Jack Dumbacher recently solved an intoxicating question: where do toxic birds and poison-dart frogs acquire their potent poisons? In , 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 , known species of insects and about 15, 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.
David Rivers, Ph. When Rivers co-authored a textbook, The Science of Forensic Entomology, published earlier this year, he included a chapter about insects that produce toxins that can kill people under certain circumstances.
Loyola magazine invited Rivers to introduce us to a few of the deadliest insects in the world, and he was happy to comply. In that regard, we do have some that are close by: There are two, and they are both ant species. But if the cow steps on any, a chemical signal in the venom gland, an alarm pheromone, is released that mobilizes the colony for group attack.
Known in the southwestern United States since the s, red fire ants have been on a northern expansion which is projected to reach Maryland someday. When the USDA tried to kill them in Florida flooding with fire hoses, the ants made a watertight ball with the queen in the middle, and it floated on the water.
Patients were dying and nurses and nursing assistants were accused of murdering patients. Blister beetles : These beetles feed on crops and gardens, so human contact is likely.
They are also attracted to light, making your patio another area to be cautious of this beetle. When the bite happens, the beetle releases a chemical substance that can cause the skin to blister. The blister usually heals within a few days and causes no permanent damage. Stag beetles : They are black to dark-brown and have large mandibles. The male does not have enough strength in his jaws to bite, however, the female does.
A bite from the female can be painful, but does not normally require any medical treatment. Longhorned beetles : These beetles are named for their unusually long antennae.
Longhorned beetles feed on firewood and timber with a high moisture content. Some species also feed on leaves, nectar and pollen. A bite from this type of beetle may cause considerable pain that could last up to a day or two. Fortunately, beetle bites are not common and they are seldom harmful to humans unless the person bitten has an allergic reaction.
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