"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

February 5, 2010

February 5 - Lampsilis fasciola

Mussels may seem like unassuming creatures, hanging out on the riverbed until they’re caught and served with a delicious garlic butter sauce, but many species have parasitic larvae that are crafty and downright aggressive when it comes to attracting their hosts. The larvae, known as glochida, usually can’t move around to seek out their hosts, so they employ a wide variety of lures to bring those hosts to them. Meet Lampsilis fasciola, commonly known as a "pocketbook mussel". The glochidia of this species develop inside their mother for approximately one year, and then the mother mussel moves them to the outside of her shell into a pouch on her mantle. Here’s where it gets interesting. The mantle looks remarkably like a small fish, complete with eyespots, and the movement of the mantle looks like a small fish swimming – just the right meal for a larger fish passing by. When a hungry fish bites the mantle, the glochidia-filled pouch ruptures and the larvae emerge, latching onto the inside of the fish’s gills with adhesive threads and teeth on their shells’ valves. Once in their host, the glochidia encyst and develop into juvenile mussels and then drop down to the riverbed to mature, mate, and get ready to lure the next generation of host fish.

Contributed by Kate Bowell.


  1. Here's a video: http://www.youtube.com/watch?v=w04wvaXtTdI

  2. Very cool site, and it's nice to see a freshwater mussel included. One correction: the larvae are brooded in the females gills right up until they are released. There is no external pouch in the mantle - it is just a lure to attract a suitable host. Lampsilis faciola exhibits a lot of phenotypic variation in lure color an morphology as well, even at the population level.
    See: Zanatta et al.2007 Canadian Journal of Zoology, Volume 85,1169-1181.

  3. So does this mean that the eggs remain in the gills until the fish host comes along, at which point the mother mussel discharges the larvae into the gills of the fish host?