title for a learn-about section in A SNAIL'S ODYSSEY
  Foods, feeding, & growth
  No studies appear to have been done specifically on growth of either flatworms or ribbon worms. Foods of both types of worms are considered here, while PREY CAPTURE BY NEMERTEANS is in its own section.
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  Foods of flatworms
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Research study 1
 

photographA small percentage of solitary tunicates Corella willmeriana in Copper Cove, British Columbia and in embayments at Bremerton, Washington are found to have predatory flatworms Eurylepta leoparda feeding within their general body cavity.  The worms preferentially eat the branchial basket then move onto the other internal organs until only an empty test is left. An adult Eurylepta enters a prey tunicate by rolling into a tube and sliding into the branchial siphon, but there is some evidence that they also enter earlier in life as Müller’s larva. Lambert 1968 Biol Bull 135: 296; Ching 1977 Can J Zool 55: 338. Photograph courtesy Ron Long, SFU, Burnaby, British Columbia.

 

 

A tunicate Corella willmeriana being consumed by at least 5
flatworms Eurylepta leoparda. One worm at the 7-o'clock position can
be distinguished by the brown "leopard" spotting on its dorsal surface 2X

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Research study 2
 

drawing of a flatoworm Notocomplana acticola catching a crustacean preyphotograph of a flatworm Notocomplana acticola crawling in a mussel bedFeeding in flatworms Notocomplana (Notoplana) acticola collected from tidepools in southern California involves first gripping the prey, such as a small crustacean, in a folded edge of the body, then conveying it to the midventral mouth for ingestion (see drawings on Right). If especially hungry, the worm may lunge at its prey, and in this way can consume 3-5 adult brine shrimps within a 5-min period.  A worm experimentally decerebrated is still able to recognise food and can ingest it using local reflexes.  A brainless Notocomplana survives only for a few days, but worms with only its major nerves surgically cut will heal to full functionality.  The authors demonstrate that the ends of these cut nerves fuse within 8h and are once again able to conduct action potentials.   If not allowed to heal, full functionality is still restored within 36-48h, suggesting that new or normally unused nervous pathways can be recruited.  Koopowitz et al. 1976 Biol Bull 150: 411.

NOTE  this is done by punching the cerebral ganglia out with a 1mm-diameter glass capillary tube

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photograph of a flatworm Kaburakia excelsa crawling in a dish in the lab, taken from a video

CLICK HERE to see a video of a flatworm Kaburakia excelsa crawling within an open dish in the laboratory. Note the branched or polyclad condition of the gut in the second part of the video after the worm has been flipped upside-down. The worm is 8cm in length.

NOTE video replays automatically

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Research study 3
 

photograph of polyclad flatworm Notocomplana litoricola courtesy Sandra Millen, UBC, Vancouver, B.C.Observations in Sonoma County, California indicate that the polyclad Notocomplana (Freemania) litoricola is a predator of limpets Lottia scutum.  Laboratoy tests show that this limpet species will either run away from contact with the flatworm (76%) or “mushroom”, that is, raise its shell and inflate the foot (20%).  In similar tests about 56% of Lottia digitalis show no response and 44% mushroom, while 100% of Lottia scabra exhibit no response.  In comparison, none of the limpets responds to contact with Notocomplana (Notoplana) acticola.  The authors note that the distributions of Freemania and Lottia scutum overlap below the mid-tide level on the shore, but L. digitalis and L. scabra live above the zone commonly frequented by FreemaniaLottia scabra also benefits from the protection offered by its home scar.  Phillips & Chiarappa 1980 J Exp Mar Biol Ecol 47: 179.  Photograph courtesy Sandra Millen, UBC, Vancouver, B.C.

 

 

Predatory flatworm Notocomplana litoricola
perhaps hunting for limpets Lottia scutum 1X.
This flatworm is also known to prey on barnacles

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  Foods of ribbon worms
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Research study 1
 

photograph of nemertean Tubulanus polymorphus with a nereid worm that is has regurgitatedFoods of nemerteans, depending upon species, include live invertebrate prey, scavenged matter, and algae. Parasitic species on crabs eat the eggs of their hosts.  Many carnivorous species actively pursue their prey and follow them into their burrows or crevices; others adopt a sit-and-wait strategy, and ambush their prey in strategic locations.  For reviews see McDermott & Roe 1985 Am Zool 25: 113; Thiel & Kruse 2001 Hydrobiologia 456: 21.

 

 

 

 

 

Nereid polychaetes are common prey items for several
species of west-coast nemerteans. Here, a Tubulanus
polymorphus
has regurgitated the remains ofa nereid
meal, accompanied by much mucus 1.5X

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Research study 2
 

table of prey species (polychaetes) eaten by the nemertean worm Paranemertes peregrinaParanemertes peregrina is a predator of polychaete worms.  Analysis of fecal bundles of Paranemertes collected in situ at 3 locations in northern Washington shows that prey selectivity largely depends upon what polychaetes are available in the habitat (see table at Left).  At Snug Harbor, for example, the bulk of the diet is made up of nereids.  In comparison, at Edmonds, spinoid and polynoid polychaetes comprise 94% of the diet, while nereids make up only 4%.  Roe 1976 Biol Bull 150:80. Photograph courtesy Jackie Soanes, Bodega Marine Laboratory, California.photograph of nemerteans Paranemertes peregrina attacking and eating a nereid polychaete, courtesy Jackie Soanes, Bodega Marine Laboratory, California

 

 








Two nemerteans Paranemertes peregrina
capturing a nereid polychaete. The nemertean
on the Left has mostly engulfed the prey 1X

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Research study 3
 

photograph of nemertean Amphiporous sp. engulfing a prey amphipod courtesy Tim Rawlings, Cape Breton University, Sidney, Nova ScotiaThe high intertidal-dwelling nemertean Pantinonemertes californiensis feeds on crustaceans, mostly semi-terrestrial amphipods Traskorchestia traskiana, and also isopods including Ligia occidentalisRoe 1993 Hydrobiologia 266: 29. Photo graph courtesy Tim Rawlings, Cape Breton University, Sidney, Nova Scotia.

 

 

 

 

 

 

 

Nemertean Amphiporous sp., also a
high-intertidal dweller, engulfs an
amphipod crustacean. The amphipod
can be seen at the lower end of the
worm within the pharynx 1X

 

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