Blue-ringed octopus

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Blue-ringed octopus
Hapalochlaena lunulata2.JPG
Greater blue-ringed octopus
(Hapalochlaena lunulata)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Octopodidae
Genus: Hapalochlaena
Robson, 1929 [1]
Type species
Hapalochlaena lunulata
Quoy & Gaimard, 1832
Species

Blue-ringed octopuses, comprising the genus Hapalochlaena, are four extremely venomous species of octopus that are found in tide pools and coral reefs in the Pacific and Indian oceans, from Japan to Australia. [2] They can be identified by their yellowish skin and characteristic blue and black rings that can change color dramatically when the animal is threatened. They eat small crustaceans, including crabs, hermit crabs, shrimp, and other small sea animals.

They are one of the world's most venomous marine animals. [3] Despite their small size—12 to 20 cm (5 to 8 in)—and relatively docile nature, they are very dangerous if provoked when handled because their venom contains a powerful neurotoxin called tetrodotoxin.

The species tends to have a lifespan of approximately two to three years. This may vary depending on factors such as nutrition, temperature, and the intensity of light within its environment.

Classification

The genus was described by British zoologist Guy Coburn Robson in 1929. [4] There are four confirmed species of Hapalochlaena, and six possible but still undescribed species being researched: [5]

Behavior

Blue-ringed octopuses spend most of their time hiding in crevices while displaying effective camouflage patterns with their dermal chromatophore cells. Like all octopuses, they can change shape easily, which allows them to squeeze into crevices much smaller than themselves. This, along with piling up rocks outside the entrance to its lair, helps safeguard the octopus from predators.

Variable ring patterns on mantles of Hapalochlaena lunulata Variable ring patterns on mantles of the blue-ringed octopus Hapalochlaena lunulata.png
Variable ring patterns on mantles of Hapalochlaena lunulata

If they are provoked, they quickly change color, becoming bright yellow with each of the 50–60 rings flashing bright iridescent blue within a third of a second as an aposematic warning display. In the greater blue-ringed octopus (Hapalochlaena lunulata), the rings contain multi-layer light reflectors called iridophores. These are arranged to reflect blue–green light in a wide viewing direction. Beneath and around each ring are dark pigmented chromatophores which can be expanded within 1 second to enhance the contrast of the rings. There are no chromatophores above the ring, which is unusual for cephalopods as they typically use chromatophores to cover or spectrally modify iridescence. The fast flashes of the blue rings are achieved by using muscles which are under neural control. Under normal circumstances, each ring is hidden by contraction of muscles above the iridophores. When these relax and muscles outside the ring contract, the iridescence is exposed, thereby revealing the blue color. [7]

Similar to other Octopoda, the blue-ringed octopus swims by expelling water from a funnel in a form of jet propulsion.

Feeding

The blue-ringed octopus often feeds on fish and crustaceans. It pounces on its prey, seizing it with its arms and pulling it towards its mouth. It uses its horny beak to pierce through the tough crab or shrimp exoskeleton, releasing its venom. The venom paralyzes the muscles required for movement, which effectively kills the prey. [8]

Reproduction

The mating ritual for the blue-ringed octopus begins when a male approaches a female and begins to caress her with his modified arm, the hectocotylus. A male mates with a female by grabbing her, which sometimes completely obscures the female's vision, then transferring sperm packets by inserting his hectocotylus into her mantle cavity repeatedly. Mating continues until the female has had enough, and in at least one species, the female has to remove the over-enthusiastic male by force. Males will attempt copulation with members of their own species regardless of sex or size, but interactions between males are most often shorter in duration and end with the mounting octopus withdrawing the hectocotylus without packet insertion or struggle. [9]

Blue-ringed octopus females lay only one clutch of about 50 eggs in their lifetimes, towards the end of fall. Eggs are laid and then incubated underneath the female's arms for about six months. During this process, the female does not eat. After the eggs hatch, the female dies, and the new offspring will reach maturity and be able to mate by the next year.

Mating behavior

In the southern blue-ringed octopus, body mass is observed to be the strongest factor that influences copulatory rates. Evidence of female preference of larger males is apparent, although no male preference of females is shown. In this species, it is suggested that males expend more effort than females to initiate copulation. Additionally, it is unlikely that males use odor cues to identify females with which to mate. Male-male mounting attempts are common in H. maculosa, proposing that there is no discrimination between sex. Male blue-ringed octopus will adjust mating durations based on the female's recent mating history. Termination of copulation is not likely to happen with a female if she has not yet mated with another male. Duration length of mating is also found to be longer in these cases as well. [10]

Toxicity

The blue-ringed octopus, despite its small size, carries enough venom to kill 26 adult humans within minutes. Their bites are tiny and often painless, with many victims not realizing they have been envenomated until respiratory depression and paralysis begins. [11] No blue-ringed octopus antivenom is available. [12]

Venom

Blue-ringed octopus from New South Wales, Australia Blue-ringed-octopus.jpg
Blue-ringed octopus from New South Wales, Australia

The octopus produces venom containing tetrodotoxin, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine. The venom can result in nausea, respiratory arrest, heart failure, severe and sometimes total paralysis, blindness, and can lead to death within minutes if not treated. Death is usually from suffocation due to paralysis of the diaphragm. [13]

The venom is produced in the posterior salivary gland of the octopus by endosymbiotic bacteria. [14] [15] The salivary glands possess a tubuloacinar exocrine structure and are located in the intestinal blood space.[ citation needed ]

The major neurotoxin component of the blue-ringed octopus is a compound originally known as 'maculotoxin'; in 1978, this maculotoxin was found to be tetrodotoxin, [16] a neurotoxin also found in pufferfish, rough-skinned newts, and some poison dart frogs; the blue-ringed octopus is the first reported instance in which tetrodotoxin is used as a venom. [17] Tetrodotoxin blocks sodium channels, causing motor paralysis and respiratory arrest within minutes of exposure. The octopus's own sodium channels are adapted to be resistant to tetrodotoxin. [18] The tetrodotoxin is produced by bacteria in the salivary glands of the octopus. [19]

Direct contact is necessary to be envenomated. Faced with danger, the octopus's first instinct is to flee. If the threat persists, the octopus will go into a defensive stance, and display its blue rings. If the octopus is cornered and touched, it may bite and envenomate its attacker. [20]

Estimates of the number of recorded human fatalities caused by blue-ringed octopuses vary, ranging from seven to sixteen deaths; most scholars agree that there have been at least eleven. [21]

Tetrodotoxin can be found in nearly every organ and gland of its body. Even sensitive areas such as the Needham's sac, branchial heart, nephridia, and gills have been found to contain tetrodotoxin, and it has no effect on the octopus's normal functions. [22] This may be possible through a unique blood transport. The mother will inject the neurotoxin (and perhaps the toxin-producing bacteria) into her eggs to make them generate their own venom before hatching. [23]

Effects

Tetrodotoxin causes severe and often total body paralysis. Tetrodotoxin envenomation can result in victims being fully aware of their surroundings but unable to move. Because of the paralysis, they have no way of signaling for help or indicating distress. The victim remains conscious and alert in a manner similar to the effect of curare or pancuronium bromide. This effect is temporary and will fade over a period of hours as the tetrodotoxin is metabolized and excreted by the body.

The symptoms vary in severity, with children being the most at risk because of their small body size.

Treatment

First aid treatment is pressure on the wound and artificial respiration once the paralysis has disabled the victim's respiratory muscles, which often occurs within minutes of being bitten. Because the venom primarily kills through paralysis, victims are frequently saved if artificial respiration is started and maintained before marked cyanosis and hypotension develop. Respiratory support until medical assistance arrives will improve the victim's chances of survival. [24] [20] Definitive hospital treatment involves placing the patient on a ventilator until the toxin is removed by the body. [20] Victims who survive the first 24 hours usually recover completely. [25]

Conservation

Currently, the blue-ringed octopus population information is listed as Least Concern according to the International Union for the Conservation of Nature (IUCN). [26] However, threats such as bioprospecting, habitat fragmentation, degradation, overfishing, and human disturbance, as well as species collections for aquarium trade, may be threats to population numbers. It is possible that Hapalochlaena contributes to a variety of advantages to marine conservation. This genera of octopus provides stability of habitat biodiversity as well as expanding the balance of marine food webs. Various species of blue-ringed octopus may help control populations of Asian date mussels. Additionally, future research on tetrodotoxins produced by the blue-ringed octopus may produce new medicinal discoveries. [27]

In the 1983 James Bond film Octopussy , the blue-ringed octopus is the prominent symbol of the secret order of female bandits and smugglers, appearing in an aquarium tank, on silk robes, and as a tattoo on women in the order. [28] [2] The Adventure Zone featured a blue-ringed octopus in its "Petals to the Metal" series. [29]

Related Research Articles

<span class="mw-page-title-main">Octopus</span> Soft-bodied eight-limbed order of molluscs

An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.

<span class="mw-page-title-main">Venom</span> Toxin secreted by an animal

Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved venom apparatus, such as fangs or a stinger, in a process called envenomation. Venom is often distinguished from poison, which is a toxin that is passively delivered by being ingested, inhaled, or absorbed through the skin, and toxungen, which is actively transferred to the external surface of another animal via a physical delivery mechanism.

<span class="mw-page-title-main">Cephalopod</span> Class of mollusks

A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.

<span class="mw-page-title-main">Tetrodotoxin</span> Neurotoxin

Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish, it is found in several other animals. It is also produced by certain infectious or symbiotic bacteria like Pseudoalteromonas, Pseudomonas, and Vibrio as well as other species found in symbiotic relationships with animals and plants.

<span class="mw-page-title-main">Blue-lined octopus</span> Species of venomous cephalopod

The blue-lined octopus is one of four species of highly venomous blue-ringed octopuses. It can be found in Pacific Ocean waters that stretch from Australia to Japan. It is most commonly found around intertidal rocky shores and coastal waters to a depth of 15 metres (49 ft) between southern Queensland and southern New South Wales. It is relatively small, with a mantle up to 45 millimetres (1.8 in) in length. In its relaxed state, it is a mottled yellow-brown with dark blue or black streaks covering the whole body apart from the underside of its arms, but its vibrant blue markings appear as a warning to predators when it feels threatened. Along with its other closely related species, the blue-lined octopus is regarded as one of the most dangerous animals in the sea, and its venom can be fatal to humans. This benthic octopus is one of four members of the genus Hapalochlaena, with the other species being the greater blue-ringed octopus, southern blue-ringed octopus, and the blue-ringed octopus. The blue-lined octopus is the only species of the four to display lined iridescent blue marking, as opposed to circular iridescent blue marking that the three other species tend to exhibit.

<span class="mw-page-title-main">Snake venom</span> Highly modified saliva containing zootoxins

Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom.

<span class="mw-page-title-main">Saxitoxin</span> Paralytic shellfish toxin

Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin (PST). Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic shellfish poisoning (PSP).

<i>Crotalus scutulatus</i> Species of snake

Crotalus scutulatus is known commonly as the Mohave Rattlesnake. Other common English names include Mojave Rattlesnake and, referring specifically to the nominate (northern) subspecies: Northern Mohave Rattlesnake and Mojave Green Rattlesnake, the latter name undoubtedly acquiescing to the widely used colloquial name “Mojave green”. Campbell and Lamar (2004) supported the English name “Mohave (Mojave) rattlesnake” with some reluctance because so little of the snake’s range lies within the Mojave Desert.

<span class="mw-page-title-main">Chinese red-headed centipede</span> Subspecies of centipede

The Chinese red-headed centipede, also known as the Chinese red head, is a centipede from East Asia. It averages 20 cm (8 in) in length and lives in damp environments.

<span class="mw-page-title-main">Indian cobra</span> Species of snake

The Indian cobra, also known commonly as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of cobra, a venomous snake in the family Elapidae. The species is native to the Indian subcontinent, and is a member of the "big four" species that are responsible for the most snakebite cases in India.

<span class="mw-page-title-main">Southern blue-ringed octopus</span> Species of mollusc

The southern blue-ringed octopus is one of three highly venomous species of blue-ringed octopuses. It is most commonly found in tidal rock pools along the south coast of Australia. As an adult, it can grow up to 20 centimetres (8 in) long and on average weighs 26 grams (0.9 oz). They are normally a docile species, but they are highly venomous, possessing venom capable of killing humans. Their blue rings appear with greater intensity when they become aggravated or threatened.

<span class="mw-page-title-main">Greater blue-ringed octopus</span> Species of venomous cephalopod

The greater blue-ringed octopus is one of four species of extremely venomous blue-ringed octopuses belonging to the family Octopodidae. This particular species of blue-ringed octopus is known as one of the most toxic marine animals in the world.

<i>Sepioloidea lineolata</i> Species of cuttlefish

Sepioloidea lineolata or more commonly known as the striped pyjama squid or the striped dumpling squid is a type of bottletail squid that inhabits the Indo-Pacific Oceans of Australia. Although traditionally falling within Sepiida, the cuttlefish order, it lacks a cuttlebone. More recent phylogenomic evidence suggests bottletail and bobtail squid may form their own order, Sepiolida. The striped pyjama squid lives on the seafloor and is both venomous and poisonous. When fully mature, a striped pyjama squid will only be about 7 to 8 centimetres in length. Baby striped pyjama squid can be smaller than 10 millimetres (0.39 in).

<i>Wunderpus photogenicus</i> Species of cephalopod

Wunderpus photogenicus, the wunderpus octopus, is a small-bodied species of octopus with distinct white and rusty brown coloration. 'Wunderpus' from German “wunder” meaning ‘marvel or wonder’.

<i>Octopus bimaculatus</i> Species of octopus

Octopus bimaculatus, commonly referred to as Verrill's two-spot octopus, is a similar species to the Octopus bimaculoides, a species it is often mistaken for. The two can be distinguished by the difference in the blue and black chain-like pattern of the ocelli. O. bimaculatus hunt and feed on a diverse number of benthic organisms that also reside off the coast of Southern California. Once the octopus reaches sexual maturity, it shortly dies after mating, which is approximately 12–18 months after hatching. Embryonic development tends to be rapid due to this short lifespan of these organisms.

Abdopus capricornicus is a species of octopus in the family Octopodidae, and is often also referred to as Octopus capricornicus. This octopus is native to the Great Barrier Reef and is often found throughout the Indo-West Pacific Ocean. There are six other species of octopuses within the subgenus Abdopus with a large number of organisms not yet described. This octopus is notable for its unique body patterning through which it can change. The likely uses for this characteristic are camouflage or intraspecific communication. Other organisms in the Abdopus genus include A. horridus, A. abaculus, A. aculeatus, and A. tonganus. Individuals are capable of autotomy, sacrificing a writhing arm to a predator to distract it while making an escape.

<span class="mw-page-title-main">Toxungen</span>

Toxungen comprises a secretion or other body fluid of one or more biological toxins that is transferred by one animal to the external surface of another animal via a physical delivery mechanism. Toxungens can be delivered through spitting, spraying, or smearing. As one of three categories of biological toxins, toxungens can be distinguished from poisons, which are passively transferred via ingestion, inhalation, or absorption across the skin, and venoms, which are delivered through a wound generated by a bite, sting, or other such action. Toxungen use offers the evolutionary advantage of delivering toxins into the target's tissues without the need for physical contact.

Octopus bocki is a species of octopus, which has been located near south Pacific islands such as Fiji, the Philippines, and Moorea and can be found hiding in coral rubble. They can also be referred to as the Bock's pygmy octopus. They are nocturnal and use camouflage as their primary defense against predators as well as to ambush their prey. Their typical prey are crustaceans, crabs, shrimp, and small fish and they can grow to be up to 10cm in size.

References

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  2. 1 2 Craft, Lucy (1 July 2013). "Tiny but deadly: Spike in blue-ringed octopus sightings sparks fear of invasion in Japan". CBS News. Retrieved 23 January 2018.
  3. ↑ "Ocean's Deadliest: The Deadliest Creatures – Greater Blue-Ringed Octopus". Animal Planet. Archived from the original on 18 February 2009.
  4. ↑ Robson, G.C. (June 1929). "LXXIII.— Notes on the Cephalopoda .—VIII. The genera and subgenera of Octopodinæ and Bathypolypodinæ". Annals and Magazine of Natural History. 3 (18): 607–608. doi:10.1080/00222932908673017.
  5. 1 2 Sethi, S. N.; Rudramurthy, N. (2013). "Blue ring Octopus, Hapalochlaena nierstraszi, from the Bay of Bengal along the Chennai Coast". Fishing Chimes. 33 (8): 82–83.
  6. ↑ Allcock, L.; Taite, M. (2018). "Hapalochlaena nierstraszi". IUCN Red List of Threatened Species . 2018: e.T163395A1004594. doi: 10.2305/IUCN.UK.2018-2.RLTS.T163395A1004594.en . Retrieved 7 November 2022.
  7. ↑ Mäthger, L.M.; Bell, G.R.; Kuzirian, A.M.; Allen, J.J. & Hanlon, R.T. (2012). "How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?". The Journal of Experimental Biology. 215 (21): 3752–3757. doi: 10.1242/jeb.076869 . PMID   23053367.
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  10. ↑ Morse, Peter; Zenger, Kyall R.; McCormick, Mark I.; Meekan, Mark G.; Huffard, Christine L. (2015). "Nocturnal mating behaviour and dynamic male investment of copulation time in the southern blue-ringed octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)" (PDF). Behaviour. 152 (14): 1883–1910. doi:10.1163/1568539X-00003321.
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  15. ↑ Laidlaw, Shawn (2 October 2020). "Blue Ringed Octopus - Facts and Beyond". Biology Dictionary.
  16. ↑ Sheumack DD, Howden ME, Spence I, Quinn RJ (1978). "Maculotoxin: a neurotoxin from the venom glands of the octopus Hapalochlaena maculosa identified as tetrodotoxin". Science. 199 (4325): 188–9. Bibcode:1978Sci...199..188S. doi:10.1126/science.619451. PMID   619451.
  17. ↑ Daly, J.W.; Gusovsky, F.; Myers, C.W.; Yotsuyamashita, M. & Yasumoto, T. (1994). "1st Occurrence of Tetrodotoxin in a Dendrobatid Frog (Colostethus inguinalis), with Further Reports for the Bufonid Genus Atelopus". Toxicon. 32 (3): 279–285. doi:10.1016/0041-0101(94)90081-7. PMID   8016850.
  18. ↑ Geffeney, Shana L.; Williams, Becky L.; Rosenthal, Joshua J.C.; Birk, Matthew A.; Felkins, Justin; Wisell, Christine M.; Curry, Eveningstar R.; Hanifin, Charles T. (2019). "Convergent and parallel evolution in a voltage-gated sodium channel underlies TTX-resistance in the Greater Blue-ringed Octopus: Hapalochlaena lunulata". Toxicon. 170: 77–84. doi: 10.1016/j.toxicon.2019.09.013 . PMID   31550451. S2CID   202761604.
  19. ↑ Caldwell, Roy. "What makes blue-rings so deadly?" . Retrieved 19 March 2007.
  20. 1 2 3 "Blue-Ringed Octopus". Divers Alert Network. Retrieved 18 March 2019.
  21. ↑ Burnett, Joseph W.; Burnett, Joseph; Rifkin, Jacqueline F. (1996). Venomous and Poisonous Marine Animals: A Medical and Biological Handbook. UNSW Press. ISBN   978-0-86840-279-6.[ page needed ]
  22. ↑ Caldwell, R.; Stark, Michael; Williams, B. L. (2012). "Microdistribution of tetrodotoxin in two species of blue-ringed octopuses (Hapalochlaena lunulata and Hapalochlaena fasciata) detected by fluorescent immunolabeling". Toxicon. 60 (7): 1307–1313. doi:10.1016/j.toxicon.2012.08.015. PMID   22983011.
  23. ↑ Becky L. Williams; Charles T. Hanifin; Edmund D. Brodie Jr.; Roy L. Caldwell (2011). "Ontogeny of Tetrodotoxin Levels in Blue-ringed octopuses: Maternal Investment and Apparent Independent Production in Offspring of Hapalochlaena lunulata". Journal of Chemical Ecology. 37 (1): 10–17. Bibcode:2011JCEco..37...10W. doi:10.1007/s10886-010-9901-4. PMID   21165679. S2CID   11624429.
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  25. ↑ Lippmann, John and Bugg, Stan (2004) DAN S.E. Asia-Pacific Diving First Aid Manual, J.L. Publications, Australia. ISBN   0-646-23183-9 [ page needed ]
  26. ↑ Allcock, L.; Taite, M.; Allen, G. (2018). "Hapalochlaena lunulata". IUCN Red List of Threatened Species . 2018: e.T163293A994503. doi: 10.2305/IUCN.UK.2018-2.RLTS.T163293A994503.en . Retrieved 7 November 2022.
  27. ↑ Lambert, William A. (2011). A Review of Blue-ringed Octopus Conservation (Thesis). ISBN   978-1-124-64712-8. OCLC   778566691. ProQuest   871101826.
  28. ↑ "Octopussy (1983)". IMDb.
  29. ↑ "Ep. 24. Petals to the Metal – Chapter Seven". Maximum Fun. 24 September 2015. Retrieved 19 September 2016.
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