Coleoptera
There are beetles poisonous?
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The beetles do not have a sting and cannot kill you.
Beetles do not attack life animals.

Most poisonous beetles:

An African leaf beetle, Diamphidia simplex (Chrysomelidae), exudes a poison that causes death by paralysis. African bushmen use this poison on their arrow tips to kill animals.

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There are beetles which contain poison.
Many species, including Coccinelidae (lady beetles) and Meloidee (Blister beetles), can secrete poisonous substances to make them unpalatable.

Crushed some of poisonous beetles can kill animals or man.

Carabidae -
Beetles-bombardiers really deserve the name a “chemical lab”. They have two glands secreting poisoning substances. Each one is parted in two chambers and one common antechamber, the latter of which secrete two enzymes. When the beetle is in danger, great amount of substances secreted in the both chambers get into the antechamber, where runs a rapid chemical reaction. The temperature rises to 100º and the beetle fires the liquid through his anus in up to 30 cm distance with an enviable archery skill. Some species can produce 15-20 consequent shots. The poison is extremely dangerous for the eyes and the mucous membrane.

Meloidae - Blister beetles

Cantharidin is the poisonous substance in blister beetles. It is comparable to cyanide and strychnine in toxicity. Although horses are considered to be very susceptible, comparable doses can poison cattle or sheep. Very small amounts of cantharidin can cause colic in horses. The substance is very stable and remains toxic in dead beetles. Animals may be poisoned by ingesting beetles in cured hay. There is no sampling method that can detect toxic levels of blister beetles in cured hay.
Cantharidin can cause severe skin inflammation and blisters. It is absorbed through the intestine and can cause symptoms such as inflammation, colic, straining, elevated temperature, depression, increased heart rate and respiration, dehydration, sweating, and diarrhea. There is frequent urination during the first 24 hours after ingestion, accompanied by inflammation of the urinary tract. This irritation may also result in secondary infection and bleeding. In addition, calcium levels in horses may be drastically lowered and heart muscle tissues destroyed. Since animals can die within 72 hours, it is imperative to contact a veterinarian as soon as blister beetle poisoning is suspected.
How many beetles does it take to kill a horse? It depends. The concentration of cantharidin varies with the species of beetle as well as sex. The chemical is produced by the male, which has the highest content; some is passed to the female during mating. Cantharidin content of the striped blister beetle has been measured to be about 5 times greater that the level found in the black blister beetle. The amount of cantharidin necessary to kill a horse is estimated at 1 milligram of cantharidin per kilogram of horse weight. For example, this translates to about 25 striped blister beetles for a 275 pound horse to over 100 for a 1200 pound animal. About 250 and 1,100 of the less toxic black blister beetles would be needed for the same two animal weights.

(source L.H.Townsend, University of Kentucky)

genus Epicauta, Lytta

ACADEMY RESEARCH: A Powerful Poison
Academy scientist Dr. Jack Dumbacher recently solved an intoxicating question: where do toxic birds and poison-dart frogs acquire their potent poisons?

In 1992, after hearing from local people in New Guinea about a bird called a Pitohui that caused burning or numbing sensations if it was eaten, Dumbacher tested the skin and feathers of the species and detected the presence of neurotoxins. This finding presented the first known example of chemical defense among birds. The results became even more intriguing when Dumbacher and his colleagues learned that the toxin in question had only been found in nature once before - in Colombia 's poison-dart frogs. Over the next several years, Dumbacher found varying levels of batrachotoxins in five species of birds from the genus Pitohui , as well as in one species from the genus Ifrita . His data showed that the concentration of toxins in a bird's skin and feathers varied not only by species, but also by geographic location, suggesting that the birds - like the poison-dart frogs - were acquiring batrachotoxins from an environmental source. Since then, Dumbacher has been working with colleagues from the Smithsonian Conservation Research Center and the National Institutes of Health to determine which plant or insect may be responsible for producing the poison.
Their mission has been mammoth by any measure - New Guinea is home to over 700,000 known species of insects and about 15,000 plant species. Dumbacher attempted to probe the most promising suspects first by conducting stomach analyses on poisonous Pitohuis and Ifrita birds and then testing any identified species for toxins. He also talked to local villagers and asked them to point out any plants or insects they knew to cause burning or numbing sensations. He found the proverbial needle in the hay stack when villagers from Herowana pointed out a beetle from the genus Choresine that they called a nanisani. According to these local naturalists, the name"nanisani" refers specifically to the unusual numbing and tingling sensations to the lips and face that are caused by contact with one of these beetles. They also use"nanisani" as a name for the poisonous Ifrita bird. Dumbacher sent some of these beetles out for analysis, and test results confirmed that they contained batrachotoxins, making them a possible direct source of toxin for New Guniea's poisonous birds.
Dumbacher and his colleagues have yet to collect extensive stomach analysis data that would directly link the beetles to the birds, but in the tests they have run so far, they have already found a Choresine beetle in the stomach of a Pitohui. They have also found a number of Choresine-sized insects in both Pitohui and Ifrita specimens, suggesting that both types of birds likely acquire their poison from the beetles. The alternative hypothesis that both the birds and the beetles are acquiring their poison from a third source, such as a plant, is unlikely, since the Ifrita seems to be exclusively insectivorous. Choresine beetles belong to the Melyridae family - a family that is also found in the rain forests of Colombia. Thus, relatives of the"nanisani" beetles are a likely source of the batrachotoxins found in Colombia's poison-dart frogs
(from California academy of sciences)

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Last modified on Thursday, 25 July 2013