Mayfly, scientifically known as the order ‘Ephemeroptera‘ are incredible little insects, found in fresh water environments all over the world. These delicate creatures are like nature’s fleeting artwork, here today and gone tomorrow. With species found worldwide (except Antarctica), they belong to a group of insects that have been around for a very, very long time. Some accounts suggest they have been here for over 300,000,000 years, that’s 100 million more than the dinosaurs!
Within the Ephemeroptera order, there are 3 suborders and 5 superfamilies, and within these there are 42 different families known around the world. The taxonomy breaks down further to include over 400 genera and over 3000 species. That is one massive family tree!
These little natural beauties have a long cultural significance with humans, and are well documented in art, and writing throughout time.
Appearance & Characteristics of Mayfly
Mayflies are tiny, with most of them measuring between 0.5 to 3 cm in length. They don’t weigh much either, as light as a feather! Their standout features? Two long, thread-like tails and transparent wings that can look like they are delicately assembled, like blank, stained glass windows. These features are ancient traits that were perhaps present in the first flying insects, millions of years ago.
Other mature features include large, compound eyes and short antennae. During the first ‘nymph’ stage of a mayflies lifecycle, they have a wingless, aquatic form and they can spend the vast majority of their lives in this stage.
When mayflies mature into adults, they usually do this with synchronicity across all the nymphs in a hatch. That can be thousands of flies, all taking off together, and it is an incredible sight to see. A sky filled with life and the dance of the mayfly. For some, this will start at dawn or dusk, and due to their short lives in their mature stage, it only lasts for a day or two before the dance is over.
Distribution – Location and Habitat
Mayflies can be found all over the world, from North and South America to Europe, Asia, and Africa. The only continent you won’t find them, is on Antarctica. The biggest diversity of species can be found in the Neotropical realm, across South America, and tropical regions of Central America and the USA – specifically the southern tip of Florida.
There are fewer species in the Holarctic biogeographical realm, which is made up of most Northern Hemisphere countries north of the Neotropical realm. Although there are fewer species here, those that do live in the Holarctic realm live in very large numbers. Oceanic islands, such as those around French Polynesia and the South Pacific archipelago, tend to have very few species present.
They are particularly abundant in freshwater habitats, like rivers, streams, ponds, and lakes. The presence of mayflies is often an indicator of clean water and a healthy ecosystem, as they are sensitive to pollution.
The Lifestyle & Behaviour of Mayfly
These insects lead a life of mystery. They spend most of their lives underwater as nymphs, only to emerge, spread their wings, and fly for a very short time. It’s like once they are able to leave the water, they are in a rush to experience everything, before their impending end arrives. To live a life in a day!
For nymphs, they are fully aquatic, and go through many molts before they reach their mature form. In the early larval stages, they may be absent of gills, but in most nymph stages, they display gills in one form or fashion, allowing them to breathe and move freely in the water.
As mature flies, they don’t live long. Their entire purpose in life is to reproduce. When this task is done, so is their purpose in life and they soon die off.
In some areas, the swarming of a mayfly hatch taking flight is a tourist attraction. They can be so massive as to appear on radar, or to create severe transport delays. It can be magnificent to witness nature take flight in such a synchronous, mesmeric dance.
Diet & Nutrition of Mayfly
Underwater as nymphs, the juveniles munch on a mixture of algae, detritus, and other tiny water plants or creatures. They have tiny mouthparts to help them eat. But once they become adults and fly, they can’t eat anymore. Adult mayflies don’t have mouths, and when they reach this mature stage, their eating days are over.
Mayflies have a unique love story. They’re oviparous, laying eggs in water. Males dance in the air to attract females, and after mating, females lay hundreds to thousands of eggs! These eggs hatch into nymphs, which grow and eventually become adults.
The life cycle of mayflies is unique and consists of several stages:
- Egg: The life of a mayfly begins as an egg, which is laid underwater. These eggs can take anywhere from a few days to several months to hatch, depending on the species and environmental conditions.
- Nymph: Once hatched, the mayfly enters its nymph stage. This is the longest stage of its life, lasting anywhere from a few weeks to several years. During this time, the nymph will molt several times as it grows.
- Subimago: This is a brief transitional stage between the nymph and the adult. The subimago, or dun, is a winged form but is not yet sexually mature and can’t fly yet. This stage can last from a few minutes to a few days. They actually have two molts in their winged adult forms, which makes them unique in the insect world. They can only take flight after their second adult molt.
- Imago: This is the final and adult stage of the mayfly. Also known as the spinner, the imago is sexually mature and its primary purpose is to reproduce. Once mating has occurred, the adult mayflies die within a short time, completing their short-lived cycle.
Lifespan of Mayfly
Their name might give it away, but mayflies live for a very short time. Some only live for a few hours as adults! But as nymphs, they can live for months to years, depending on the species.
Predators & Threats to Mayfly
Being small and delicate, mayflies have many predators. Fish, are the most abundant predator they have. Many freshwater fish, such as trout and bass, feed on mayfly nymphs and adults. In fact, the emergence of adult mayflies from water bodies can trigger feeding frenzies among fish.
Birds like swallows and swifts, often feed on adult mayflies during their brief flights, and frogs and salamanders might prey on mayfly nymphs in the water. Other competitors such as dragonflies and water beetles are also known to eat the immature stages of mayflies.
But their biggest threat? Pollution, environmental and climate change. Here are some of the primary threats they face:
- Water Pollution: Mayflies are particularly sensitive to water pollution. The presence of chemicals, heavy metals, and other pollutants can be detrimental to their survival. As a result, they are often used as bioindicators to measure the health of water bodies.
- Habitat Destruction: The destruction of freshwater habitats, whether through urban development, agriculture, or other human activities, poses a significant threat to mayflies. The loss of suitable habitats can lead to a decline in their populations. As mayflies are involved in the processes of primary production and bioturbation, when this happens there is a wider effect on their ecosystem, particularly felt by other species that rely on the mayfly as a food source.
- Climate Change: Changes in temperature and precipitation patterns can affect the life cycle of mayflies. Warmer temperatures might lead to faster development but could also affect the availability of food sources. Warmer conditions can also lead to water sources drying up, or becoming congested with algae and weeds. The true impact of climate change will continue to be observed as it unfolds.
- Invasive Species: The introduction of non-native species can disrupt the ecosystem balance. Some invasive species might prey on mayflies or compete with them for food.
Population and Conservation
While mayflies as a whole are not listed as endangered, one species, the large blue lake mayfly is listed as ‘Endangered’ on the IUCN Red List, while two other species – the Pecatonica River Mayfly and Pentagenia robusta are both listed as extinct.
No other species is listed on the Red List, but that doesn’t mean they should be ignored. The presence or absence of mayfly in a water body can indicate its health. Since they are sensitive to pollution, a decline in mayfly populations can signal deteriorating water quality. In some regions, specific species of mayflies might be at risk due to localized threats.
Conservation efforts often focus on preserving clean water habitats and reducing pollution to ensure the survival of these delicate insects.
5 Fun Mayfly Facts for Kids
- Mayflies have been around for over 300 million years!
- Some mayflies don’t even have mouths as adults!
- Some species are also called ‘dayflies’ because of their short adult life.
- Mayflies can ‘dance’ in the air. It’s their way of attracting a female mate!
- There’s a festival in the US called the ‘Mayfly Festival’. It celebrates these amazing insects!
Significance to Humans
Mayflies have various significance to humans, and can give a good indication about the health of an environment:
Fishing: They are an essential food source for many freshwater fish, making them a crucial component of fly fishing.
Ecological Indicator: Their presence or absence can indicate the health of freshwater ecosystems.
Cultural Significance: In some cultures, the brief life of the mayfly is seen as symbolic of the transient nature of life.