Rhagoletis pomonellaApple maggot

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Geographic Range

Rhagoletis pomonella are found in the eastern United States and southeastern Canada. More specifically, apple maggots range from Florida to Nova Scotia on the extreme east portion of its range, and from Texas to Alberta on the extreme west. (Arnett, 1985; Milne and Milne, 1980)

Habitat

Rhagoletis pomonella live primarily in apple orchards (hence the name) and at the edge of deciduous forests. (Milne and Milne, 1980)

Physical Description

Apple maggots have a yellow or orange head, and legs that range in color from bright yellow to gray. The thorax may range from shiny black to tan depending on enviroment, and is crossed by three white lines (in males) or four white lines (in females). These lines blur together at the sides of the thorax. Eyes are red, and the antennae's third segment is larger and more rounded than the other segments. Four dark bars, sometimes "F" shaped, are present on the wings, which lack an apical spot. (Arnett, 1985; Milne and Milne, 1980)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range length
    5 to 7 mm
    0.20 to 0.28 in

Development

Fertilized eggs are individually oviposited inside of host fruit. The majority of this fruit is consumed by larvae after hatching. Once the fruit is consumed, larvae drop to the ground and pupate through the winter. In July of the following year adult flies emerge and feed upon leaves and fruit until mating in late August to early September. (Arnett, 1985; Milne and Milne, 1980)

Reproduction

Males perform a courtship dance while the female watches, after which she may choose whether or not to copulate with him. She is attracted by a non-volatile aromatic hydrocarbon pheromone that is yet to be fully identified and classified. (Arnett, 1985; Garman, 1937; Milne and Milne, 1980)

Males perform a courtship dance while the female watches, after which she may choose whether or not to copulate with him. She is attracted by a non-volatile aromatic hydrocarbon pheromone that is yet to be fully identified and classified. Fertilized eggs are deposited singly into unripened apples (if available) or other fruit plants. (Arnett, 1985; Garman, 1937; Milne and Milne, 1980)

  • Breeding season
    August to September, adults emerge in July
  • Range gestation period
    21 to 32 days
  • Range
    63 to 170 days
  • Average
    107 days
  • Range age at sexual or reproductive maturity (female)
    20 from emergence to 103 days
  • Range age at sexual or reproductive maturity (male)
    20 from emergence to 103 days
  • Average age at sexual or reproductive maturity (male)
    41 days

Fertilized eggs are oviposited in unripe apples or other unripe fruit, which provides food for larvae after hatching. There is no further parental care after oviposition. (Garman, 1937; Milne and Milne, 1980)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

  • Range lifespan
    Status: captivity
    103 (high) days
  • Average lifespan
    Status: captivity
    41 days

Behavior

Communication and Perception

These flies communicate with each other primarily through contact pheromones. Most of these pheromones are either alkanes or alkenes, and they are highly volatile for maximum dispersion. The exception to this is the mating pheromone which has not been classified but is thought to be an aromatic. The flies commonly produce about twenty separate pheromones, although upwards of thirty have been identified. (Chapman, 1998; Milne and Milne, 1980; Chapman, 1998; Milne and Milne, 1980)

Food Habits

Apple maggots infest wild hawthorns, blueberries, and western snowberries. They are well known for their affinity for domesticated apples and are capable of ruining an entire crop.

Adults of this species subsist on scraping particles from the outer surface of leaves and fruit. In non-agricultural areas where apples are unavailable, they prefer blueberry bushes and western snowberries. (Arnett, 1985; Garman, 1937; Milne and Milne, 1980)

  • Plant Foods
  • leaves
  • fruit

Predation

Flies of the family Tephritae have a well studied ability to mimic primary predator's territorial behavior. Zonosemata vittigera, a member of the same family as R. pomonella, will wave its wings at an attacking spider in a display that closely matches this spiders intraspecific territorial display. In the majority of cases, this display will cause the attacking spider to back off, not wishing to fight what it sees as another spider over its terrritory. (Greene, et al., 17 April 1987; Milne and Milne, 1980)

Ecosystem Roles

Species Used as Host
  • apples

Economic Importance for Humans: Positive

There are no known positive economic benefits derived from this species. (Arnett, 1985)

Economic Importance for Humans: Negative

The apple maggot is an agricultural pest capable of decimating entire crops when in sufficient numbers. Even when using aggressive pest control methods are implemented, which may wipe out adult apple maggot populations one year, some pupae do not emerge until the following year making Rhagoletis pomonella very difficult to completely eradicate. (Arnett, 1985; Milne and Milne, 1980)

  • Negative Impacts
  • crop pest

Conservation Status

This species is at no risk of extinction and requires no special protective status.

Contributors

Sara Diamond (editor), Animal Diversity Web.

Stuart Nelson (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.

chemical

uses smells or other chemicals to communicate

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.

frugivore

an animal that mainly eats fruit

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.

oviparous

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

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

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.

visual

uses sight to communicate

References

Arnett, R. 1985. American Insects: A Handbook of the Insects of America North of Mexico. New York: Van Nostrand Reinhold Company.

Chapman, R. 1998. The Insects. New York: Cambridge University Press.

Garman, P. 1937. Notes on Breeding the Apple Maggot, Rhagoletis pomonella. Pp. 436-437 in P Galstoff, F Lutz, J Needham, P Welch, eds. Culture Methods for Invertebrate Animals. New York: Dover Pulications, Inc..

Greene, E., L. Orsak, D. Whitman. 17 April 1987. A Tephritid Fly Mimics the Territorial Displays of Its Jumping Spider Predators. Science, 236: 310-312.

Milne, L., M. Milne. 1980. Apple Maggot Fly (Rhagoletis pomonella). Pp. 675 in L Milne, M Milne, eds. The Audubon Society Field Guide to North American Insects. New York: Alfred A. Knopf.