{"id":1706,"date":"2022-03-24T17:56:29","date_gmt":"2022-03-24T17:56:29","guid":{"rendered":"https:\/\/interestinganimalfacts.com\/?p=1706"},"modified":"2022-03-25T22:20:33","modified_gmt":"2022-03-25T22:20:33","slug":"how-many-eyes-does-a-fly-have","status":"publish","type":"post","link":"https:\/\/interestinganimalfacts.com\/how-many-eyes-does-a-fly-have\/","title":{"rendered":"How Many Eyes Does A Fly Have?"},"content":{"rendered":"\n

You have probably heard someone tell you that flies have millions of eyes, which helps them to see far more, and perceive motion far faster than humans can. <\/p>\n\n\n\n

However, this isn’t totally the reality – flies don’t have ocular systems like we do – they have two separate systems, one to sense light and once to sense motion.<\/p>\n\n\n\n

In this article, we will take a closer look into the visual system of a fly, and answer once and for all ‘how many eyes does a fly have’. Read on to find out more about fly’s eyes. <\/p>\n\n\n\n

How Many Eyes Does A Fly Have? <\/strong><\/h2>\n\n\n\n

It is a common urban myth that flies have millions of eyes. However, this isn\u2019t technically true. <\/p>\n\n\n\n

If you have ever seen a fly up close, you will be familiar with their two, large bulbous and glittering ‘eyes’ on the side of their head. <\/p>\n\n\n\n

These strange looking components are what’s known as ‘compound eyes’. <\/p>\n\n\n\n

Essentially, this boils down to these eyes being made up of many tiny eyes. Each of these tiny eyes is called a facet, and there are hundreds of these facets in each fly’s head. <\/p>\n\n\n\n

This means that they can see very well even though they have smaller eyes than us – which can make it difficult to catch a fly with your hands – as they can perceive motion far faster than us.<\/p>\n\n\n\n

What Is A Compound Eye? <\/strong><\/h2>\n\n\n\n

Insects have compound eyes. Compound eyes form a 3D image which is a combination of thousands of images received by thousand photoreceptors present within a single compound eye. <\/p>\n\n\n\n

The resolution of the image created is quite low compared to a single aperture eye (which is the kind of eye that we have). <\/p>\n\n\n\n

However, the compound eye gives flies and other insects a larger area of vision (so they can see motion in nearly their whole environment). <\/p>\n\n\n\n

It also gives them the ability to detect movements around them much more quickly than would be possible with a single aperture eye. <\/p>\n\n\n\n

This helps flies and other insects to respond quickly to any movement nearby. This makes it difficult to catch them, as they can detect even the slightest motion. <\/p>\n\n\n\n

Flies are often a prey animal – eaten by other animals such as bats and birds – so these compound eyes have evolutionarily developed to give them an advantage that can help them survive. <\/p>\n\n\n\n

Compound eyes are made up of lenses and receptors. There are basically two types of compound eyes: apposition, and superposition. <\/p>\n\n\n\n

Apposition eyes form several inverted images, while superposition eyes form a single image (like our eyes). <\/p>\n\n\n\n

Flies have two large compound eyes, which have been specially designed to provide them with good visions (especially when compared to the vision of other insects). <\/p>\n\n\n\n

Overall – flies have only two eyes, and thousands of eyes at the same time. As they have two large compound eyes, the number of facets in each eye is equivalent to a thousand of human eyes. <\/p>\n\n\n\n

Some flies also have ocelli eyes on the top of their head, which sense changes in light, rather than movement. <\/p>\n\n\n\n

\"How<\/figure><\/div>\n\n\n\n

How Many Lenses Does An Average Fly Have?<\/strong><\/h2>\n\n\n\n

We have two eye lenses, with each lens in each eye. Flies have a pair of compound eyes, and each compound eye consists of 4500-5500 individual lenses combined (although this is just an approximation). <\/p>\n\n\n\n

In some senses, a fly’s compound eyes are much better than humans because they have more lenses, and can perceive motions and environmental changes far faster.<\/p>\n\n\n\n

Compound eyes are very useful for insects because they help them see things better. They are made up of many tiny pieces called facets. <\/p>\n\n\n\n

Each facet sees a different part of the light coming towards the eye. They combine the information received by each facet into an image of the whole scene. <\/p>\n\n\n\n

Insects use this to determine direction, distance and speed. <\/p>\n\n\n\n

How Many Pupils Does An Average Fly Have?<\/strong><\/h2>\n\n\n\n

In a human, our iris (the colored part of our eye) can contract and relax to change the size of our pupil (the black hole in the center of our eye). <\/p>\n\n\n\n

This alters how much light can reach our retina – which protects our eyes in bright situations, and helps us see better in dark situations. <\/p>\n\n\n\n

However, flies don’t have irises, and therefore can’t change the size of the aperture in their eye. They also have no pupils. <\/p>\n\n\n\n

They therefore don’t have any control over how much light they have exposed to their retina, and this can even result in damage to their eyes. <\/p>\n\n\n\n

Overexposure to blue light can lead to eye damage and permanent blindness in older flies. This is known as futurity. <\/p>\n\n\n\n

Houseflies: How Many Eyes Do They Have? <\/strong><\/h2>\n\n\n\n

Houseflies have two types of eyes: compound eyes, and ocelli eyes. Their compound eyes are made up of thousands of tiny units called facets. <\/p>\n\n\n\n

These facets are arranged in a hexagonal pattern – and can be counted as individual eyes, giving a housefly about 3000 to 6000 eyes. <\/p>\n\n\n\n

Horseflies: How Many Eyes Do They Have? <\/strong><\/h2>\n\n\n\n

While a common housefly has ocelli eyes in addition to their compound eyes, horseflies are a little different. <\/p>\n\n\n\n

Unlike the common housefly, a horsefly doesn’t have these ocelli eyes, instead making do with larger compound eyes. <\/p>\n\n\n\n

The eyes of a female horsefly are separated by a thin black line. Male horse flies’ eyes touch each other. So, horsefly eyes aren’t only for vision, but also for telling the sex of a fly. <\/p>\n\n\n\n

Fruit flies: How Many Eyes Do They Have? <\/strong><\/h2>\n\n\n\n

Fruit flies have two main eyes that each have 750 lenses. They use two-thirds of their brains to process visual information from these eyes. <\/p>\n\n\n\n

Though most flies have black eyes, there is more variety when it comes to fruit fly eye color. You can find fruit flies with red, black, brown and white eyes. <\/p>\n\n\n\n

Final Thoughts<\/strong><\/h2>\n\n\n\n

In conclusion, flies have approximately 2,000 lenses in each of their compound eyes. These lenses are arranged in rows and columns, which create the illusion of depth perception. <\/p>\n\n\n\n

They are similar to the lenses in our own eyes, but are slightly different in that they don’t have irises to control pupil size, and they are packed tightly in a hexagon pattern. <\/p>\n\n\n\n

So, in a way – flies have both 2 to 6 eyes, and also thousands of eyes. <\/p>\n\n\n\n

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