> various animal groups
learn only 3 things about them ...
of tiny worms may look like roots, don't step on them.
Some can bite or sting. Don't touch!
live deep in the sand, don't dig them out.
seen? Tubeworms are common on all our shores and near mangroves.
They are most obvious on sand bars and flat shores (sandy or muddy)
where they stick out of the surface in large numbers. In seagrass
areas, some are found in large numbers in mounds that can be 1m or
more wide. Their tubes can extend quite deep into the ground, only
a little bit of the tube sticks out of the ground. At low tide, the
worm may be even deeper still. Some tubeworms can give a nasty bite.
Please don't dig up tubes to try to see the worm.
What are tubeworms? There are many kinds of worms
on our shores. Worms that create tubes and live inside them are called
tubeworms. But these are not necessarily closely related to one another.
And not all animals that live in tubes are worms (see below).
Most tubeworms are segmented bristleworms
(Phylum Annelida, Class Polychaeta). Some of these bristleworms have
little hooks on their sides to help them move up and down their tubes.
Others have reduced or no bristles. They are often beautifully iridescent.
Some have tentacles on their heads to filter feed at high tide or
to sweep the surroundings for edible titbits. Others have powerful
jaws that can give a nasty bite. They are ferocious predators that
seize passing prey while most of their bodies remain safely inside
Tubes are so cosy that other creatures may move in with the worm!
Such creatures include tiny crabs, clams and other worms.
of worm snot! Some tubes are thin and delicate and look
more like roots of plants, others are translucent that look like drinking
straws, while some are as thick as rubber tubing. The tube diameter
ranges from 0.2-1cm. Part of the tube from 1-10cm may stick out of
the surface, although the entire tube that is buried is usually a
lot longer. Most tubes found in the ground are made with mucus. To
strengthen their tubes, some worms mix in sand, bits of shells or
other debris. Some worms such as keelworms
build tubes made of calcium carbonate on hard surfaces. The Giant
reef worm (Eunice aphroditois) builds a paper tube in crevices
in coral rubble or even living coral.
Some like the Solitary tubeworm
(Diopatra sp.) may incorporate a leaf at the top of the tube.
This may help to reduce water loss or transmit the vibrations of nearby
predators or prey.
Some tubeworms live close together in large numbers. The hundreds
of tubes of the tiny Gregarious
tubeworm may form furry carpets that cover several metres of sand.
Fanworms and keelworms
are other kinds of worms that live in tubes too.
Sometimes confused with other
animals that build tubes to live in but which are NOT worms. These
anemones and vermetid
snails. More on how to tell
apart hard tubes made by worms from those made by other animals.
Why live in a tube? A tube provides
some protection from the abrasive sand, as well as most predators.
It is also a lair from which predatory worms can hide to catch passing
prey. Tubes may go quite deep to where it remains moist and cool at
low tide. Tubes that project some distance above the bottom may allow
the worms to reach clean, oxygenated water above a muddy or sandy
bottom. Building a tube on a hard surface also allows worms to live
in places where they cannot burrow (see keelworms).
Tubeworm babies: Most tubeworms
have separate genders. In some, eggs and sperm are released into the
water simultaneously where they are fertilised. In others, eggs are
retained or brooded within their tubes. Some eggs develop into free-swimming
larvae that drift with the plankton before settling down and developing
into new tubeworms.
Role in the ecosystem: Tubeworms are eaten by
many animals higher up in the food chain. Many kinds of shorebirds,
for example, feed on worms, including tubeworms, for sustenance to
make their long migratory journeys.
The tubes of Gregarious tubeworms
may also help anchor sediments. These tubeworms may live packed so
closely together that they form mounds up to 1m or more across! These
mounds trap pools of water at low tide for small creatures to shelter
in. Thesetubeworms are often seen in areas with seagrass. Perhaps
these worms anchor the sediments that allow seagrasses to grow, or
Human uses: Fishermen sometimes
dig out tubeworms to use as bait.
Status and threats: Like other
creatures of the intertidal zone, they are affected by human activities
such as reclamation and pollution. Trampling by careless visitors
and over-collection as bait can also have an impact on local populations.
Other tube-makers: Not all animals
that live in tubes are correctly called worms. Some other animals
that build and live in tubes include: peacock
anemones (Order Ceriantharia, Phylum Cnidaria) that build soft
leathery tubes; vermetid
snails (Family Vermetidae, Class Gastropoda, Phylum Mollusca)
that build hard chalky tubes.
Various kinds of tubes made by worms.
Chek Jawa, Feb 02
a shaggy rug among
more dispersed Straw tubeworms.
Chek Jawa, Dec 07
Changi, Aug 05
out to grab a mangrove propagule.
Pasir Ris Park, Apr 10
more complex looking!
Changi, Apr 12
tubeworms on Singapore shores
on Singapore shores
Worms that build tubes may belong to a wide range of groups. These
Class Polychaeta (bristleworms)
commonly seen awaiting identification
With grateful thanks to Leslie H. Harris of the Natural
History Museum of Los Angeles County for comments on and identifying
some of these tubeworms.
- Ng, P. K.
L. & Y. C. Wee, 1994. The
Singapore Red Data Book: Threatened Plants and Animals of Singapore.
The Nature Society (Singapore), Singapore. 343 pp.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.
- Jones, R.E.
(Ed.) et al. 2000. Polychaetes and Allies: The Southern Synthesis
Australian Biological Resources Study, Canberra. 465pp.