Portuguese Man-of-War

Morphology

The Portuguese man-of-war is a colorful organism that is closely related to the jelly fish but is actually colony of polyps, or individuals. These colonies may consist of a few individuals to up to many as 1000 individuals. Each of these polyps are specialized, there are four different polyps consisting of pneumatophores, doctylozooids, gastrozooids, and gonozooids. These different specialized polyps each have specific functions. Pneumatophore is a gas filled sac which used for movement, such as to float. They do not posses swimming structures, because of this they depend on the ocean current and wind to drift. Doctylozooid polyps create the tentacles which are used to catch prey or for protection. These tentacles on average grow to be about 30 feet but may extend up to 100 feet.These long, contractile tentacles contain many sphere-like stinging cells of both small and large sizes known as cnidocytes or nematocysts, this is used to paralyze the prey as well as for protection. Gastrozooid polyps are used for feeding and digestion. They have a carnivorous diet that consists of small crustaceans and larval fish about 4 to 10 centimeters long. Gonozooid polyps create the gonads and are used for reproduction.

Toxin

The nematocysts secrete a powerful toxin that can be very harmful to other organisms. This toxin is so potent that even when the nematocyst is dehydrated, the nematocyst still retains its stinging ability. The toxicity of the nematocyst is lost when it is exposed to extreme heat or treated with an organic solvent. While low temperatures allow the toxicity to last even longer. A single sting can cause severe pain, skin lacerations, convulsions, and difficulty breathing. In some cases, the sting may even cause death.

Distribution

The Portuguese man-of-war is typically found floating atop warm, marine water. They are found in subtropical climates such as the Indian Ocean, the Atlantic Ocean, and the Pacific Ocean. They prefer the deep waters but there is also a great abundance found along the coasts of Britain and Ireland, as shown in the image to the right. More recently, there has been an outbreak of the Portuguese man-of-war along the coasts of Brazil.

Fun Facts!

•There are only two animals that are unaffected by the toxins of the Portuguese man-of-war, the loggerhead turtle and the Nomeus gronovii, a small fish.

•Some theories suggest, Portuguese man-of-war received its name because of the resemblance to an 18th century Portuguese warship. Other theories suggest it was because they resembled the shape of the helmets worn by Portuguese soldiers.

Works Cited

Lane, Charles E. “The Portuguese Man-of-War.” Scientific American, vol. 202, no. 3, 1960, pp. 158–171., www.jstor.org/stable/24941298.

Pontin, D.R. & Cruickshank, R.H. Hydrobiologia (2012) 686: 91. https://doi-o rg.proxy.lib.iastate.edu/10.1007/s10750-011-0994-8

“Portuguese Man-of-War - Physalia Physalis - Details.” Encyclopedia of Life, eol.org/pages/1005764/details.

“Portuguese Man-o’-War.” Waikīkī Aquarium, 11 Sept. 2017, www.waikikiaquarium.org/experience/animal-guide/invertebrates/jellies/portuguese-man-o-war/.

Purcell, Jennifer E. “Predation on Fish Larvae by Physalia Physalis, the Portuguese Man of War.” Marine Ecology Progress Series, vol. 19, no. 1/2, 1984, pp. 189–191. JSTOR, JSTOR, www.jstor.org/stable/24816954.

US Department of Commerce, National Oceanic and Atmospheric Administration. “What Is a Portuguese Man o' War?” NOAA's National Ocean Service, 6 July 2015, oceanservice.noaa.gov/facts/portuguese-man-o-war.html.