Wednesday, May 30, 2012

My Favorite Symbioses

I recently finished a course called “Communicating in a Complex World” that was all about symbiotic relationships in nature.  This was an elective I picked because I wanted something out of my area of expertise (neuroscience), and because it just seemed like a cool topic.  Perhaps this is the Bay Area hippie side of me talking, but something about the idea of different living things coexisting in harmony, and actually working together to be better than they could be alone, is really beautiful.

 The course covered a lot of diverse topics, but I just wanted to share my three favorites with you.  First, though, a bit of terminology.  “Symbiosis” simply means living together, not necessarily good or bad.  What we usually refer to as symbiosis is specifically mutualism.  This is where both parties benefit.  If one benefits and the other is unaffected, it’s commensalism.  And parasitism, as we all know, is one benefiting at the expense of the other.  Those symbioses are no fun and they don’t make my list. 

1. Glowing squid

The bobtail squid hosts bioluminescent bacteria
[image from kahikai.org]

The Hawaiian bobtail squid has a very clever form of camouflage.  A nocturnal creature, it hides in the sand during the day then emerges to feed at night.  Predators watching from deeper waters look upward, searching for the dark squid silhouetted against the moonlit night sky.  To remain unseen, the bottom side of the squid lights up with a glow that mimics the light from above.  It’s the perfect adaptation.

However, unlike many other bioluminescent forms of sealife, the bobtail squid can’t produce