''Chordodes formosanus'' is a horsehair worm that has the praying mantis as its definitive

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...

. Horsehair worms are obligate parasites that pass through different hosts at various stages. These worms can grow up to 90 cm long and can be extremely dangerous for their host, especially the praying mantis.

Morphology

''Chordodes formosanus'' is morphologically similar to '' Chordodes japonensis''. Both species have the same six cuticular structures of areoles on the surface, the significantly longer filaments on the female crowned areoles. Female horsehair appears to have a round and slightly swollen posterior end of their body, while males have a narrowed end.

Life cycle

# ''Chordates formosanus'' starts as a larva in the gut of the small insects that the mantis preys on. # Once the mantis ingests the infected insect, the ''C. formosanus'' starts to grow. # When it is mature, the worm secretes proteins that take over the host's nervous system, which directs the mantis to a body of water and causes it to jump in so that the worm can be excreted, at which point it breaks free to reproduce leaving a half empty mantis husk.

Host specificity

The definitive host range of horsehair worms is limited to one or few species. Because

nematomorph Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms, hairsnakes, or Gordian worms) are a phylum of parasitoid animals superficially similar to nematode worms in morphology, hence the name. Most species range in size ...

s are sometimes found after they have emerged from their host, definitive information on hosts is unknown in some species.

Geographic range

This horsehair worm parasite is prominent in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, Nepal and Taiwan. Reproductively, they are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, with the internal fertilization of eggs that are then laid in gelatinous strings. Adults have cylindrical

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

s, opening into the

cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...

. The larvae have rings of cuticular hooks and terminal stylets that are believed to be used to enter the hosts. Once inside the host, the larvae live inside the

haemocoel The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...

and absorb nutrients directly through their skin. Development into the adult form takes weeks or months, and the larva moults several times as it grows in size.

References

{{Taxonbar, from=Q21262300 Nematomorpha