Close-up on the third eye What looks like a sparkling gemstone is the median ocellus of a wild bee – one of three simple light sensors on its head. Unlike the large compound eyes that deliver images, ocelli only detect brightness and the polarization of light. They help the bee instantly recognize the horizon, stabilize flight attitude, and even “see” the sun on cloudy days – perfect for daring maneuvers between flowers. In many insects, ocelli are also linked to the internal clock and support navigation according to the circadian rhythm. Three tiny dots, massive superpower Sources: Rossel, S. (1989). Polarized Light in Insect Vision. In: Comprehensive Insect Physiology, Biochemistry and Pharmacology. Warrant, E. J. (2017). The remarkable visual abilities of nocturnal insects. Journal of Experimental Biology. Labhart, T. & Nilsson, D.-E. (1996). Ocelli in insects: Structure and function. Arthropod Structure & Development.

Dung beetle, Geotrupes spiniger. Fascinating hairs on the eye of this amazing beetle.