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Biological pest control waspsExtant Early Cretaceous first appearancesMymaridaeTaxa named by Alexander Henry Haliday

Fairyfly

Adapted from Wikipedia · Discoverer experience

A tiny fairyfly wasp from Thailand, showcasing nature's delicate insects.

The Mymaridae, commonly known as fairyflies or fairy wasps, are a family of very tiny insects called chalcidoid wasps. You can find them all around the world, in temperate, subtropical, and tropical places. There are about 100 different groups, or genera, of fairyflies, with around 1,400 known species.

Fairyflies are some of the smallest insects on Earth. Most of them are only about half a millimeter to one millimeter long—that’s smaller than a grain of sand! They come in colors like black, brown, or yellow, and their wings look feathery because of tiny bristles. These wings help them move through the air, which feels like thick honey to such tiny creatures. One type of fairyfly holds the record for being the world's smallest known insect, measuring just 0.139 millimeters long, and another is the smallest known flying insect, only 0.15 millimeters.

Even though they are tiny, fairyflies play an important role in nature. They are parasitoids, which means they lay their eggs inside the eggs of other insects. When the fairyfly larvae hatch, they eat the host egg from the inside, eventually killing the host. Because of this ability, some fairyfly species are used by scientists as biological pest control to help manage harmful insect populations without using chemicals. Their lives as adults are very short, often lasting just a few days.

Taxonomy

An illustration of the 'feather-winged' Mymar pulchellum by John Curtis, c. 1840

The family Mymaridae, known as fairyflies or fairy wasps, was first described in 1833 by Irish entomologist Alexander Henry Haliday. Haliday and his friends, John Curtis and Francis Walker, were important in studying Hymenoptera in the 1800s.

Fairyflies are very tiny insects, and they are popular among scientists who study very small things under microscopes. There are about 1,424 species of fairyflies grouped into around 100 different groups called genera. Some of the most common fairyflies belong to groups like Anagrus, Anaphes, Gonatocerus, and Polynema.

Description

Mymarilla wollastoni: (1) Female exhibiting the extraordinarily densely hairy (setose) and domed forewings peculiar to the species. (2) Close-up of the thread-like antennae of a male. Mymarilla wollastoni is endemic to the island of Saint Helena in the southern Atlantic. Scale bar = 1 mm

Fairyflies are very tiny insects, usually only about as long as a grain of sand, ranging from 0.5 to 1.0 mm. They are often colored black, brown, or yellow and have long antennae. These little insects have special patterns on their bodies that help them stand out from other similar wasps.

Most fairyflies have wings with tiny hairs along the edges. Their wings can look quite different from each other—some are wide and flat, while others are very narrow and long. In some places, fairyflies might have smaller wings or no wings at all, especially if they live in windy areas or tight spaces where wings would not be helpful. Despite their tiny size, fairyflies are fascinating little creatures!

Distribution and habitat

Fairyflies are very tiny wasps that are found all over the world, especially in temperate and tropical areas. They live in many different places, from deserts to rainforests, and some can even live in water, like in freshwater ponds and streams. One special type, called Caraphractus cinctus, can swim using its wings and stay underwater for up to 15 days. Because they are so small, fairyflies often go unnoticed by humans.

Ecology

Arescon sp. (female) from Thailand

All known fairyflies are parasitoids of eggs of other insects. They lay their eggs in hidden places, like inside plant tissues or underground. Fairyflies do not choose specific host species; some can parasitize many different insects. Their most common hosts are true bugs, such as leafhoppers, cicadas, and scale insects, but they can also target beetles, flies, dragonflies, booklice, and thrips.

Fairyflies include the smallest known insect, Dicopomorpha echmepterygis from Illinois, whose males are only 0.139 mm long. These tiny males do not have wings or eyes, and their bodies are smaller than a single-celled Paramecium. The smallest flying insect is another fairyfly, Kikiki huna from Hawaii, measuring 0.15 mm in length.

Economic importance

Gonatocerus triguttatus laying its eggs in glassy-winged sharpshooter eggs embedded in a leaf

Fairyflies are important because they help control pests that damage crops. They lay their eggs inside the eggs of pests, stopping the pests from growing. One type of fairyfly, called Anagrus, has been used in many places to control pests.

In Hawaii, a fairyfly helped control a pest that harms sugarcane. In California, fairyflies were used to control pests on grapes. They survived by finding other insects to use as hosts during winter. Fairyflies have also been used in Tahiti, Moorea, and other islands to reduce pests that damage crops. They have been very successful in lowering pest numbers.

Fossil record

Compression fossil of Gonatocerus greenwalti from Montana

Fairyflies have been found preserved in fossil amber inclusions, copal, and compression fossils dating from the Early Cretaceous to the Miocene epoch. They are the only family of chalcidoid wasps known to have existed in the Cretaceous period.

Scientists have described fairyfly fossils from different time periods. In 1901, Fernand Anatole Meunier described fossils from Baltic amber dating to the Eocene. Later discoveries include fossils from the Burdigalian amber of Mexico, the Oligocene Baltic amber, and the oil shales of the Kishenehn Formation in Montana. The oldest known fairyfly, from the Lower Cenomanian age of the Late Cretaceous, was described in 2011 from Burmese amber. This ancient fairyfly looks much like modern ones but has some slightly different features.

Genera

The Mymaridae family includes many tiny insects called fairyflies. Some of these insects have been moved to different families or are considered the same as other species. There are both living and ancient fairyfly species discovered in fossils.

Extant genera

The following are the currently recognized living genera of fairyflies:

Fossil genera

These fossil genera are classified under Mymaridae:

Collection and preservation

See also: Insect collecting

A Malaise trap

Fairyflies are tiny insects that are hard to collect, even though they are common. In the past, people used special nets to catch them, but today, scientists often use Malaise traps, yellow pan traps, sweep nets, and suction traps to gather them. Another way to study fairyflies is by watching their growth from eggs found in nature or in labs.

Keeping fairyflies as specimens can be tricky because they are so small. Special care is needed to dry and mount them without breaking their delicate bodies.

Images

A detailed close-up of a tiny parasitic wasp species, Cremnomymar sp., showing its wing structure under scientific magnification.
A close-up photograph of a small parasitic wasp specimen, Paracmotemnus sp., showcasing its delicate wings and body structure for educational study.
A close-up photograph of an Acmotemnus luteiclava, a tiny parasitic wasp, showcasing its delicate features for educational purposes.
A fossil of Myanmymar aresconoides preserved in amber, showcasing ancient insect life.
A scientific photograph of a female Allanagrus magniclava, a type of parasitic wasp, for educational use.
A detailed close-up photograph of a tiny parasitic wasp specimen used for scientific study.
A tiny parasitic wasp (Camptopteroides verrucosa) – a fascinating insect from the Mymaridae family.
A fossilized insect preserved in amber, showing detailed scientific characteristics of the species Enneagmus pristinus.

This article is a child-friendly adaptation of the Wikipedia article on Fairyfly, available under CC BY-SA 4.0.

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