Worm Wars in the Intertidal - Observation of the Week, 9/14/21

Our Observation of the Week is this worm-on-worm action - a New Zealand Paddle Worm (Eulalia microphylla) attacking a Flatworm (Phylum Platyhelminthes)! Seen by @dave_holland.

Last month, Dave Holland explored the intertidal area in West Auckland with Oscar (“another ‘nature addict’”), who he’d recently met. “He was showing me all the super cool spots around his home base,” says Dave.

This particular day we ended up flipping rocks in the intertidal zone - a great way to find all sorts of unusual critters. Normally any critters living on the underside of the rock exit stage left as fast as possible, but this time something very very interesting happened.

As he was recording video of a flatworm on the rock, Dave saw New Zealand paddle worm came across it and “the light green stuff exploded out and grabbed the flatworm then would shrink back into the [paddle worm] if the flatworm wriggled out!” Forgetting that he was shooting video, Dave started snapping photos with his camera instead, and those are what you see in this blog post. 

A member of Family Phyllodocidae, the paddle worm is a polychaete, also known as bristle worms due to the chitinous bristles (called chaetae) protruding from each segment. A polychaete can evert its pharnyx, or in some cases a longer proboscis, for hunting and feeding, and this one’s nice and bright green!  

While a fan of all nature, Dave (below, in Australia) says his current interests lie with New Zealand’s over 100 native reptile species, accurately identifying Vespula germanica and Vespula vulgaris (both invasive to the islands), and finding newly naturalizing exotic plant species. 

New Zealand already has literally the worst weed problem on Earth with over two and a half thousand species of exotic plant [having] escaped cultivation and invading/diluting/replacing our native ecosystems. Myself and other iNatters are discovering new plant species escaping every day, some of these are the new generation of climax weeds that will invade, overtop and replace the huge areas of newly created habitat of urban native plantings that are being created around cities as the ecological consciousness of the urban population improves.

He also recently started the Bird Dispersed Weed & Potential Weeds NZ project to bring awareness to non-native plants being dispersed by birds.

While acknowledging that it’s “far from perfect,” Dave thinks iNat “has the power to educate, education has the power to change consciousness, changing consciousness has the power to change the future.” And also, “using iNat has further decreased my speed [when out in nature]. I was pretty damn slow before because I have always seen cool stuff, but using iNat has made my progress through the world gastropodially slow, because now I am looking at nature through a macro lens.”

(Photo of Dave by Kaddi Bitcher)

- Take a look at some of the remarkable most-faved polychaetes and flatworms on iNat.

- This video of Los Angeles County marine worms has some nice footage of a polychaete everting its pharyx at around 2:10.

- Check out two past wormy Observations of the Week - this enormous polychaete and this land planarian!

Posted on September 14, 2021 11:05 PM by tiwane tiwane


Great sequence! For a polychaete falling victim to a Purple Ribbon Worm's proboscis see my observation at https://www.inaturalist.org/observations/33435868

Posted by ewrunn1ng about 2 years ago

This is so cool!! Thanks for sharing it!

Posted by ocean_beach_goth about 2 years ago

iNat has made my progress through the world gastropodially slow - ha, I love this one!!! (which often applies to my pace as well these days...)

Posted by jakob about 2 years ago

They are so fascinating and always staying glossy. I just love them.

Posted by aviewer about 2 years ago

"iNat has made my progress through the world gastropodially slow" I love that one! Same here!

Posted by amarzee about 2 years ago

Thx all :) @ewrunn1ng those are cool pics of urs!

Posted by dave_holland about 2 years ago

@dave_holland -- Thanks. I was staring at the boulder on which that "worm war" was occurring for so long, other people on the beach came over to see what was wrong with me!

Posted by ewrunn1ng about 2 years ago

"what was wrong with you" you and me we live in the same world, people are always wondering what is wrong with me! Bum up face in the dirt looking at some fascinating new bug 🤣

Posted by dave_holland about 2 years ago

@oscar_dove woot woot!

Posted by dave_holland about 2 years ago

@dave_holland ah yes, i remember this! Always something crazy to be found in the intertidal

Posted by oscar_dove almost 2 years ago

@dave_holland - such a cool observation! I also move around outside 'gastropodially slow' - and it makes me so happy to know I'm not the only one examining unusual things under rocks :D

Posted by lisa_bennett almost 2 years ago

😂 yes

Posted by dave_holland almost 2 years ago

Add a Comment

Sign In or Sign Up to add comments