Flies belong to the insect order Diptera, along with blowflies, mosquitoes and horseflies. They appeared about 250 million years ago and since then they have evolved in a surprising way. Today, flies are the second most abundant insects on Earth, with Coleoptera being the first. They are distributed throughout the world and can be found in almost all climates and environments, from cold areas to deserts and in tropical forests, as well as at high altitudes. They live at sea level or in the high mountains and their lifestyle can be very varied, with both free-living species, ecto or endoparasites and commensals.
If you want to continue reading about this peculiar group of insects and find out how flies see, continue reading this article on our site and we'll tell you all about it.
Characteristics of flies
Flies are part of the Muscidae family, and like all Diptera, their body is divided into tagmas (regions or segments of the body), in addition to other characteristics:
- Body of flies: they have a stockier body, short legs and agile flight, compared to mosquitoes, for example. In addition, like the rest of the insects, flies have three segments, which are the head, thorax and abdomen.
- Mouth and eyes of the fly: on the other hand, they have compound eyes and their mouth organ is formed by a series of adapted appendages for all kinds of feeding, such as piercing, sucking or licking, depending on the species and its way of life.
- Wings: they have a pair of wings that are inserted in the thorax, unlike the rest of the insects that have two, since the second pair is reduced to “rockers” or “h alteres”, which help them stabilize their movement.
- Patas: Its three pairs of legs are also located on the thorax and are provided with sticky pads with which they can move on all types of surfaces such as glass windows and even walking "upside down".
- They smell through their legs: throughout the entire body, they have sensory units in the form of silks that allow them to smell and taste surfaces or food, as well as on their paws, these sensory silks that serve the same purpose.
- Fly life cycle: they are holometabolous insects, that is, they have four phases during their development, which are the egg, the larva, followed by the pupa and the adult.
- Reproduction: the adult can lay its eggs near decomposing organic matter, although some species are ovoviviparous, meaning that the Eggs hatch inside the mother and then the young emerge as larvae.
For more information, you can consult this other article on our site about Characteristics of insects.
Types of eyes in flies
In flies, the eyes are located in the mobile head, occupying a large portion of it. They have two compound eyes located dorso-laterally, and are made up of several units (receptive units or ommatidia) that have a hexagonal shape and converge together to form acomposite image , similar to a honeycomb. In most species there are also three small dorsal ocelli (simple eyes) on the head that do not focus on objects or capture images, since their function is to perceiver different intensities of light Each ocellus has a lens (cornea) and a layer of photoreceptor cells (rods).
Compound eyes lack a central lens, which does not allow them to have a good resolution of the images they see. However, they are able to perceive rapid movement and see solid angles. Their eyes are located apart from each other or in some species they can be together. In the case of the males of some species they can touch each other and in the females, however, they are smaller and are separated. Compound eyes can be of two types:
- Appositional: where each ommatidium fixes segments of an image to later merge them in the brain. Vision resolution increases with the size of the animal.
- Overlay: They are divided into refractive and reflective. In the former, the retina is responsible for capturing a total image of the light focused by each of the ommatidia, and in the latter, each of the ommatidia in turn takes a total image of the light it focuses.
In case you are also interested, in this other article we inform you about How to drive away flies?
Do flies see in slow motion? - Vision of flies
These insects see thanks to a primitive but effective mechanism based on electrical impulses The eyes record static images and send them to the brain in the form of of flashes at a certain rate per second, and in the case of flies, they can send up to 250 flashes per second, compared, for example, with a human, which is 60 flashes per second. So it is that flies have the ability to observe the movements of their environment at finer scales than humans.
These animals have an angle of vision of almost 360º and have the ability to capture the movements of their surroundings much more slowly, as a slow motion”, this is why his movements are very fast and thanks to the fact that his brain can process several movements at the same time in a fraction of seconds.
They have thousands of neuronal cells that interconnect in their brain and receive information thanks to the photoreceptors in their eyes and react by increasing or decreasing their intensity. On the other hand, they have difficulty seeing colors, they can only see a couple of different wavelengths of light causing some colors to not appear at all, as in the case of red. However, studies have shown that flies are repelled by the color yellow and on the contrary, they are attracted to the color blue.
If you liked this article about how flies see, you may also be interested in this article about The most beautiful insects in the world.
