In nature, smaller animals often “take a ride” on larger ones to save energy on long-distance movements. In paper published in the journal Current Biology, researchers show how fine Caenorhabditis worms can use electric fields to “jump” across Petri plates or onto insects, allowing them to go through the air and attach themselves, for example, onto naturally charged bumblebees (大黄蜂).

“Pollinators(传粉昆虫), such as insects and hummingbirds, are known to be electrically charged, and it is believed that pollen (花粉) is attracted by the electric field formed by the pollinator and the plant,” says Takuma Sugi, a co-senior author on the study. “However, it was not completely clear whether electric fields are used for communications between different land animals.”

The researchers first began studying this project when they noticed that the worms they developed often ended up on the lids of Petri dishes. When the team attached a camera to observe this behaviour, they found that it was not just because worms were climbing up the walls of the dish. Instead, they were jumping from the floor of the plate to the top.

Next, the researchers rubbed flower pollen on a bumblebee. Once close to these bees, worms stood on their tails, then jumped aboard. Some worms even piled on top of each other and jumped in a single post, moving 80 worms at once across the gap.

“Worms stand on their tail to make it easier for themselves to attach to other passing objects,” Sugi says. “In a post, one worm lifts more worms, and this worm takes off to move across the electric field while carrying all the post worms.

Researchers observed jumping in other worm species closely related to C. elegans, and they noted that mutants (突变体) who are unable to sense electric fields jump less than their normal counterparts. However, more work is needed to determine exactly what genes join in making these jumps and whether other microorganisms like bacteria can use electricity to jump as well.

Finding fish is going to get harder as climate change continues to heat the world’s oceans. A new study finds that warming seas over the past 80 years have reduced the sustainable (可持续) catch of 124 species of fish.

Sustainable catch refers to the amount that can be harvested without doing long-term damage to the health of populations of some species.

Overfishing has made that decrease worse, researchers say. Overfishing refers to catching so many fish that the size of the population falls. In some parts of the world, such as the heavily fished Sea of Japan, the decrease is as high as 35 percent. That’s a loss of more than one in every three fish.

Researchers examined changes in 235 populations of fish between 1930 and 2010. Those fish populations were in 38 ocean regions. Temperature changes are different from one ocean site to another. But on average (平均) over that time, Earth’s sea-surface temperatures have risen by about 0.5℃.

On average, that warming has caused the sustainable catch to drop 4.1 percent, the study found. About 8 percent of the fish populations the team studied saw losses as a result of the ocean warming. About 4 percent of the population increased. That’s because certain species have thrived in warmer waters. One example is the black sea bass (鲈鱼). It lives along the northeastern U. S. coast. But as warming continues, even these fish will reach their limit, says Christopher Free. He works at the University of California, Santa Barbara. He led the work while he was at Rutgers University in New Brunswick, N. J. His team shared its findings March 1 in Science.

Honey(蜂蜜)from the African forest is not only a kind of natural sugar, it is also delicious. Most people, and many animals, like eating it. However, the only way for them to get that honey is to find a wild bees’ nest(巢)and take the honey from it. Often, these nests are high up in trees, and it is difficult to find them. In parts of Africa, though, people and animals unexpected helper一a little bird called a honey guide.

The honey guide does not actually like honey, but it does like the wax (蜂蜡) in the beehives (蜂)finally arrive at the nest, the followers reaches in to get at the delicious honey as the bird patiently waits and watches. Some of the honey, and the wax, always falls to the ground, and this is when the honey guide takes its share.

Scientists do not know why the honey guide likes eating the wax, but it is very determined in its efforts to get it. The birds seem to be able to smell wax from a long distance away. They will quickly arrive whenever a beekeeper is taking honey from his beehives, and will even enter churches when beeswax candles are being lit.