Part 2: (3/8/24): How do animals fake each other out, and why?

[Dan Russell]

Mussels are more than you might think... 

... in Wednesday's Challenge I asked:  

 

1. Given that mussels are fairly quiet and sessile creatures, do they ever try to do some kind of fakery in their appearance?  If so, why?   

When you think about animals doing fakery, the word that should spring to mind is (as SRS Regular Reader Krossbow pointed out) is mimicry.  

It's true that mussels are stationary for most of their lives, but they're not static.  They can open their shells and do stuff.  Plus, they've been evolving for around 500 megayears and are capable of quite rapid evolutions!  

My first query was: 

     [ mussels mimicry ] 

which quickly led me to find this result from PBS (the Nature series): 

For example, females in the mussel genus Lampsilis have an extension of the mantle tissue that strikingly resembles a small fish. The mussel displays this tissue outside its shell between the valves and twitches it repetitively to attract its predaceous fish host – like a fishing lure.

Be sure to check out their video (especially at :52)  

That's a wonderful example of mimicry which you can also see in
this video with a slightly different camera angle:  

This is one of those cases when knowing just the right word works really well.  In this case, knowing the vocabulary word mimicry makes a huge difference.  This particular freshwater mussel, Lampsilis reeveiana, releases a huge cloud of mussel larvae (video), known as glochidia, some of which then attach themselves to the gills of fish that dares to try and eat the fake fish lure.  (See the glochidia attach themselves to fish gills in this video.) 

But that's not all... There's much more to discover, and that's the second part of this 3-part Challenge.... 

2. In addition to a fake fish lure, there are OTHER mimic devices that freshwater mussels use.  Can you find them as well?  (Think beyond a minnow sitting on top of the mussel shell.) 

As always, let us know what you find and what you did to find it!  

(Warning: These next couple of mimicry mechanisms are wild!)  

 

Keep searching.  

--

Daniel M. Russell 

Check out my new book:  The Joy of Search (MIT Press, Winter, 2019) 

Available in fine bookstores (and online) everywhere.