Butterflies are bright-colored and beautiful flying insects with long wings compared to their body size. The eyes are the significant body parts that help organisms survive and overcome the challenges around their living and feeding sites.
Do Butterflies Have Eyes? Butterflies have two compound eyes made of thousands of mini-eyes, such as layers of individual lenses and visual chambers or ommatidia. They are located on both sides of the head, and the number of eyes varies with the age, as caterpillars have 10-14 eyes. Moreover, they have monocular vision with 344-360 degree angles and can see many colors in the 245-600 nm range, including ultraviolet radiations.
They fly from one place to another with their sharp vision in daylight and are adapted to take long flights in the daytime. The vision quality varies among the species and the time of the day. They have different adaptations and rely on them for survival, such as eyesight, hearing, and sensing the slight changes in their habitat.
How many eyes does a butterfly have?
They have two eyes and consist of many individual vision chambers called compound eyes. They contain approximately 12,000-17,000 mini eyes, each having a lens, a single rod cell, and three cone cells.
They can see many things in different directions simultaneously, and their brain perceives the image from each chamber.
However, scientists are not sure whether the butterfly brain collects and combines the 17,000 images into a single image or forms a mosaic image.
Once, I attended a seminar about the anatomical features and science behind them for people who love to study and know about different species.
I learned about the vision and anatomy of butterfly eyesight. The entomologist addressing the audience said these insects face some downsides of compound eyes, such as various lenses causing acuity loss.
Moreover, he explained that thousands of ommatidia act as individual eyes and can see various color patterns and objects that are not visible to the human eye.
In addition, I was surprised when he said the number of eyes varies with the age and life cycle of these insects, as the caterpillars have different numbers of sight tools.
The caterpillars have 10-14 eyes, depending on the species, and they develop into two when they complete the metamorphosis, as it is made of thousands of lenses.
He said some caterpillars have twelve eyes, such as six on both sides, and are arranged in a circular pattern around their face.
What type of eyes do butterflies have?
They have small eyes with excellent day vision and cannot see better in the dark. Its color varies with species as some species have black and brown eyes, while others have whitish or gray ones.
One of my friends told me he saw a butterfly with marble and orange tip eyes. He was surprised to see it. I asked him the reason behind it, and he said the color pigmentation in eye tissues causes the variation in shade among different species.
He said some species also have green shade lenses, and the shade of green varies among species. A few weeks ago, I also saw a butterfly with a metallic lens, creating a striking color appearance when sunlight fell on the lens.
Its color helps to camouflage and perform different vision perception purposes. Moreover, their eyes’ shape and body size also differ with species.
They have spherical sight tools, and the ommatidia are in a hexagonal pattern. These ommatidia are arranged close to each other and appear like a single lens from a distance.
The shape and size of the head also determine the exact eye size, but the average diameter varies between 20-35 micrometers.
Moreover, the larger the species, the larger the eyes. It is difficult to estimate their eye size from a distance because they are so small that you cannot notice them.
However, its size does not affect their visual perception because some small-sized species have excellent vision despite their small body size.
Why do butterflies have eyes?
They use their eyesight to navigate and fly to different places to forage and find mates.
They cannot detect their host plants and flowers that are beneficial and provide more nectar. Therefore, they rely on their vision to reach particular food sources.
Moreover, they select particular mates from their wing colors and patterns and cannot choose the mating fellows without eyes and vision.
They protect themselves from predators using their eyesight because they would be more prone to attacks without sharp and broad vision.
They navigate the routes while migrating and traveling from one place to another. Therefore, they cannot survive without eyes, and it is one of the most significant orangs in their small-sized bodies.
Where are the eyes on the butterfly?
Butterfly eyes are located on both sides of the head and can see around their habitat without problems. This location helps them see better when flying because they are present on top of their head.
Moreover, I often hear a misconception from people that these flying insects have eyes on their wings. It is not true because these are the eyespots, not actual seeing tools.
They have eye-like patterns on their wings to startle the predators but cannot see with them. These patterns differ in color, size, and shape, as owl butterflies have big brown eyespots on their wings.
These patterns also make predators think their heads are at other locations, and they flap their wings to deter predators.
In addition, peacock butterflies also have prominent eyespots on their wings, and these spots have shiny centers to confuse predators.
How good is a butterfly’s eyesight?
Butterflies have nearsightedness and monocular vision. They can see the colors but cannot observe the depth and distance of objects and patterns.
I also studied the visual perception of many insects in my entomology research project and came to know many interesting facts about them.
I was impressed with their visional adaptations of 344-360 degree broad vision and can see the predators at their back.
I also read that their broad vision is an exceptional feature that many animals, birds, and insects lack, and they survive many difficult situations.
Tiny fractional movements in their head can change the amount of light striking the receptors, and they detect the slight changes around their habitat.
They have a flicker vision frequency of 150 images per second, which is far more than humans and many animals, and help them assemble the mosaic images that the compound eyes form.
Moreover, they can see one centimeter to 200-650 feet away with a sharp focus because the ommatidia are of short focal length.
What colors can butterflies see?
Butterflies have six to nine photoreceptors and can see many colors, including red, blue, green, yellow, and more shades.
Moreover, they can also see the ultraviolet patterns on the flowers and wings of mating fellows. They also communicate with the visional patterns on their wings and identify the species members.
They can see the color range from 254-600 nm, including UV radiations, which are invisible to humans. The photoreceptors help them find the nectar-rich plants and the host plants to lay eggs.
Swallowtail butterflies have the exceptional feature of having fifteen different photoreceptors, which help them in mating purposes and pollination.
Do butterflies have eyelids and eyelashes?
They do not have eyelids and eyelashes because they do not sleep; therefore, there is no need for eyelids. They roost at night but do not close their eyes to sleep.
I worked in an entomology department for a few months, and a senior colleague told me that he never experienced a butterfly sleeping because they lacked eyelids.
Moreover, he said there is no role of eyelashes, as they keep their eyes open all the time. They can detect changes in motion and have other ways to protect their eyes without the need for eyelashes.
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