the exception of a few species, polyclads are marine animals
and mostly free-living, i.e., they are not parasitic. Most
polyclads are found in the intertidal zone, on the crest of
coral reefs, on coral reef slopes, on mangrove roots, as part
of fouling communities on dock pilings, or in seagrass beds.
However, they also have been collected at Pacific Ocean seamounts
from depths of 2500m. A few species are pelagic, floating
in the open ocean or hitiching a ride attached to Sargassum
found in muddy and sandy habitats tend to be interstitial.
Many benthic forms hide under rocks, in crevices, and under
coral rubble. These species are cryptic, meaning that they
hide from light and predators. It is mostly at night when
they leave their protective environs to forage for food.
acotyelan polyclad crawling along the sea bottom.
may be seen on the reef in the open even during day light.
Their bold colors advertise either a real or perceived toxicity
to potential predators thus, protecting them (see the biology
section on Color and Mimicry).
crawling over a sponge on the reef.
are not actually parasitic, they may form intimate associations
with other invertebrates. For example, species of Apidioplana
live attached to the branches of corals, and may be a problem
for people keeping saltwater aquaria. Imogine zebra
can be found living within shells occupied by hermit crabs.
Living inside reproductive cavities of brittle stars and sea
urchins are several species of Discoplana. There
the worm may feed on the gonads and eggs of the echinoderm,
and then lays its own egg capsules containing as many as 1000
young. This is probably the closest that polyclads come to
navigate the primer, use the buttons in the right panel.
These pages are
for educational purposes only. If you use any of the information
or the images in your classes, please credit these web pages.
© MK Litvaitis, 2005
credits to Leslie Newman, Andrew Flowers, or Anne DuPont,
unnless otherwise indicated.