Nematomorpha - Dr. Bondrup

NEMATOMORPHA Sarah Berube Naomi Demers-Agterberg Mike Downing

Miranda Downing

GORDIOIDEA AND THE GORDIAN KNOT • In Greek mythology, King Gordius, fastened his wagon to his horse's yoke with a knot that was impossible to untie. • An oracle announced that whoever released the knot would be the next ruler of Asia. • Alexander the Great cut the Gordian knot with his sword, and went on to conquer Asia.

PLACE IN HISTORY • Nematomorpha (from the Greek nema, "thread," and morphe, "shape")

• The first known fossil record of Nematomorpha dates from the Eocene (40 - 70 million years ago)

CLASSIFICATION • Domain: Eukarya • Kingdom: Animalia • Phylum: Nematomorpha • Classes: Gordoida and Nectonematoidea • Species: 240

GORDIOIDEA AND NECTONEMATOIDEA • Gordioidea live in freshwater(>200 species) • Nectonematoidea live in saltwater, and do not use terrestrial hosts (5 known species)

• Both genera prefer shallow water, and nectonematoidea stay in coastal areas. • While Gordioidea is scattered across the globe, nectonematoidea has only been found in restricted areas of the United States, Europe and the Bay of Fundy.

MORPHOLOGICAL FEATURES • No excretory pores or lateral chords.

• Nervous system made up of dorsal ganglion and ventral chord. • Gonads open into posterior cloaca with intestine. Larval Hairworm

• Intestine is somewhat degenerate

EVOLUTION • Hairworms are related to roundworms, thorny-headed worms, kinorhynchs, and rotifers • Originally classified as the descendants of scalidophorans – a group that includes several related parasitic phyla

• Spread to different ecosystems with their hosts. • The classification of hairworms is changing because of a new phylum, under which nematomorpha would be a class, and gordioidea and nectonematoidea would be subclasses.

LIFE CYCLE

EGGS AND LARVAE • Female Nematomorpha can lay up to 10 million eggs in their lifetime • Eggs are fertilized internally and then laid along aquatic plants in a long string of millions of eggs • Once fertilized, the eggs mature into larvae after 2-4 weeks

AN UNWANTED PASSENGER • Hairworm larvae are often consumed by bottom feeders • The larvae, once ingested by this host, “encyst” themselves in a protective barrier • Once encysted, the hairworm can survive for up to a year in their protective barrier • Encysted larvae wait until they can get to terrestrial hosts • Larvae require a terrestrial host for further development

FINDING THE RIGHT HOST • If the paratenic host dies or is eaten the larvae either encysts in the new host or de-cysts and tries to get eaten again • The most common form of transfer from water to land is through aquatic insects • insects ingest the hairworm in their own larval form before metamorphosis, when they gain wings and leave the water

SAFE HOUSE • Once inside the cricket, larvae de-cyst, penetrating through the stomach and into the body cavity, and begin absorbing nutrients through their skin

• The only energy used by Nematomorpha while inside the cricket is for development - no other function is completed here • All other functions are performed outside their hosts, allowing them to develop almost fully before leaving

KAMIKAZE WORMS • In later stages of development, the juvenile releases chemicals into the system of the host which alters brain functions • Once these chemicals are released the hosts behave erratically, moving into unusual environments and occasionally jumping into water • Once the developed hairworm senses liquids surrounding the host it then exits, returning to its natural habitat to live as an free-moving life form

• The growth period only takes between 4-20 weeks in total

THE END

SOURCES •

Bolek, M. ,. E. A. (2011, August). Hairworm biodiversity survey. Retrieved from http://www.nematomorpha.net/Nematomorphs.html

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Films, V. B. (2002). Hairworm leaving a cricket. Retrieved from http://www.nature.com/nature/journal/v440/n7085/extref/440756a-s2.mov

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Hanlet, B. (2002, June 1). Morphometric analysis of nonadult characters of common species of american gordiids (nematomorpha: gordioidea). Retrieved from http://digitalcommons.unl.edu/cgi/

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Long, B. (2007, April 25). Nematomorpha. Retrieved from http://www.drbilllong.com/AnPhyla/NematomorphaII.html

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Shapiro, L. (2008). Nematomorpha. Retrieved from http://eolspecies.lifedesks.org/pages/30214