Apple maggot
Encyclopedia
The apple maggot also known as railroad worm, is a pest of several fruit
s, mainly apple
s. The adult form of this insect is about 5 mm (0.2 inch) long, slightly smaller than a house fly, with a white dot on its thorax and a characteristic black banding shaped like an "F" on its wings. The larva, which is the stage of this insect's life cycle
that causes the actual damage to the fruit, is similar to a typical fly larva or maggot. Other "worms," especially the larvae of the codling moth
, that infest the insides of apples are often confused with the apple maggot. Generally speaking, however caterpillars often feed in the apple’s core while apple maggots feed on the fruit flesh. In infested fruit, the larvae are often difficult to detect due to their pale, cream colour and small body size. The maggot stage has many enemies, including several braconid wasps: Utetes canaliculatus, Diachasmimorpha mellea
, and Diachasma alloeum
.
The adult stage lays its egg
s inside the fruit; before the arrival of apples from Europe
, it was found mainly in hawthorn
s. The young "worm" that hatches consumes the fruit (rarely will the larva leave the fruit while it is still hanging on the tree), and causes it to bruise and decay and finally drop before ripening. The insect overwinters as a pupa in the soil. It only emerges after metamorphosis into a relatively defenseless fly. It uses batesian mimicry
as a method of defense - its coloration resembles that of the forelegs and pedipalps of a jumping spider
(family Salticidae). Adults emerge from late June through September, with their peak flight occurring in August.
feeding race in the 1800 - 1850 CE time frame after apples were introduced into North America. The apple feeding race does not now normally feed on hawthorns and the hawthorn feeding race does not now normally feed on apples. This constitutes a possible example of an early step towards the emergence of a new species, a case of sympatric speciation
.
The emergence of the apple race of Rhagoletis pomonella also appears to have driven formation of new races among its parasites.
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s, mainly apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
s. The adult form of this insect is about 5 mm (0.2 inch) long, slightly smaller than a house fly, with a white dot on its thorax and a characteristic black banding shaped like an "F" on its wings. The larva, which is the stage of this insect's life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
that causes the actual damage to the fruit, is similar to a typical fly larva or maggot. Other "worms," especially the larvae of the codling moth
Codling moth
The codling moth is a member of the Lepidopteran family Tortricidae. They are known as an agricultural pest, their larva being the common apple worm or maggot. It is native to Europe and was introduced to North America, where it has become one of the regular pests of apple orchards. It is found...
, that infest the insides of apples are often confused with the apple maggot. Generally speaking, however caterpillars often feed in the apple’s core while apple maggots feed on the fruit flesh. In infested fruit, the larvae are often difficult to detect due to their pale, cream colour and small body size. The maggot stage has many enemies, including several braconid wasps: Utetes canaliculatus, Diachasmimorpha mellea
Diachasmimorpha mellea
Diachasmimorpha mellea is a parasitoid of Rhagoletis pomonella, the apple maggot fly. It is morphologically very similar to another apple maggot parasitoid, Diachasma alloeum....
, and Diachasma alloeum
Diachasma alloeum
Diachasma alloeum is a small wasp in the family Braconidae. It is a parasitoid of Rhagoletis pomonella, the apple maggot. The wasp lays its eggs into third instar larvae of the fly, which then develop after the larvae have pupated...
.
The adult stage lays its egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s inside the fruit; before the arrival of apples from Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, it was found mainly in hawthorn
Crataegus
Crataegus , commonly called hawthorn or thornapple, is a large genus of shrubs and trees in the rose family, Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe,...
s. The young "worm" that hatches consumes the fruit (rarely will the larva leave the fruit while it is still hanging on the tree), and causes it to bruise and decay and finally drop before ripening. The insect overwinters as a pupa in the soil. It only emerges after metamorphosis into a relatively defenseless fly. It uses batesian mimicry
Batesian mimicry
Batesian mimicry is a form of mimicry typified by a situation where a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator...
as a method of defense - its coloration resembles that of the forelegs and pedipalps of a jumping spider
Jumping spider
The jumping spider family contains more than 500 described genera and about 5,000 described species, making it the largest family of spiders with about 13% of all species. Jumping spiders have some of the best vision among invertebrates and use it in courtship, hunting and navigation...
(family Salticidae). Adults emerge from late June through September, with their peak flight occurring in August.
Evolution
Rhagoletis pomonella is significant evolutionarily in that the race of this species that feeds on apples spontaneously emerged from the hawthornCrataegus
Crataegus , commonly called hawthorn or thornapple, is a large genus of shrubs and trees in the rose family, Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe,...
feeding race in the 1800 - 1850 CE time frame after apples were introduced into North America. The apple feeding race does not now normally feed on hawthorns and the hawthorn feeding race does not now normally feed on apples. This constitutes a possible example of an early step towards the emergence of a new species, a case of sympatric speciation
Sympatric speciation
Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap or are even identical, so that...
.
The emergence of the apple race of Rhagoletis pomonella also appears to have driven formation of new races among its parasites.
External links
- Popular Account Bugs of Wormy Apples, Part 2 Copyright © 1999 by Louise Kulzer
- Ohio State University Fact Sheet
- Apple Maggot Fly Traps - Ladd Research
- apply maggot fly on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
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