Sunday, April 1, 2007

Honeybees learn to avoid toxic nectars

Why plants would try to poison the honeybees they wish to attract is a scientific mystery. Can honeybees learn whether nectar contains toxins? Dr Geraldine Wright (Newcastle University) will present data on how toxins in nectar affect a honeybee’s willingness to eat floral nectar on Sunday 1st April at the Society for Experimental Biology’s Annual Meeting in Glasgow.

Honeybees are very clever and can learn to associate almost any colour, shape, texture or scent with food. The newly-sequenced honeybee genome has revealed that honeybees do not have as many genes for taste receptors as other animals of a similar size, such as flies and mosquitoes. This prompted scientists to think that perhaps honeybees had a reduced need to detect and learn about toxins, despite the fact that some floral nectar contains toxins. Work carried out by Dr Wright and colleagues suggests that honeybees may have the ability to react to toxins, even if they cannot taste them.

Researchers found that both the sugar content and the toxins in nectar affected a honeybee’s memory for learned odours. Honeybees learned not to respond to odours associated with toxins within 20 min of eating toxins, and would retain this ability up to 24 hours after eating a toxin.

Friday, March 16, 2007

Chimps menstruation

Males and females of various species often manage when they have sex to influence their chances of having offspring. For instance, nearly all chimpanzee sex takes place when females are at the most fertile points of their menstrual cycles.

Curiously, females are known to sync up their menstrual cycles—and how fertile they are—in a number of primate species. Humans may synchronize menstrual cycles as well, although this remains controversial. Whether or not chimpanzees, the closest relatives of humans, sync up their menstrual cycles had been uncertain.

To shed light on this phenomenon, primatologist Akiko Matsumoto-Oda at Okinawa University and her colleagues investigated wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale Mountains National Park in Tanzania by the shores of Lake Tanganyika. There, Japanese researchers have studied the chimpanzees for more than 40 years.

After analyzing nine years of data, the team found chimps actually avoided synchronizing their fertility. The findings are detailed in the March issue of the journal Behavioral Ecology and Sociobiology.

Source :

Saturday, March 10, 2007

Gibbon songs : a clue to evolution of spoken language

wild gibbon in Thailand
Scientists discovered that wild gibbons in Thailand have crafted unique songs as alarm calls to other gibbons, a discovery that might shed light on the evolution of spoken language.

The sounds that animals make are traditionally thought of simply as signs of their basic mood. At times, however, animal sounds are used to communicate specific details about the world to others.

For instance, vervet monkeys give one kind of call if they see a snake, prompting others to search the ground, and another type of cry if they see an eagle, leading others to watch the sky, explained study team member Klaus Zuberbhler, a psychologist and primatologist at the University of St. Andrews in Scotland. This is known as "referential signaling."

Gibbons are known for their loud, elaborate songs every morning, often coordinating in duets with their mates. These can be heard up to miles away through dense forest.

Primatologists led by Esther Clarke of the University of St. Andrews observed white-handed gibbons at Khao Yai National Park in Thailand. To see how these primates might respond to predators, the researchers built fake animals that resembled typical gibbon predators.

The gibbons spend much of their lives on tree branches 60 to 100 feet off the ground. But when they spotted the models, which were usually just a few feet off the ground, they descended to within 15 or 30 feet of the predators and sang at them. The gibbon's approach might be "to alert a predator to the fact that it's been seen, and thus there's no point in hunting anymore."

Gibbon songs are crescendos of up to seven sounds dubbed notes, such as "wa" "hoo" and "waoo." The scientists found that while the gibbons used the same notes in all of their songs, they arranged the notes differently for duets and those to alarm predators, particularly in the first 10 notes of the songs. This is the first time such communication has been confirmed in free-ranging primates outside humans. The finding could have implications for the evoulution and development of human language.

Their evidence suggests the gibbons also sing different songs depending on the kind of predator, Zuberbhler said, but further research is needed to confirm this.

Full text report : The Syntax and Meaning of Wild Gibbon Songs
Related topics : Chimpanzees found to use tools to hunt mammalian prey

Wednesday, March 7, 2007

Ants Possess High Heat Tolerance - a clue to global warming

Michael Angilletta of Indiana State University, a U.S.-led team of international biologists, says some ants have adjusted to well to urban warming and may help other species adapt to such climate change.

The researchers note large cities can be more than 10 degrees hotter than their surroundings, with such urban heat islands stressing animals and plants.

The scientists discovered that ants in Sao Paulo, Brazil, South America's largest city, can tolerate heat better than ants from elsewhere. That finding suggests Sao Paulo ants have adjusted physiologically in response to urban warming.

"We don't know whether this pattern will hold up for other species or other cities, but people should certainly be looking," said Angilletta, an associate professor of ecology and organismal biology. "Ultimately, this research could help us to understand how species will respond to global climate change."

Read the journal atl PLoS ONE : Urban Physiology: City Ants Possess High Heat Tolerance

Saturday, March 3, 2007

Why Birds Migrate

birds migrateBirds migrate for food and to escape winter. Seasonal migration lets birds avoid cold seasons and exploit food sources available only certain times of the year. Many birds breed in the Arctic and feast on insect swarms there during the brief summer. Come fall, they return home to southlands: southern USA, Central America, or South America. We think of them as "our" birds that go south for the winter but they're really southern birds that fly north to breed.

It’s food scarcity, not dietary preferences, that motivates birds to migrate thousands of miles back and forth between breeding and non-breeding areas each year, new research shows.

“It’s not whether you eat insects, fruit, nectar or candy bars or where you eat them—it matters how reliable that food source is from day-to-day,” said

To figure out the underlying pressures that drive some birds to leave home for the season, said W. Alice Boyle of the University of Arizona. He examined 379 related species of New World flycatchers and compared their size, food type, habitat, migratory behavior and whether or not they fed in flocks.

To compare the birds, the researchers constructed a “supertree” showing the exact evolutionary relationships among different species.

A computer analysis then determined whether a particular species was migratory because it ran in the "family" or whether something in the bird’s environment was forcing it to leave each season.

Boyle and her colleagues found that food scarcity was the number one issue that predicted a species’ migratory behavior.

“Food availability is the underlying process, not diet and habitat,” Boyle said.

An alternative strategy to migrating that the birds used to deal with food scarcity was to forage in flocks, because a group is more likely to find a new patch of food than alone individual.

Thursday, March 1, 2007

New species of Indonesian sharks and rays

"Indonesia has the most diverse shark and ray fauna and the largest shark and ray fishery in the world, with reported landings of more than 100,000 tons a year,'' said William White, a co-author of the sharks and rays research.

Twenty new species of sharks and rays have been discovered in Indonesia in a five-year survey of catches at local fish markets, Australian researchers said Wednesday.

The survey by the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO), represents the first in-depth look at Indonesia's sharks and rays since Dutch scientist Pieter Bleeker described more than 1,100 fish species from 1842-60.

Researchers said six of their discoveries have been described in peer review journals, including the Bali Catshark and Jimbaran Shovelnose Ray, found only in Bali, and the Hortle's Whipray, found only in West Papua.

From 2001 to 2006, researchers photographed and sampled more than 130 species on 22 survey trips to 11 ports across Indonesia. More than 800 specimens were lodged in reference collections at the Museum Zoologicum Bogoriense at Cibinong, Java, and the Australian National Fish Collection at Hobart.

The survey was part of a broader project working toward improved management of sharks and rays in Indonesia and Australia, researchers said. “Good taxonomic information is critical to managing shark and ray species, which reproduce relatively slowly and are extremely vulnerable to overfishing,'' White said in a statement.