Being stung by a bluebottle (Physalia utriculus), also known as the Pacific man o’ war, is a rite of passage for kids who spend big chunks of their summer holidays on beaches on the east coast of Australia. A bluebottle sting is always a painful experience – sometimes excruciatingly so – but it’s rarely life-threatening, except for the extremely small percentage of people who are allergic to bluebottle venom and may suffer an anaphylactic reaction if stung.
As many as 30,000 stings are reported each year along the east coast of Australia … especially when the winds are blowing from the North East. The bluebottle float has aerodynamic properties and it seems likely that sailing characteristics may be modified by muscular contraction of the crest. The direction of their drift is not determined by wind alone. The downwind course is determined by the curvature of the float and the underwater resistance of the rest of the colony.
Some bluebottles are "left-sided” and others are "right-sided”. A left-sided bluebottle drifts rightward from the direction the wind blows, whereas a right-sided one drifts leftward. This results in a more even distribution of these animals throughout the oceans. Nature doing that nature thing.
So what else is interesting?
The bluebottle is not actually a single animal but rather a colony of four kinds of highly modified individuals (zooids). The zooids are dependent on one another for survival.
One of these is the bluebottle’s float – the pneumatophore. This is usually no wider than 10cm and is like a floating blue plastic bag that creates its own air-like gas with which it fills itself. Then there are the dactyloids, which form the tentacles that trail out for up to 3m and are covered in numerous tiny stinging cells called nematocysts. Their role is to detect and catch prey, which are then transferred to the gastrozoids, which handle digestion. The fourth group of zoids – the gonozoids – are involved with the asexual reproduction of the hermaphroditic bluebottle.
The bluebottle, distinguished by a smaller float and a single long fishing tentacle, is a regional variation of the significantly-more-venomous Portuguese man o' war. The name comes from a resemblance of the animal to a Portuguese square-rigged sailing warship from the 15th century called a “caravel” … and also its reliance on the wind for its movement.
This nautical theme is even extended to the collective noun of bluebottles … a flotilla of bluebottles.
Finally, and just so you know, if you ever get stung by a bluebottle, the most effective treatment is the application of heat, hot water or a hot pack at 45ºC for 45 minutes. Rinsing with sea water, cold packs, urine(!), baking soda, shaving cream, soap, lemon juice, alcohol or cola will just trigger the release of more venom.
Steer clear!
Story Idea: Remo Giuffré
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References
https://en.wikipedia.org/wiki/Portuguese_man_o%27_war
https://australian.museum/learn/animals/jellyfish/bluebottle/
https://www.australiangeographic.com.au/fact-file/bluebottle/
https://www.tidaltao.com/blog/107-blog-news/218-5-things-you-probably-didn-t-know-about-bluebottles
https://theconversation.com/the-blue-bottles-are-coming-but-what-exactly-are-these-creatures-48675
Images
1. Bluebottle. Photograph: Stephen Frink
2. Bluebottles at Lennox Head. Photo Credit: Surfit Lennox
3. Man o' war signage in Hawaii
4. Anatomy of a Physalia physalis colony including the function of each zooid
5. Portuguese square-rigged caravel, 1502
6. Bluebottle stings. Image: jonessweethomes.com
