Poisonous Animals

8/01/2014Masahiro Yakeya

Professor ： Christopher YUKNA

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Contents

What is Redback SpiderHabitatsTheir figureTheir lifecycleVenomSymptomTreatment and careConclusion

What is Redback Spider?

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Adult female

Adult male

The redback spider (Latrodectus hasseltii), also known as the jockey spider, is a species of poisonous spider indigenous to Australia.

The redback is one of the few spider species that can be seriously harmful to humans, and its preferred habitat has led it to being responsible for the large majority of serious spider bite in Australia.

Habitats

Australia

Southeast Asia

Distribution Areas

Japan

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Red pattern on the back

Color and shapeRed pattern also stomach

Fang(0.7mm)

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Even if bitten from the top of the clothes, it does not reach the skin.

Size

Male

FemaleMale : 3~5mmFemale : 10~15mm

Female only has a poison, there is no poison in the male.

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Where does Redback Spider Live?• Sunny, warm place• Where there is plenty of food, such as insects or small animals• Where there is a suitable gap to put the nest

The back of groove Fence Under the planter7

What does Redback Spider eat?

They can survive for 100 days without any food.

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Lifecycle of Redback Spider

JuvenileAdult

Eggs

Internal sac of one egg : 100~200

Egg sac

Male : 58~75 daysFemale : 75~104 days

They work in June-September

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Their venomVenom is produced by glands in the cephalothorax, and expelled venom travels through paired ducts from the cephalothorax, exiting through the tip of the spider's hollow fangs.

Venomgland

Fang

Venom protein

Muscular layerFang and venom gland of redback spider

Microstructure of venom gland of redback spider10

Component of the venomName : α-latrotoxin (neurotoxin)

King Cobra : 1.75mg/kgRedback Spider : 0.59mg/kg

Features of α-latrotoxinThe only toxic to vertebrateToxin which is effective in the presynaptic

membraneToxic effect of promoting the depolarization of

the central nervous system of vertebratesTOXICITY (Comparison of LD50)

Their poison is stronger than snake’s it.11

Actions of α-latrotoxinα-latrotoxin is allowed to flow to force the Ca ion by acting from outside the neuron to calcium channels of axon terminals.

Neurotransmitter is released all and we provoke such seizures abnormally excited the muscle fibers or neurons

Information transmission function of the nervous system is paralyzed.

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SymptomImmediately after being bitten

When redback spider bites, almost no pain topical immediately after being bitten and only feel a slight pain at a site bitten even. In some cases, stab mouth is found one or two.

5~60 minutes after being bitten

Local symptoms appear, pain will increase gradually.

60 minutes~ after being bitten

Pain bitten over time spread to the entire limb. Local sweating also occur, warmth, itching also often associated with. However, the greatest feature of the local symptoms is pain.

There are example that people died by anaphylactic shock.

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If we are bitten…

We don’t die by their poison because injection amount of their poison is a little.

If the treatment is delayed, we cause muscle paralysis or skin rot.

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Bite treatment and care If we are bitten by redback spider, we have to

wash the area of the bite with soap and water.

Even if there is bleeding, it is not necessary to the tourniquet and bandage.

Chilled on ice the wound, to go to the hospital.

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How to removeIf you found a redback spider, you must not touch it with bare hands.

Spraying Stomping Burning

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Conclusion The adult female redback spider has a round body about 1 cm long, with long, slender legs. The body is a deep black (occasionally brownish), with a red (sometimes orange) longitudinal stripe on the upper abdomen.

The poison that they have is very strong to the vertebrate. However, if you do not do anything for them, they will not bite.

If we are bitten by them, appropriate care is necessary.

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Thank you!!

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History of Redback spider①1870 : Swedish aracheologist Tamerlan Thorell

described the redback spider from specimens collected in Rockhampton and Bowen in central Queensland

He named it Latrodectus hasselti in honour of collegue A.W.M van Hasselt.

1902 :German arachnologist Friedrich Dahl revised the genus and named L.ancorifer from New Guinea, which was later regarded as a subspecies of the redback.

1911 : Another subspecies , L. h. aruensis , was described by 

Norwegian entomologist Embrik Strand. 20

History of Redback spider②1959 : Arachnologist Herbert Walter Levi revised the

genus Lactrodectus.

He focused on differences in the morphology of the female sexual organs, he reclassified the genus reducing the number of recognized species from 22 to 6.

~Recently : More reliable genetic studies have split the genus into about 30 species, and the redback has no recognized subspecies in modern classifications.

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Nest of Redback spiderThe nest that they build is irregular and have a three-dimensional structure strung complicated.

Nest area

Capture area

Mucus of capturing is attached to the thread.

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Fatal caseRedback spider bites rarely cause chronic morbidity , and deaths are even more rare.  Throughout the history, at least 14 deaths from redbacks have been recorded.  Children, the elderly, or those with serious medical conditions are at much higher risk of severe effects and death resulting from a bite.

DangerousDangerou

s

Dangerous

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Relationship with humansTheir net is used to cross line of optical instruments surveying instruments, rangefinder, microscope, bombsight, such as telescopic sight.

The study that made full use of genetic engineering, and a thread of this spider is produced to bacteria is going by the fund of the United States Army.

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Japanese spider

Chiracanthium japonicum(kabakikomachigumo)

Latrodectus mactans(kurogokegumo)

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