Readers Question: mantis eye color

Angie send me the following message and question:

Thank you for this site it’s so informative. I myself am not much of an insect fan, but we had this mantis in our garden for several months this summer. It’s been fun observing him, then we had a sudden temperature drop this week and decided to bring him in so he wouldn’t die (it snowed). We have a nice enclosure for him, he’s been eating well and I do mist the plants in the enclosure for him to drink from. I’m just curious about the color of his eyes. When he was outside they were green, now they seem to have gotten darker. I work so I only see him in the early mornings and late evenings when I get home. In the garden we only observed him in sunlight as he would hide out of sight at sunset. Is this color change normal due to lower light, or is this a sign that something is wrong?

It’s a close observation and I’m glad to say it’s completely normal. The eyes of a mantis will differ in color depending on the light conditions. Pigments in the eyes of a mantis will gather when there is low light or darkness. You can see this around half an hour after the mantis is placed in the dark. In the light the pigments will disappear again leaving the eye light-colored.

In different mantis species the color of the eye changes. In the Orchid Mantis Hymenopus coronatus the eyes can be white or light-pink in bright light conditions and deep purple in darkness. It’s a stunning difference! Mantises with green eyes will change the color between light green and dark green, almost black. Mantises with brown eyes like the Dead Leaf Mantis Deroplatys desiccata will develop completely black eyes in darkness.

The eye color probably changes to facilitate better vision for the mantis. It is unclear how the pigmentation helps the mantis in its ability to see better.

There is one condition, an illness, in which mantises get dark eyes. This is not caused by pigmentation and it does not depend on light conditions. It’s a permanent black or dark spot in the middle of the eye and it does not move position when you look at it from different angles. It is damage to the surface of the eye caused by scratching the eyes of the mantis against the glass or plastic of its container. Sometimes a mantis can get obsessive trying to approach or catch a prey that is on the other side of the glass container. While trying to approach the prey the mantis brushes its eyes back and forth against the glass, damaging the eyes. When the wound gets infected it turns black. This problem is pretty severe because the eyes will not recover and vision is lost in the area where the wound is. If you see your mantis brushing it’s head and eyes against the container, make sure to remove the object it is after or place the mantis in a net cage. This will prevent any other damage to your beautiful pet mantis.