22 June 2009

Bipalium adventitium — Part 1

And now for something completely different: the land planarian Bipalium adventitium.

BipaliumAdventitium1

I found this critter a few weeks ago in the park near my house. As usual, I was looking for slugs and snails and there was this planarian crawling around the roots of a tree.

BipaliumAdventitium2
The fully stretched animal—they have very flexible bodies—was ~8 cm long.

Although Libbie Hyman described this species using the specimens collected in Pasadena, California (Hyman, 1943; pdf), it is believed to have been introduced to North America originally somewhere from eastern Asia. Here are the 3 exotic Bipalium species found in the U.S.


From Ducey et al. 2007. Southeastern Naturalist 6:449.

Bipalium adventitium preys on earthworms. Mine ate one earthworm I had put in its container, but I wasn't around to take its pictures during the process. Subsequently, it produced 3 egg cocoons. If it were a native species, I would have released it back into the wild. But, and despite the fact that it is more or less a naturalized alien, I decided that the best thing to do was to preserve it in alcohol for posterity.

Continues in Part 2.

17 comments:

budak said...

are earthworms native or invasive in your parts (geographically, not bodily)? Maybe the flatworms are thriving by feeding on the alien annelids?

AYDIN ÖRSTAN said...

I was wondering about that too, but I don't know the answer. I have to do a search.

Megan said...

Geez, that planarian's large. And yet, I've never seen one in Maryland.

gillesarbour said...

Why do I find this planarium repulsive? It rarely happens, I usually see beauty in all beings. Something looks parasitic - maybe the head. Or is it simply fear of the unknown - I have never seen anything like this. I am only familiar with the small planarium we find in water.

xoggoth said...

8cm! good grief. We only have tiny things (up to about 12mm) in ponds although they are rather efficient carnivores, devouring much bigger and more active animals.

The warnings we had a few years back about an imported New Zealand Flatworm spreading throughout the UK from the south and destroying all our earthworms have proved unfounded - so far.

Raag said...

What is the size of these worms?

-- Raag

AYDIN ÖRSTAN said...

Fully stretched ~8 cm long, but only ~2 mm wide.

terrific said...

I live in Southeast Georgia and we have found two of these creatures in the last few weeks. One outside on my door and now tonight one in our shower. Yuk! My daughter got scared and sprayed it with Tilex unfortunately, killing it. So now I have it in a mason jar until I could find out more. Now I guess I have my answer. Do they only prey on earthworms and are they harmless?

terrific said...

We have found two now in Southeast Georgia. My daughter killed the 2nd one with Tilex in the shower. Are they harmless?

AYDIN ÖRSTAN said...

They are harmless to humans.

Anonymous said...

UGH! I found this worm on my cats neck. Does anyone know if it is harmful to cats?

kim said...

Are these harmful to cats or dogs?
I found one on my cat this morning and freaked out! I can't seem to find anything on the internet to answer this question.

AYDIN ÖRSTAN said...

If what you found on your cat is indeed a Bipalium, it shouldn't harm your cat. But what your cat has may be a tapeworm, an internal parasite & a distant relative of Bipalium. I recommend that you take a stool sample of your cat to the vet.

Colin Purrington said...

Thanks for posting that key.

Anonymous said...

thanks for the info... I live in Paradise,Califorina and just recently I have found five of these worms and I freaked out cus I thought it was a tapeworm, I did take it to my local vet cus I have a dog and children and I did not want them to get it and no one knew what this insect so, I researched it myself and found your sight.... My question is how do you get rid of them......Thank you concerned Mother Of Two!!!!!

AYDIN ÖRSTAN said...

Land planarians are not parasitic. They won't harm people or dogs.
They are cryptic animals, so it would be very difficult to eliminate them. And you don't want apply pesticides all over your garden, because that would end up being more harmful to your children & dog.

rustypup49 said...

Vancouver, Washington - Just found what I think was an Adventitium in my garden. (I say "was" because I dunked it in alcohol.) I'll bet it came with the nursery plants I buy at Home Depot, etc. The head was more straight up & down (not uniformly wedge-shaped) altho the head kept morphing like a tapeworm. I didn't like the look of it; I think because an earthworm looks healthy & pinkish & translucent. This thing looked like a slug-worm and therefore ooky LOL. Now that I know they eat earthworms in my garden, I don't feel guilty about the alcohol bath.

@kim & Anonymous: A tapeworm's color is usually dead white or offwhite in color, like overcooked spaghetti. Their entire body can morph or change shape from a blob to elongated = ewww! I have cats and I can empathize with your concern.