A Butterfly With 15 Kinds Of Light Sensors In Its Eye

Butterflies typically have 6 or more types of light-sensing cells, but scientists recently discovered found one swallowtail species that has at least 15; the record among insects. There are discussions of animal sensing and light receptors.
https://kids.frontiersin.org/article/10.3389/frym.2017.00070

This article is from Frontiers for Young Minds, a project of the Frontiers research journal. It asks scientists to re-write their research papers at a middle school level — and then has middle or high school students serve as the editors! These articles are good, grade appropriate sources of information for students.