Hammerhead worm - Orchid Board

Kevin_PR · #1 10-30-2013, 03:05 AM

I found what is called a hammerhead worm, Bipalium kewense, on my chids as I was checking them for snails after an late evening shower. I read that they are actually a predatory planarian. They are said to eat earthworms, snails, slugs, and insect larvae. I found 4 individuals all less than 2" long. All were found on my mounted orchids, so there are no earthworms to eat. I am hopefully assuming that they are eating my snails. I tried to confirm this but failed. I put a snail in the path of one of these bad looking guys, the snail freaked out and let go, falling to the ground and taking the predatory worm with it. I also observed a different individual scoop up a small, pinhead sized baby snail. It passed the snail down to the mid of its body where the mouth is but I disturbed them and it went on its way. Can anyone confirm that this species eats snails? They are really interesting to watch as they quickly glide over surfaces. They are not native to this island but I read they are not harmful to native species.

vjo · #2 10-30-2013, 07:09 AM

Just trying to figure out what a 'freaked out' snail looks like! Lol

katrina · #3 10-30-2013, 07:14 AM

I've read they are not something you want around. They are becoming a problem in the Southern US (not native but accidentally bought in) and are moving North. Not too long ago they started showing up in Ohio so I've read a few things on them. First...and the worst...they will decimate the earthworm population. They are not a good thing to find in your garden around here. Everything I've read discusses getting rid of them rather than allowing them to remain alive. Their first food...earthworms. I haven't read anything about them eating snails or slugs. ?? Even if they do...once they have eaten those little buggers...they will drop and go into the ground...reproduce...and eventually become a problem for P.R. Not good. Kill the b*****ds!

Aside from the earthworm killing status...they leave slime trails so, personally, I wouldn't want that near my orchids.

Kevin_PR · #4 10-30-2013, 12:11 PM

Quote:

Originally Posted by vjo

Just trying to figure out what a 'freaked out' snail looks like! Lol

Basically the snail starts thrashing its shell from side to side and twists the shell too, in a snail like manner of course. The snail was much larger than the worm, but the worm had crawled onto the snails flesh before the snail had time to withdraw. Also these snails have no operculum so they can't shut out the worms. I wonder if they have natural predators that are no longer present, to provoke such a reaction.

---------- Post added at 11:11 AM ---------- Previous post was at 11:06 AM ----------

Quote:

Originally Posted by katrina

I've read they are not something you want around. They are becoming a problem in the Southern US (not native but accidentally bought in) and are moving North. Not too long ago they started showing up in Ohio so I've read a few things on them. First...and the worst...they will decimate the earthworm population. They are not a good thing to find in your garden around here. Everything I've read discusses getting rid of them rather than allowing them to remain alive. Their first food...earthworms. I haven't read anything about them eating snails or slugs. ?? Even if they do...once they have eaten those little buggers...they will drop and go into the ground...reproduce...and eventually become a problem for P.R. Not good. Kill the b*****ds!

Aside from the earthworm killing status...they leave slime trails so, personally, I wouldn't want that near my orchids.

Wow I did not know they can wipe out earthworm populations. I had 4 individuals in a 5' area so I may have experienced a population explosion from all the snails that are around. They were all the same size too. I will round them up if I see them again. Hopefully they stay in check, they are also cannibalistic.

DavidCampen · #5 10-30-2013, 02:35 PM

Earthworms are not native to the northern forests of North America and can be considered to be invasive and harmful in these settings.
Earthworms Harming Northern Forests | LiveScience

Paul · #6 10-30-2013, 03:16 PM

In any event, quite interesting. My first thought when I saw your photos was that it looked like some sort of planaria.

AnonYMouse · #7 10-30-2013, 03:20 PM

Eeeeeeeeewwwwww, creepy!

Kevin_PR · #8 10-30-2013, 04:35 PM

Quote:

Originally Posted by DavidCampen

Earthworms are not native to the northern forests of North America and can be considered to be invasive and harmful in these settings.
Earthworms Harming Northern Forests | LiveScience

Very eye opening. I never knew that. I have seen earthworms all my life and had assumed they were native.

---------- Post added at 03:35 PM ---------- Previous post was at 03:34 PM ----------

Quote:

Originally Posted by Paul

In any event, quite interesting. My first thought when I saw your photos was that it looked like some sort of planaria.

They are a predatory terrestrial planaria. Hammerhead worm is the common name

Orchid Whisperer · #9 10-30-2013, 05:57 PM

I've never heard of these before, but will kill any I see. Earthworms are too important to the soil environment.

Bloomin_Aussie · #10 10-30-2013, 06:43 PM

I know these as ribbon worms. Not sure what they eat but you generally find them under rocks or damp places around rhe garden. The worst thing about them is the stinky slime they secrete... doesn't wash off very easily.