Editing Jellyfish (section)

==== Evolution as a response to natural stimuli ====
The primary adaptive responses to environmental variation observed in box jellyfish eyes include pupillary constriction speeds in response to light environments, as well as photoreceptor tuning and lens [[adaptation]]s to better respond to shifts between light environments and darkness. Some box jellyfish species' eyes appear to have evolved more focused vision in response to their habitat.<ref name="Seymour-2020">{{cite journal|last1=Seymour|first1=Jamie E.|first2=Emily P.|last2=O'Hara |title=Pupillary Response to Light in Three Species of Cubozoa (Box Jellyfish) |journal=Plankton and Benthos Research |volume=15 |issue=2 |year=2020 |pages=73–77 |doi=10.3800/pbr.15.73|s2cid=219759193 |doi-access=free }}</ref>

Pupillary contraction appears to have evolved in response to variation in the light environment across [[ecological niche]]s across three species of box jellyfish (''[[Chironex fleckeri]]'', ''[[Chiropsella bronzie]]'', and ''[[Carukia barnesi]]''). Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance,<ref name="Seymour-2020" /> and in fact, species with more complex habitats exhibit faster rates. ''Ch. bronzie'' inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. ''Ca. barnesi'' and ''Ch. fleckeri'' are found in more three-dimensionally complex environments like [[mangrove]]s with an abundance of natural obstacles, where faster pupil contraction is more adaptive.<ref name="Seymour-2020" /> Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.

Light/dark adaptation via pupillary light reflexes is an additional form of an evolutionary response to the light environment. This relates to the pupil's response to shifts between light intensity (generally from sunlight to darkness). In the process of light/dark adaptation, the upper and lower lens eyes of different box jellyfish species vary in specific function.<ref name="O'Connor-2009" /> The lower lens-eyes contain pigmented photoreceptors and long pigment cells with dark pigments that migrate on light/dark adaptation, while the upper-lens eyes play a concentrated role in light direction and phototaxis given that they face upward towards the water surface (towards the sun or moon).<ref name="O'Connor-2009" /> The upper lens of ''Ch. bronzie'' does not exhibit any considerable optical power while ''Tr. cystophora'' (a box jellyfish species that tends to live in mangroves) does. The ability to use light to visually guide behavior is not of as much importance to ''Ch. bronzie'' as it is to species in more obstacle-filled environments.<ref name="O'Connor-2009" /> Differences in visually guided behavior serve as evidence that species that share the same number and structure of eyes can exhibit differences in how they control behavior.