Notes on the venomnous predator Tripedalia, the box jelly
(diagrams from above article)
lives in complex mangrove root environ.
eats copepods that congregate in light shafts in the roots
video of Tripedalia in mangrove forest
https://www.youtube.com/watch?v=I4PFWBOm5g8
4 behaviors:
night day: as it darkens the jelly sinks to the bottom and holds onto a root to settle for night, so it doesn't get swept out of its hunting grounds. when day comes it swims back to surface
it swims towards the mangrove areas so it doesn't get washed out to sea
it detects shafts of light, when light, it decreases bell contractions and stays in light to eat copepods. if it drifts out of light it quickly increases contractions to swim back into shaft of light. is it random like bacterial chemotaxis or can it AIM back into the light shaft?
it detects vertical bars on visual field, diagonal bars a little less and horizontal bars not so much. the sharper the image, the faster the response (sharper means closer!). the response is to quickly turn around and swim away, so it doesn't collide with and injure itself on the roots.
the last 2 behaviors are mediated by camera type eyes with irises, lense and couple hundred photodetector cells. definitely responding to edges across visual field.
there is a nerve net of ~1000 neurons connecting each of their 4 eyes to muscles.
Evolution is fun!
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