Frogs with a venomous head butt

SNIPPETS

There are many poisonous frogs — eat the wrong frog legs at a Paris bistro, and you are in trouble. Now researchers have discovered two venomous frogs that deliver potent toxins through bony spines on their heads. “It was thought that frogs were completely passive,” said Edmund Brodie, a biologist at Utah State University.

“In this case, the frog is doing some serious injuring.” Edmund and his colleagues reported their findings in the journal Current Biology. The two venomous species, Corythomantis greeningi and Aparasphenodon brunoi, are found in Brazil but have not been well studied. Edmund’s colleague and co-author, Carlos Jared, a biologist at the Instituto Butantan in Brazil, was collecting specimens when one of the frogs jabbed him with its spines. “He had intense pain radiating up the arm lasting for five hours,” Edmund said. “That was the eureka moment.”

Luckily, Carlos was jabbed by C. greeningi. A single gram of toxic secretion from A. brunoi is enough to kill 300,000 mice or about 80 people, according to the researchers’ calculations. It is unlikely that a small frog can deliver a gram of venom in a single jab, but the researchers are planning to err on the side of caution, Edmund said.

Chimpanzees using clay as food

Wild chimpanzees in Uganda have begun eating clay, which furnishes dietary minerals to them, a new study reports. “I had never seen this, and I have been observing them since 1962,” said Vernon Reynolds, a professor emeritus of biological anthropology at Oxford University and an author of the study, published in PLOS One. “Now, just recently, they are really going for it in a big way.”

The researchers studied chimpanzees living in the Budongo Forest. Vernon and his colleagues believe the chimps have turned to clay because of the widespread destruction of local raffia palm trees. The chimpanzees used to eat the decayed pith of the tree, which contains minerals. The clay they have begun eating has “plenty of aluminium in it, high concentrations of iron, lots of manganese, magnesium and potassium,” Vernon said, “It is a cocktail of minerals.”

Raffia trees are being killed by local tobacco farmers, who strip the trees of leaves for use in curing and drying tobacco. The chimpanzees also relied on raffia palm trees as a source of sodium, but the clay does not have high sodium levels, Vernon said. “We do not know how they have replaced it,” he said. “But they are not short of salt, or else they would show signs of deterioration.”

Honeybees show evidence of insecticide

More than 70 per cent of pollen and honey samples collected from foraging bees in Massachusetts contained neonicotinoids, a type of insecticide that has been linked to colony collapse disorder, researchers reported last week.

The disorder causes adult bees to abandon their hives in winter. In the new study, published in The Journal of Environmental Chemistry, researchers analysed 219 pollen samples and 53 honey samples from 62 hives in 10 counties in Massachusetts. Honeybee colonies have experienced significant losses over the last decade, and the effects can be far-reaching: Bees are the prime pollinators of one-third of all crops worldwide.