fruit sugar: see fructose.

fruit fly, common name for any of the flies of the families Tephritidae and Drosophilidae. All fruit flies are very small insects that lay their eggs in various plant tissues. The Tephritidae contains about 1,200 species characterized by wide heads, black or steely green or blue bodies, iridescent greenish eyes, and wings that are usually mottled brown or black. The eggs of most species are laid directly in the pulp of the fruit on which the larvae feed; in North America, blueberries, cherries, and apples are much damaged by these insects. In warm regions, the Mediterranean fruit fly, Ceratitis capitata, was a serious pest of citrus fruits; it has now been eradicated from the S United States. Some species, e.g., the goldenrod gall fly, Eurosta solidaginis, which deposits its eggs in species of goldenrod, lay their eggs in plants of no economic importance. The Drosophilidae, or pomace flies, are yellowish and in the wild are largely found around decaying vegetation. The larvae living in fruit actually feed on the yeasts growing in the fruit. Drosophila melanogaster, also called vinegar fly, is a much used laboratory insect; its 10-day life cycle and large chromosomes, particularly those of the salivary glands of the larva, have made it invaluable in the study of genetics. Fruit flies are classified in the phylum Arthropoda, class Insecta, order Diptera, families Tephritidae and Drosophilidae.

fruit bat, fruit-eating bat found in tropical regions of the Old World. It is relatively large and differs from other bats in the possession of an independent, clawed second digit; it also depends on sight rather than echo-location in maintaining orientation. The Pteropodidae, or flying foxes, are S Asian fruit bats whose short jaws and powerful teeth are specially adapted for piercing the rinds of tough fruit. They include the largest of all bats, the kalang (Pteropus vampyrus), which has a wingspan greater than 5 ft (1.5 m). The Macroglossidae, or long-tongued fruit bats, are widespread throughout S Asia, Africa, New Guinea, and Australia. Specialized for a diet of pollen and nectar, their snouts and tongues are greatly elongated. All fruit bats are highly mobile, traveling as much as 30 mi (48 km) in search of food. They nest in trees and all but a few species are completely nocturnal. Fruit bats are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Chiroptera.

fruit, matured ovary of the pistil of a flower, containing the seed. After the egg nucleus, or ovum, has been fertilized (see fertilization) and the embryo plantlet begins to form, the surrounding ovule (see pistil) develops into a seed and the ovary wall (pericarp) around the ovule becomes the fruit. The pericarp consists of three layers of tissue: the thin outer exocarp, which becomes the "skin"; the thicker mesocarp; and the inner endocarp, immediately surrounding the ovule. A flower may have one or more simple pistils or a compound pistil made up of two or more fused simple pistils (each called a carpel); different arrangements give rise to different types of fruit. A new variety of fruit is obtained as a hybrid in plant breeding or may develop spontaneously by mutation.

Types of Fruits

Fruits are classified according to the arrangement from which they derive. There are four types—simple, aggregate, multiple, and accessory fruits. Simple fruits develop from a single ovary of a single flower and may be fleshy or dry. Principal fleshy fruit types are the berry, in which the entire pericarp is soft and pulpy (e.g., the grape, tomato, banana, pepo, hesperidium, and blueberry) and the drupe, in which the outer layers may be pulpy, fibrous, or leathery and the endocarp hardens into a pit or stone enclosing one or more seeds (e.g., the peach, cherry, olive, coconut, and walnut). The name fruit is often applied loosely to all edible plant products and specifically to the fleshy fruits, some of which (e.g., eggplant, tomatoes, and squash) are commonly called vegetables. Dry fruits are divided into those whose hard or papery shells split open to release the mature seed (dehiscent fruits) and those that do not split (indehiscent fruits). Among the dehiscent fruits are the legume (e.g., the pod of the pea and bean), which splits at both edges, and the follicle, which splits on only one side (e.g., milkweed and larkspur); others include the dry fruits of the poppy, snapdragon, lily, and mustard. Indehiscent fruits include the single-seeded achene of the buttercup and the composite flowers; the caryopsis (grain); the nut (e.g., acorn and hazelnut); and the fruits of the carrot and parsnip (not to be confused with their edible fleshy roots).

An aggregate fruit (e.g., blackberry and raspberry) consists of a mass of small drupes (drupelets), each of which developed from a separate ovary of a single flower. A multiple fruit (e.g., pineapple and mulberry) develops from the ovaries of many flowers growing in a cluster. Accessory fruits contain tissue derived from plant parts other than the ovary; the strawberry is actually a number of tiny achenes (miscalled seeds) outside a central pulpy pith that is the enlarged receptacle or base of the flower. The core of the pineapple is also receptacle (stem) tissue. The best-known accessory fruit is the pome (e.g., apple and pear), in which the fleshy edible portion is swollen stem tissue and the true fruit is the central core. The skin of the banana is also stem tissue, as is the rind of the pepo (berrylike fruit) of the squash, cucumber, and melon.

The Role of Fruits in Seed Dispersal

The structure of a fruit often facilitates the dispersal of its seeds. The "wings" of the maple, elm, and ailanthus fruits and the "parachutes" of the dandelion and the thistle are blown by the wind; burdock, cocklebur, and carrot fruits have barbs or hooks that cling to fur and clothing; and the buoyant coconut may float thousands of miles from its parent tree. Some fruits (e.g., witch hazel and violet) explode at maturity, scattering their seeds. A common method of dispersion is through the feces of animals that eat fleshy fruits containing seeds covered by indigestible coats.

Mediterranean fruit fly: see fruit fly.

Fruit in which the outer layer is a thin skin, the middle layer is thick and usually fleshy (though sometimes tough, as in the almond, or fibrous, as in the coconut), and the inner layer (the pit) is hard and stony. Within the pit is usually one seed. In aggregate fruits such as the raspberry and blackberry (which are not true berries), many small drupes are clumped together. Other representative drupes are the cherry, peach, mango, olive, and walnut.

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Edible fruit of the vine Actinidia chinensis (family Actinidiaceae), native to mainland China and the island of Taiwan and grown commercially in New Zealand and California. It became popular in the nouvelle cuisine of the 1970s. It has a slightly acid taste and is high in vitamin C. Kiwi can be eaten raw or cooked, and the juice is sometimes used as a meat tenderizer.

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or levulose or fruit sugar

Organic compound, one of the simple sugars (monosaccharides), chemical formula C₆H₁₂O₆. It occurs in fruits, honey, syrups (especially corn syrup), and certain vegetables, usually along with its isomer glucose. Fructose and glucose are the components of the disaccharide sucrose (table sugar); hydrolysis of sucrose yields invert sugar, a 50:50 mixture of fructose and glucose. The sweetest of the common sugars, fructose is used in foods and medicines.

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Any dipteran species of two families: large fruit flies (Trypetidae) and small fruit flies, or vinegar flies (family Drosophilidae; see drosophila). The larvae feed on fruit or other vegetation. The adults' wings are banded or spotted with brown. Many species attack cultivated fruits, sometimes causing enough damage to create significant economic loss. Some species are leaf miners; others burrow in plant stems. Well-known fruit-fly pests include the Mediterranean fruit fly and the apple maggot of the U.S., the Mexican and Oriental fruit flies, and the olive fruit fly of the Mediterranean region.

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Any of numerous tropical Old World bats in the family Pteropodidae as well as several species of herbivorous New World bats. Old World fruit bats are widely distributed from Africa to South Asia and Australasia. Most species rely on vision rather than on echolocation to avoid obstacles. Some species are solitary, some gregarious; most roost in the open in trees, though some inhabit caves, rocks, or buildings. Some are red or yellow, and some are striped or spotted. They eat fruit or flowers (including pollen and nectar). The smallest species in the family, the long-tongued fruit bats, reach a head and body length of about 2.5 in. (6–7 cm) and a wingspan of about 10 in. (25 cm). The same family contains the largest of all bats, the flying foxes, which attain lengths up to 16 in. (40 cm) and a wingspan of 5 ft (1.5 m). New World fruit bats are generally smaller and make use of echolocation. They are found in the tropics, with many species belonging to the genera Artibeus and Sturnira.

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In its strict botanical sense, the fleshy or dry ripened ovary (enlarged portion of the pistil) of a flowering plant, enclosing the seed or seeds. Apricots, bananas, and grapes, as well as bean pods, corn grains, tomatoes, cucumbers, and (in their shells) acorns and almonds, are all technically fruits. Popularly, the term is restricted to the ripened ovaries that are sweet and either succulent or pulpy. The principal botanical purpose of the fruit is to protect and spread the seed. There are two broad categories of fruit: fleshy and dry. Fleshy fruits include berries, such as tomatoes, oranges, and cherries, which consist entirely of succulent tissue; aggregate fruits, including blackberries and strawberries, which form from a single flower with many pistils, each of which develops into fruitlets; and multiple fruits, such as pineapples and mulberries, which develop from the mature ovaries of an entire inflorescence. Dry fruits include the legumes, cereal grains, capsules, and nuts. Fruits are important sources of dietary fiber and vitamins (especially vitamin C). They can be eaten fresh; processed into juices, jams, and jellies; or preserved by dehydration, canning, fermentation, and pickling.

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or Med fly

Fruit fly (Ceratitis capitata) proven to be particularly destructive to citrus crops, at great economic cost. The Med fly lays up to 500 eggs in citrus fruits (except lemons and sour limes), and the larvae tunnel into the fruit, making it unfit for human consumption. Because of this pest, quarantine laws regulating fruit importation have been enacted worldwide.

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