Wikijunior:Bugs/Fruit Fly

What does it look like?

An adult Fruit Fly

Fruit Flies have distinctive markings on their wings, such as bands, patches, or zigzags. Scientists use these patterns to identify individual species.

Mediterranean Fruit Flies are also known as Medflies. They are about the size of a common house fly. Their wings have orange and brown markings. There are dark and light patterns on the head. The abdomen is orange with light stripes. The legs are orange.

Caribbean Fruit Flies are orange with black markings. They have long wings with yellow-brown to brown bands. They are also known as Greater Antilles Fruit Flies and Guava Fruit Flies. They can be 2 times larger than a common house fly.

Papaya Fruit Flies have a long, thin body. The head and mid-section (thorax) have orange patterns. The abdomen has brown stripes. The wings are long and thin. They lay straight back over the body.

Asian Papaya Fruit Flies are black. They have yellow patterns on the thorax. The wings are transparent.

Olive Fruit Flies are black with transparent wings. They have a reddish pattern on the head and abdomen.

European Fruit Flies are also known as “picture wing” flies. They are brown with tan stripes and have light spots on their wings.

Where does it live?

Fruit Flies occur worldwide and live in a wide variety of habitats.

Medflies are thought to have originated in Africa. They are now found in many other parts of the world.

Caribbean Fruit Flies are native to the West Indies. They are found in Cuba, Jamaica, Hispaniola, Puerto Rico, and South Florida.

Papaya Fruit Flies are found throughout tropical and subtropical areas of the western hemisphere. They are found in Central and South America. In the United States, they are found in southern Texas and southern Florida.

Asian Papaya Fruit Flies are found in Thailand, Malaysia, Borneo, Indonesia and Singapore, Papua New Guinea, and in Australian island territories.

Olive Fruit Flies probably came to the Middle East and southern Europe from Africa. Scientists believe they were recently introduced to California olive groves from the Mediterranean region.

What does it eat?

Caribbean Fruit Flies infest only mature to overripe fruits. They feed on peaches, plums, oranges, grapefruit, guavas, rose-apples, and cherries.

Papaya Fruit Flies eat papaya, mango, and milkweed.

Adult Olive Fruit Flies feed on various substances including honeydew from insects, pollen, and bird droppings.

European Fruit Flies feed on the flowerheads of ragwort.

How does it defend itself?

Scientists have found that some fruit fly species change colors and patterns within a few generations. To blend in with different surroundings, a new generation may become darker or lighter than previous generations. Scientists believe this adaptation makes the new generation of fruit flies less visible and protects them from predators.

What stages of metamorphosis does it go through?

Fruit Flies undergo complete metamorphosis, changing to adulthood in several stages: egg, early larva, full-sized larva, pupa, and adult. In the pupa stage, they “rest” before the final molt when they emerge as full grown adults. Eggs are laid on plants. The larval stage is the first stage after leaving the egg. Larvae vary in shape and are smooth or slightly spiny. Some larvae feed and grow inside soft fruits or flowers. Other larvae are leaf-miners. They bore their way through the leaf and make yellow squiggly lines. Leaf-miner damage can also appear as spots or blotches. Sometimes, when larva, hatch they cause galls (swellings) on the leaf. The galls provide protection and food for the growing larvae.

Medfly females deposit their eggs in fruit skin that has been softened by damage. The eggs hatch within 3 days. Larvae grow inside the fruit. The flesh of the fruit decomposes as larvae feed. When fully grown, larvae stop feeding and leave the fruit. They burrow into the soil, remain inactive (pupate), and slowly develop into adults. Adults escape from the pupal case and burrow up through the soil. The amount of time from egg to adult varies from 5 weeks to 5 months, depending on temperature. Adults may live 2 to 3 months.

Caribbean Fruit Fly eggs are laid one at a time and hatch in 2 to 3 days. The larvae feed and grow for about 2 weeks. The pupal, non-feeding period is about the same. Development from egg to adult takes longer in cooler weather.

Female Papaya Fruit Flies produce hundreds of long, slender eggs. The eggs are deposited in immature papaya fruit. Young larvae feed on developing seeds in the center of the fruit until it is ripe. Then they eat their way out and drop to the ground. They mature in the soil beneath the plant. Adults emerge in 2 to 6 weeks.

Asian Papaya Fruit Flies lay their eggs just under the skin of the fruit. Small discolored patches appear where the female punctures the fruit to lay eggs. Within 1 to 2 days, eggs hatch into larvae which feed on the decaying fruit. After the decayed fruit drops to the ground, it takes 7 to 12 days for the larvae to leave the fruit and burrow into the soil to pupate. Mature adults emerge about 2 weeks later. In 1 to 2 more weeks mating begins. They live for several months and reproduce throughout their life span. They are able to multiply rapidly and disperse over great distances.

Olive Fruit Flies only reproduce on olive fruit. Females prefer large green olives for egg-laying. Eggs are laid under the skin of the fruit. In a few days the larvae appear. They feed on the pulp and pass through 3 larval stages. Pupae develop inside the fruit or on the ground.

What special behavior does it exhibit?

When courting females, male Medflies sing a unique “calling song.” A female will mate with a male whose sounds are most attractive to her.

How does this bug affect people?

Many Fruit Fly species cause extensive damage to crops and fruit trees. Countries and states make rules against importing fruit from areas where Fruit Fly infestation has occurred.

Medflies damage citrus and other soft fruits. They multiply rapidly. Traps are placed on trees. If just one is found in a trap, farmers quarantine (isolate) the area. Steps are taken to prevent Medflies from spreading to other areas. Pesticides, that are safe for people, are sprayed on plants or applied to soil to destroy adults and larvae.

Asian Papaya Fruit Flies are a serious pest worldwide. They infest virtually all fruit. They do not infest pineapples, legumes, sweet corn, macadamia nuts, or coconuts.

Olive Fruit Flies have been the major pest of olive crops worldwide since biblical times.