The eyes of many arthropods consist of a large number of so-called ommatidia. Sometimes the animals seem to follow you with its "pupil" wherever you go, but this is in fact not a pupil, but just an optical effect caused by the tube-like shape of these ommatidia. The ommatidia that are aligned with you will turn dark because you can't see the walls of these ommatidia and they can therefore not reflect any light back to you. In a way, you are looking directly into the eye of the animal! These spots are aptly called pseudopupils.
[ situation 1 || situation 2 ] ⇛ A pseudopupil in a moth (2016-07-09)
[ situation 1 || situation 2 || situation 3 ] ⇛ A pseudopupil in a froghopper (2016-08-07)
[ situation 1 || situation 2 ] ⇛ A pseudopupil in a fly (2016-08-20)
Pseudopupils in a froghopper. In this case, the different positions of the pseudopupils in both eyes can be seen (2016-08-20)
[ situation 1 || situation 2 ] ⇛ A pseudopupil in a leafhopper (2016-08-20)
[ situation 1 || situation 2 || situation 3 ] ⇛ A pseudopupil in a mayfly (2016-09-18)
Pseudopupils in a leafhopper (2017-05-26)
[ situation 1 || situation 2 ] ⇛ Pseudopupils in a leafhopper (2017-07-29)
[ situation 1 || situation 2 ] ⇛ (2020-07-31)