Blue-ringed octopus
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Great blue-ringed octopus ( Hapalochlaena lunulata ) |
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| Hapalochlaena | ||||||||||
| Robson , 1929 | ||||||||||
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The blue-ringed octopus ( Hapalochlaena ) form a genus of octopus that includes four species . In terms of lifestyle and body shape, they are relatively typical representatives of the octopus, which belong to the cephalopods .
The Hapalochlaena species live off the coast of Australia , the Philippines , Indonesia and New Guinea , where they prefer the shallow coastal area up to a depth of about 50 meters. They also stay relatively often near the shore. You can meet them both in the reef and on the flat shelf . Encounters with the animal are particularly frequent in small tide pools on the bank or in floating debris where they hunt for crabs . The octopuses have an intense color, which they show especially when threatened, and which consists of bright blue rings ( H. maculosa , H. lunulata ) or stripes ( H. fasciata ), which are clearly set off on the yellowish body.
Reproduction and development
The females of the blue-ringed octopus lay eggs only once in their life, which they stick to sheltered places or carry around and guard. After the young hatch, the mothers die. The fathers die shortly after mating. As with all other cephalopods, there are no planktonic larvae here; the young hatch as small, ready-made octopuses.
Aposematism
As aposematism an abnormality is called, at which toxic to present animals.
Toxicity
All species of this genus have a strong toxin that they release when bitten and that can also be fatal for humans. It is a neurotoxin , tetrodotoxin (TTX), also known under the name maculotoxin or tarichatoxin, which some other animals (including puffer fish , stubby frogs , some crabs and snails ) have. However, this poison is not produced by the octopus itself, but by bacteria that live in the foregut and the salivary glands of the octopus and are passed on to the offspring. The following bacteria were detected in Hapalochlaena maculosa : Alteromonas spp. , Bacillus spp. , Pseudomonas spp. and Vibrio spp. TTX-producing bacteria have also been found in the eggs of this octopus.
The poison works relatively quickly; paralysis occurs within two hours of a bite, especially in the chest muscles and the diaphragm , resulting in respiratory arrest and ventricular fibrillation . The most important treatment is ventilation until the effects of the poison wear off. If ventilation is carried out properly, the person affected can survive without further damage.
Warning color
Blue-ringed octopuses have a coloration that could be interpreted both as a body-dissolving camouflage and as a warning coloration , which is made probable by the richness of contrast.
Warning behavior
The body muscles of the octopus can pulsate the ring-shaped pattern when threatened, which gives a clearly visible warning effect.
species
The following species are known, but it is very likely that other species exist:
Hapalochlaena lunulata - Large blue-ringed octopus
The great blue-ringed octopus is the best-known representative of the genus. He lives in northern Australia, Papua New Guinea , the Solomon Islands , Indonesia and the Philippines as far as Sri Lanka . Its body reaches a maximum length of 55 mm (without arms) and has a brown basic color. Large, bright blue rings are on the back and arms; each of the rings is bordered by a ring of dark colored cells. Another bright blue line runs through the eyes. The name Great Blue Ringed Octopus refers to the size of the rings, not the body size.
Hapalochlaena maculosa - Small blue-ringed octopus
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This species, also known under the name Octopus maculosus , lives exclusively on the coast of South Australia from southern Western Australia to eastern Victoria . The basic color of the animal is a brownish beige with large, darker spots. The arms are also banded with such surfaces. No blue rings are visible on the body when it is at rest. This changes when the animal becomes irritated. Then the dark spots and bands suddenly become even darker and bright blue rings appear on them, which are significantly smaller, but more numerous than in the first described species.
Hapalochlaena fasciata - blue-striped octopus
This octopus can be found in southeast Australia, from New South Wales to Queensland . The animal is uniformly light beige colored when it is at rest, dark spots and blue lines are invisible. When excited, the entire octopus becomes dark and extremely dark spots appear on its body, as in Hapalochlaena maculosa , bright blue stripes appear in the spots. Individual stripes and rings are also visible on the arms.
Hapalochlaena nierstraszi
This species was described in 1938. Since only the type specimen from the Gulf of Bengal and one other specimen caught in 2012 are known, it is doubtful whether it is actually a valid species.
literature
- DF Hwang, O. Arakawa, T. Saito, T. Noguchi, U. Simidu, K. Tsukamoto, Y. Shida and K. Hashimoto: Tetrodotoxin-producing bacteria from the blue-ringed octopus Octopus maculosus In: Marine Biology , Volume 100 , No. 3, 1989, pp. 327-332.
Web links
Individual evidence
- ↑ Becky L. Williams, Charles T. Hanifin, Edmund D. Brodie Jr., Roy L. Caldwell: Ontogeny of tetrodotoxin levels in blue-ringed octopuses: Maternal investment and apparent independent production in offspring of Hapalochlaena lunulata. In: Journal of Chemical Ecology 37, No. 1, 2011, pp. 10-17, doi : 10.1007 / s10886-010-9901-4 .
- ↑ Robert Frangez, Marjana Grandić, Milka Vrecl: Cardiovascular pathophysiology produced by natural toxins and Their possible therapeutic implications. In: M. Fiuza (Ed.): Cardiotoxicity of Oncologic Treatments InTech, 2012, pp. 1-16.
- ↑ Yfke Hager: Blue-ringed octopus flexes muscles to flash fast warning signals. In: The Journal of Experimental Biology , 2012.