forces acting on it, or by advecting virtual particles in ocean and atmospheric circulation models. earlier studies modelled the movement of the man o' war with lagrangian particle tracking to explain major beaching events. in 2017, ferrer and pastor were able to estimate the region of origin of a significant beaching event on the basque coast. they ran a lagrangian model backwards in time, using wind velocity and a wind drag coefficient as drivers of the man o' war motion. they found that the region of origin was the north atlantic subtropical gyre. in 2015 prieto et al. included both the effect of the surface currents and wind to predict the initial colony position prior to major beaching events in the mediterranean. this model assumed the man o' war was advected by the surface currents, with the effect of the wind being added with a much higher wind drag coefficient of 10 percent. similarly, in 2020 headlam et al. used beaching and offshore observations to identify a region of origin, using the joint effects of surface currents and wind drag, for the largest mass man o' war beaching on the irish coastline in over 150 years. these earlier studies used numerical models in combination with simple assumptions to calculate the drift of this species, excluding complex drifting dynamics. in 2021, lee et al. provide a parameterisation for lagrangian modelling of the bluebottle by considering the similarities between the bluebottle and a sailboat. this allowed them to compute the hydrodynamic and aerodynamic forces acting on the bluebottle and use an equilibrium condition to create a generalised model for calculating the drifting speed and course of the bluebottle under any wind and ocean current conditions. ecology predators and prey blue dragon, glaucus atlanticus violet snail, janthina janthina the portuguese man o' war is a carnivore. using its venomous tentacles, a man o' war traps and paralyzes its prey while "reeling" it inwards to the digestive polyps. it typically feeds on small adult fish and fish fry (young fish), and sometimes zooplankton, shrimp and other small crustaceans. man-of-war fish the organism has few predators of its own; one example is the loggerhead turtle, which feeds on the portuguese man o' war as a common part of its diet. the turtle's skin, including that of its tongue and throat, is too thick for the stings to penetrate. also, the blue sea slug glaucus atlanticus specializes in feeding on the portuguese man o' war, as does the violet snail janthina janthina. the ocean sunfish's diet, once thought to consist mainly of jellyfish, has been found to include many species, the portuguese man o' war being one such example. the blanket octopus is immune to the venom of the portuguese man o' war; young individuals have been observed to carry broken man o' war tentacles, which males and immature females rip off and use for offensive and defensive purposes. external video how portuguese man o' war stings and eats prey – blue planet ii the man-of-war fish, nomeus gronovii, is a driftfish native to the atlantic, pacific and indian oceans. it is notable for its ability to live within the deadly tentacles of the portuguese man o' war, upon whose tentacles and gonads it feeds. rather than using mucus to prevent nematocysts from firing, as is seen in some of the clownfish sheltering among sea anemones, the fish appears to use highly agile swimming to physically avoid tentacles. the fish has a very high number of vertebrae (41), which may add to its agility and primarily uses its pectoral fins for swimming—a feature of fish that specialize in maneuvering tight spaces. it also has a complex skin design and at least one antibody to the man o' war's toxins. although the fish seems to be 10 times more resistant to the toxin than other fish, it can be stung by the dactylozooides (large tentacles), which it actively avoids. the smaller gonozooids do not seem to sting the fish and the fish is reported to frequently "nibble" on these tentacles. commensalism and symbiosis the portuguese man o' war is often found with a variety of other marine fish, including yellow jack. these fish benefit from the shelter from predators provided by the stinging tentacles, and for the portuguese man o' war, the presence of these species may attract other fish to eat. life cycle lifecycle of the portuguese man o' war. the mature physalia physalis is pictured floating on the ocean surface, while early development is thought to occur at an unknown depth below the ocean surface. the gonodendra are thought to be released from the colony when mature. the egg and planula larva stage have not been observed. man o' war individuals are dioecious, meaning each colony is either male or female. gonophores producing either sperm or eggs (depending on the sex of the colony) sit on a tree-like structure called a gonodendron, which is believed to drop off from the colony during reproduction. mating takes place primarily in the autumn, when eggs and sperm are shed from gonophores into the water. as neither fertilization nor early development have been directly observed in the wild, it is not yet known at what depth they occur. a fertilized man o' war egg develops into a larva that buds off new zooids as it grows, gradually forming a new colony. this development initially occurs under the water, and has been reconstructed by comparing different stages of larvae collected at sea. the first two structures to emerge are the pneumatophore (sail) and a single, early feeding zooid called a protozooid; later, gastrozooids and tentacle-bearing zooids are added. eventually, the growing pneumatophore becomes buoyant enough to carry the immature colony on the surface of the water. venom man o' war beached in brazil the stinging, venom-filled nematocysts in the tentacles of the portuguese man o' war can paralyze small fish and other prey. detached tentacles and dead specimens (including those that wash up on shore) can sting just as painfully as those of the live organism in the water and may remain potent for hours or even days after the death of the organism or the detachment of the tentacle. stings usually cause severe pain to humans, leaving whip-like red welts on the skin that normally last two or three days after the initial sting. the pain normally subsides after about one to three hours (depending on the victim's biology). however, the venom can travel to the lymph nodes and may cause symptoms that mimic an allergic reaction, including swelling of the larynx, airway blockage, cardiac distress and an inability to breathe. other symptoms may include fever and shock and, in some extreme cases, even death, although this is extremely rare. medical attention for those exposed to large numbers of tentacles may become necessary to relieve pain or open airways if the pain becomes excruciating or lasts for more than three hours, or if breathing becomes difficult. instances in which the stings completely surround the trunk of a young child are among those that may be fatal. the species is responsible for up to 10,000 human stings in australia each summer, particularly on the east coast, with some others occurring off the coast of south australia and western australia. treatment of stings stings from a portuguese man o' war can result in severe dermatitis characterized by long, thin, open wounds that resemble those caused by a whip. these are not caused by any impact or cutting action, but by irritating urticariogenic substances in the tentacles. in 2017, vinegar (acetic acid, 5% acidity) rinsing (irreversibly inhibiting cnidae discharge), then applying heat, water or hot pack, at 45 °c (113 °f), for 45 minutes, was found to be the most effective treatment, while rinsing with seawater, cold packs, urine, baking soda, shaving cream, soap, lemon juice, alcohol, rubbing alcohol, and cola will trigger the release of more venom. in 2009, isolated studies had suggested that in some individuals vinegar dousing may increase toxin delivery and worsen symptoms. in 1988, vinegar was claimed to provoke hemorrhaging when used on the less severe stings of cnidocytes of smaller species. gallery man o' war warning sign, hawaii portuguese man o' war, miami beach, florida, march 2008 portuguese man o' war, palm beach, florida, may 2013