mating cycle begins again. (Hostetter, 1997; Robinson, 1996; Ross, 1948)

Reproduction

Little information is available on the exact mating behaviors of Chrysops vittatus.

Adult flies mate relatively quickly after emerging, and oviposition depends on the female having a blood meal. The blood meal serves as nourishment for the eggs' maturation. Eggs are laid in large batches in or near water and the larvae of this species can be found at the margins of streams and ponds or in wetland soil. (Hostetter, 1997; Robinson, 1996; Ross, 1948)

Once eggs are laid in a suitable location for larval development, there is no further parental investment.

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

Food Habits

Chrysops is a genus of parasitic flies that feed on the blood of mammals. Female adults gorge on blood by cutting the skin with their modified mouthparts and sucking the blood from the wound. Males lack these piercing mouthparts, and generally feed on the nectar of plants. Larvae of this species feed on organic debris found in their surrounding environment. Larvae can also be predaceous, feeding on other insect larvae or worms. In rural areas of the eastern United States, there is a large population of deer (Odocoileus), which are an excellent source of food for C. vittatus. (Hostetter, 1997; Roberts and Janvoy, 1996; Robinson, 1996; Ross, 1948)

  • Animal Foods
  • blood
  • insects
  • terrestrial worms
  • Plant Foods
  • nectar
  • pollen

Ecosystem Roles

Species Used as Host

Economic Importance for Humans: Negative

This species can be quite an annoying pest during the summer months. Although a painful bite and a small welt is the extent of harm done to the body, these flies can discourage tourists from visiting the recreational areas that the species inhabits. (Robinson, 1996)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

This species is in no danger of extinction.

Contributors

Sara Diamond (editor), Animal Diversity Web.

Ginger Hartwell (author), University of Michigan-Ann Arbor, Teresa Friedrich (editor), University of Michigan-Ann Arbor.

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

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.

carnivore

an animal that mainly eats meat

ectothermic

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

fertilization

union of egg and spermatozoan

forest

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

freshwater

mainly lives in water that is not salty.

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.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

sanguivore

an animal that mainly eats blood

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).

terrestrial

Living on the ground.

References

Bland, R. 1978. How To Know the Insects. Dubuque, Iowa: W.M.C. Brown Company Publishers.

Dunn, A. 1996. Insects of the Great Lakes Region. University of Michigan.

Hostetter, M. 1997. That Gunk on Your Car, A Unique Guide to Insects of North America. Berkeley, California: Ten Speed Press.

Imms, A. 1948. A General Textbook of Entomology. New York: E.P. Dutton & Co., Inc..

Roberts, L., J. Janvoy. 1996. Foundations of Parasitology, 6th edition.. The McGraw-Hill Companies, Inc..

Robinson, W. 1996. Urban Entomology. London: Chapman and Hall, 2-6 Boundary Row.

Ross, H. 1948. A Textbook of Entomology. New York: John Wiley and Sons Inc..

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