Hoverfly

Hoverflies, also called flower flies or syrphids, are interesting insects that belong to the family Syrphidae. They are often seen hovering or feeding at flowers. The adults of many species eat nectar and pollen, while the larvae, also known as maggots, eat many different foods. Some larvae eat decaying plant and animal matter, while others eat insects like aphids, thrips, and other pests that harm plants.

Because some hoverfly larvae eat aphids, which are pests for crops, these insects are very important for nature and farming. The larvae can help control pest populations naturally, and the adults help by pollinating flowers.

There are about 6,000 species of hoverflies found all around the world, on every continent except Antarctica. Even though they look like stinging wasps and bees to scare away predators, hoverflies are harmless to most mammals. Their ability to hover in one spot in the air is a special way they find food or look for places to lay their eggs.

Description

Hoverflies come in many different sizes. Some are very small, like Paragus tibialis, which is only 3–5 mm long. Others, like Criorhina nigriventris, can be up to 20.6 mm long. They can look very different too — some are slim and thin, while others are big, hairy, and have yellow and black bodies. All hoverflies have just one pair of wings, with the other pair acting like balancing organs.

Many hoverflies have bright colors, like spots and stripes, which make them look like wasps or bees. This helps protect them from birds that might want to eat them. Even though they look like stinging insects, hoverflies are harmless to humans. Adult hoverflies mostly eat nectar and pollen from flowers, which is why they are often seen hovering around them.

Reproduction and life cycle

Hoverfly maggots, also called larvae, eat different foods from the adults. Some maggots eat decaying plants and animals, while others eat tiny insects like aphids and thrips that harm crops. These predatory maggots help farmers and gardeners by controlling pest insects naturally.

A famous example is the rat-tailed maggot from the drone fly. It lives in dirty water and has a long breathing tube at its end. These maggots are sometimes used for ice fishing. Very rarely, hoverfly maggots can accidentally get into food and cause problems for people.

Evolution

The oldest known fossils of hoverflies come from the Eocene period, found in places like the Florissant Formation, Green River Formation, and Baltic amber. Scientists have also discovered an ancient genus called Prosyrphus in Late Cretaceous Burmese amber, which seems to be an early relative of modern hoverflies. These fossils help us understand how hoverflies have changed over millions of years.

Main article: Syrphidae

Distribution and habitat

Hoverflies are found almost everywhere except in extreme deserts, the far north tundra, and Antarctica. Some species live in water, while others live on land near plants or flowers. Many hoverflies enjoy visiting flowers for food, where they drink nectar and collect pollen.

Certain hoverflies prefer specific regions; for example, the American hoverfly is common in North America, and the common hoverfly is found in Australia and New Zealand. Some hoverflies even live inside nests, such as in bumblebee or ant nests, while others are found in decaying plant material.

Pollination

Hoverflies are important pollinators of flowering plants in many ecosystems worldwide. They visit many wild plants and agricultural crops, and are often considered the second-most important group of pollinators after wild bees. While bees can carry more pollen, hoverflies may visit flowers more often.

Hoverflies vary in their flower preferences. Some visit many types of plants, while others prefer just a few. Many hoverflies like white and yellow flowers and can find them using smells as well as sight. Some orchids even trick hoverflies into pollinating them by smelling like aphids or by having a yellow color that attracts the flies.

Systematics

Main article: Genera of Syrphidae

Hoverflies belong to the insect family Syrphidae, which includes many different types of flies. Scientists have studied and named many genera, or groups, within this family to better understand how these flies are related to each other. These flies are an important part of nature, helping to pollinate plants and control pest insects.

Relationship with humans

Hoverflies, also known as adult syrphid flies, help plants by spreading pollen while they feed on nectar. Many hoverfly larvae eat harmful insects like aphids and leafhoppers, which can spread diseases such as curly top. This makes hoverflies important in biocontrol, a natural way to reduce pest numbers. Gardeners sometimes plant flowers like Alyssum spp., Iberis umbellata, statice, buckwheat, chamomile, parsley, and yarrow to attract these helpful insects.

Some hoverfly larvae live in wet places like manure and compost, where they help clean and filter water. The island of Runmarö in the Baltic Sea is a special place for hoverflies, where one person collected many different kinds of these interesting insects.

Identification guides

Several helpful books and guides can assist in identifying hoverflies. One useful guide is "Field Guide to the Flower Flies of Northeastern North America" by Skevington and others, which covers many species found in that region ISBN 9780691189406. Another guide, "British Hoverflies An Illustrated Identification Guide" by Stubbs and Falk, includes many species and helps with identification using detailed keys and illustrations ISBN 1-899935-05-3.

Additional resources include "Hoverflies of Northwest Europe: Identification Keys to the Syrphidae" by van Veen, and a key to the genera of Nearctic Syrphidae by Miranda and others doi:10.3752/cjai.2013.23. For those interested in hoverflies of Britain and North-west Europe, "Hoverflies of Britain and North-west Europe: A photographic guide" by Bot and Van de Meutter offers many photographs to aid identification ISBN 978-1-3994-0245-3].

Regional lists

Here are some lists of hoverfly species from different places:

• List of hoverfly species of Great Britain
• List of the Syrphidae of Ireland
• List of flower flies of New Zealand
• List of the flower flies of North America
• Syrphidae of New York State