Pareidolia of the cute dragonfly. When our brain tricks us

A few days ago, this flying insect with a big smile came to my balcony.

And you can easily recognize some "biological" structures...

Actually, our brains are trickings us. This is a classic example of pareidolia, psychological phenomenon when our brain is recognizing the well-known patterns where there are no patterns at all.

Boring, biological explanation...

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Let's start explaining the structures from the top to the bottom:

Vertex is the structure that holds 3 simple "eyes" named ocelli. According to the latest measurements (2007) the aperture of ocelli is low and its shape is elliptical. Even more important, the refractive index of the structure is not homogeneous. This leads to the conclusion that ocelli are important for the fast recognition of the horizontal structures. In other words, during the fast, aggressive flight manoeuvres, dragonflies have the artificial horizon, just like fighter jets!

Image from Pixabay, modified

Compound eyes consist of two types of ommatidia. Those sensitive to the short wavelengths are located at the top of the head while the eyes sensitive to the long wavelengths are located at the bottom part of the eyes. Speaking in terms of the fighter jets, compound eyes represent both the observation radar and the radar that is guiding the missiles.
For me, the best part of the story came in 2015:

Exhaustive transcriptomic and genomic surveys of three dragonflies of the family Libellulidae consistently identified 20 opsin genes, consisting of 4 nonvisual opsin genes and 16 visual opsin genes of 1 UV, 5 short-wavelength (SW), and 10 long-wavelength (LW) type. Comprehensive transcriptomic survey of the other dragonflies representing an additional 10 families also identified as many as 15–33 opsin genes

You understand that we are gathering information about the world with only 3 types of "detectors" in our eyes. Just imagine the power of this multispectral imaging.

Pseudo pupil is the artefact that can be observed in the regions of an eye where the angle of ommatidia changes. Some speculate that it's the zone responsible for the best resolution, while some authors state that it's basically pointless.

Frons is the forehead. I tried to find its purpose, but in a few publications that mention it, authors just refer to it as the structure below the vertex.
Clypeus is the expression used to describe the face of insects. Also, no significant facts about that.

Labrum and mandibles really make a smile.

References:

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• Berry, Richard P., Gert Stange, and Eric J. Warrant. "Form vision in the insect dorsal ocelli: an anatomical and optical analysis of the dragonfly median ocellus." Vision research 47.10 (2007): 1394-1409. link

• Futahashi, Ryo, et al. "Extraordinary diversity of visual opsin genes in dragonflies." Proceedings of the National Academy of Sciences (2015): 201424670. link

• General guide to the anatomy of dragonflies, link

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