Noon Fly: All You Need to Know

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Noon Fly (Mesembrina meridiana)

The Noon Fly, scientifically known as Mesembrina meridiana, is a species of fly that belongs to the Muscidae family.

Predominantly found in various parts of Europe, the Near East, and some regions of Asia and North Africa, this fly has certain distinctive features that set it apart from other fly species.

While its name might suggest a relationship to the time of day, it’s more about its behavior and habitat.

This article delves into the specifics of the Noon Fly, providing a comprehensive overview for those interested in understanding this insect better.

Noon Fly (Mesembrina meridiana)
Noon Fly (Mesembrina meridiana). Source: iNaturalist, Author: Michael Knapp, License: CC by 4.0 Deed

Physical Description

The Noon Fly measures between 9–13 millimetres (0.35–0.51 in) in length.

It boasts a stout body that is predominantly shiny black in color. This black hue covers both its thorax and abdomen, and the body is uniformly covered with black hair.

One of the most distinguishing features of the Noon Fly is its wings.

The base of its wings exhibits a striking orange coloration, which contrasts vividly with its black body.

Additionally, this orange hue can also be observed on its feet and face, giving it a unique appearance among flies.

When observing the Noon Fly, it’s essential to note certain features that help in its identification. 

The fly’s eyes are bare, devoid of any hairiness, and the space beneath the eyes, known as the cheeks, is covered with fine yellow short hairs.

The space between the orbits (eye regions) is wide and black. While its antennae and palps are black, the arista (a long bristle on the antenna) is yellow.

These specific features can aid in distinguishing the Noon Fly from other similar species, such as Mesembrina resplendens and Mesembrina intermedia.

Rinderfliege, Mesembrina meridiana
Rinderfliege, Mesembrina meridiana. Source: ApdeCC BY-SA 3.0, via Wikimedia Commons

Habitat and Distribution

The Noon Fly has a broad distribution range, being widespread in most of Europe, the Near East, and the eastern Palearctic realm.

This includes countries and regions such as Russia, Mongolia, and China. Additionally, its presence is also noted in North Africa.

In terms of habitat, the Noon Fly is commonly observed in hedgerows and woodland edges. 

These environments provide the Noon Fly with the shelter and resources it requires for its daily activities and lifecycle.

One of the characteristic behaviors of this fly is its penchant for basking in sheltered, sunny spots.

This is often observed during the warmer parts of the day. Furthermore, the Noon Fly has a specific dietary preference, often feeding on plants known as umbellifers, which are a type of flowering plant.

Biology and Life Cycle

The biology of the Noon Fly is fascinating. It exhibits an ovoviviparous nature, which means that its eggs hatch either just before being laid or within an hour after deposition.

This is a unique reproductive strategy that ensures a higher survival rate for the offspring.

A female Noon Fly will lay up to five eggs during her lifetime. Each of these eggs is deposited in different cow dung, ensuring a diverse environment for the larvae to thrive.

The adult Noon Flies are most active between the months of late April and late October.

Mesembrina meridiana
Mesembrina meridiana. Source: Jan EbrCC BY 4.0, via Wikimedia Commons

This period aligns with the warmer months in most of their habitats, especially in cattle-rearing areas where they are most commonly found.

When it comes to their mating habits, Noon Flies are observed to mate in cow or horse dung. 

Post mating, their dietary habits shift towards feeding on the nectar and pollen of flowers. They have a particular preference for flowers from the Apiaceae family.

Additionally, they are also known to feed on overripe berries, diversifying their diet.

The larvae of the Noon Fly have a carnivorous diet. Instead of feeding on the dung where they are born, they prey on other fly larvae present within the same dung.

This predatory nature ensures they have ample nutrition for growth and reduces competition for resources within the dung.

Importance in Ecosystem

The Noon Fly plays a pivotal role in the ecosystem, especially within agricultural grassland ecology.

Grasslands, which are often used for cattle rearing, benefit from the presence of the Noon Fly in several ways.

One of the primary ecological roles of the Noon Fly is its contribution to controlling the populations of other coprophagous insects.

Coprophagous insects are those that feed on dung, such as dung beetles.

By laying their eggs in dung and having their carnivorous larvae feed on other fly larvae within the dung, Noon Flies naturally regulate the number of other dung-feeding insects.

This control is crucial, as an unchecked population of coprophagous insects can lead to various ecological imbalances, affecting the decomposition rate of dung and the nutrient cycle in grasslands.

Noon Fly
Noon Fly. Source: Flickr, Username: Julie from Wexford

Are Noon Flies Dangerous?

Do Noon flies bite?

A common question is whether Noon Flies bite. There’s no evidence to suggest that Noon Flies bite humans.

Their primary diet consists of nectar, pollen, and, in the case of larvae, other fly larvae within dung.

Are Noon Flies harmful to humans? 

The simple answer is no. They do not possess any venom, nor do they transmit diseases to humans.

Their presence in cattle-rearing areas is more beneficial than harmful, as they play a role in controlling other insect populations.

Frequently Asked Questions

How big are noon flies?

Noon Flies typically measure between 9–13 millimetres (0.35–0.51 in). Their size, combined with their distinctive coloration, makes them easily distinguishable from many other fly species.

What is the Mesembrina Meridiana habitat?

The primary habitats of the Noon Fly, or Mesembrina Meridiana, are hedgerows, woodland edges, and cattle-rearing areas. These environments provide the necessary resources and conditions for the Noon Fly to thrive.

What is the smallest type of fly?

The Noon Fly does not hold the title of being the smallest fly. At 0.4 millimeters (0.016 inches) in size, Euryplatea nanaknihali is the tiniest fly in the world. Due to its small size, the fly is unable to navigate even small air currents.

What are the orange and black flies in the UK?

In the UK, several flies exhibit orange and black coloration. However, the Noon Fly is one of the most prominent flies with these colors.

Its distinctive orange wing bases and black body make it easily recognizable among the myriad of fly species in the region.


To summarize, the Noon Fly, scientifically termed as Mesembrina meridiana, is a distinctive species prevalent in parts of Europe, the Near East, and certain regions of Asia and North Africa. 

Characterized by its unique size of 9–13 millimetres and a striking combination of black and orange coloration, it predominantly thrives in hedgerows, woodland edges, and cattle-rearing areas.

Its ovoviviparous reproductive nature and carnivorous larvae play a crucial role in controlling the population of other dung-feeding insects, ensuring ecological balance in grasslands.

As a pivotal component of the agricultural grassland ecosystem, understanding and appreciating the Noon Fly underscores the importance of even the smallest creatures in maintaining ecological harmony.

Reader Emails

Letter 1 – Noon Fly from UK

gold fly
Location: la12 8ht, UK
December 14, 2010 5:05 pm
i found this fly several months ago, i have searched thorugh several books and the internet but cannon find the name of the species and wondered if you could help, if it is an unidentified species how to i go about registering it? i found this fly in the summer
Signature: James Gill

Noon Fly

Dear James,
This is not the ideal vantage for identification purposes, but we decided to give it a try.  Upon browsing through the images of living specimens on the Dipterists Forum we found an image of
Mesembrina meridiana that closely resembles your fly. 

Searching that name led us to the Natural England website that identified it as the Noon Fly in the family Muscidae and provided this information:  “This is a large, shiny black fly with conspicuous yellow bases to its wings. Noonflies can be found sunning themselves on logs, fences, tree trunks, walls or sunny paths where their colourful wing-bases may make them conspicuous. 

The larvae develop in cattle dung. Although widespread and common, these flies are normally only to be found in fairly rural gardens or others which are near places where cattle are reared.”  The Ecology of Commanster website has some marvelous images of this species.  The family Muscidae contains the House Fly and kin.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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