Water flea Daphnia atkinsoni, photographed by Jan Michels, Department of Functional Morphology and Biomechanics, Institute of Zoology, Christian Albrecht University of Kiel, Germany.

This specimen has a “crown of thorns,” a defensive trait induced in offspring only when the parents sense chemical cues released by one of their main predators, the tadpole shrimp Triops cancriformis. The water flea’s exoskeleton (exterior structure, green) and subcellular details within the organism (nuclei – tiny blue dots) are both visible.

First prize in the Olympus BioScapes Competition.