The Bad and the Ugly - predators, disease, & competitors 

eroded.jpg (28036 bytes) eroded-2.jpg (46161 bytes) A severely eroded but still living specimen of Quadrula from the Black River in eastern Missouri.  Causes of this condition are not understood.  Both chemical and biological factors may be involved.
protists.jpg (24769 bytes) Unidentified ciliate protists attacking a juvenile Lampsilis.  One of the unicells (arrow) is forcing its way between the partly open valves of the mussel.  These protists can also invade the marsupia and feed on glochidia.  However, it is not yet clear whether they attack healthy juveniles or merely act as scavengers on dead or dying individuals.  
worm&juvee.JPG (13291 bytes) This rhabdocoel turbellarian flatworm (Microstomum sp.) has ingested a juvenile Lampsilis, the shell of which is visible through the worm's body wall.  At least two species of rhabdocoels prey on juvenile mussels.  Rhabdocoels also prey on juvenile Corbicula (Sickel 1998).
zebra1.jpg (33959 bytes) Zebra mussels encrusting the posterior end of a fatmucket (Lampsilis siliquoidea).  These non-native bivalves devastate native mussels by attaching to them, interfering with their feeding and by competing directly for food. (Specimen from Lake Michigan).

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