【推荐1】Like human armies, army ants smoothed out anything in their path. They make a habit of finding foods, often much larger than themselves, breaking them into pieces and dragging the pieces back to their camps. But they do not eat them out, with their army bases full of rubbish. But little is known about which kind of animals feed on army ant leavings. Christoph von Beeren at the Technical University of Darmstadt and Daniel Kronauer at the Rockefeller University in New York went to the rainforests of Costa Rica to find out. They found a whole ecosystem (生态系统) depends on the left foods to survive.

Watching little insects (昆虫) in a rainforest is much tougher—one reason why these cleaners had not been examined before. But the researchers hoped modern DNA analysis techniques might make the job easier. Working with a team of coworkers, they followed ants back to their camps, finding 34 places in total.

The researchers collected all the insects at each place and brought them back to laboratory. In total, they collected 8, 364 adult beetles (甲壳虫), 511 beetle baby and 24beetle eggs. Those were spread across 91 species, several of which were new to science. Far beyond what anyone had expected, these figures suggest that the left foods are not fast-food restaurants but homes, where the beetles live from birth to death.

How these species manage to avoid being eaten by their army-ant hosts is still a mystery. Dr von Beeren guessed that it partly depends on the fact that ants need them to keep their camps clean or partly depends on the fact that many species of beetles are able to produce chemicals that smell bad to ants.

The research only has shown a little of what is going on in the rubbish. Besides beetles, there were other kinds of insects that the team simply did not have time to study and they were of equal importance to their study according to Dr Daniel Kronauer.

【推荐2】North America's hoary bats could decline massively unless efforts are made to reduce deaths at wind farms, a new study reports. It is estimated that without effective conservation efforts, hoary bat populations could drop by 50% by 2028.

Hoary bats are comparatively large bats, whose weight is between 20—35 grams. They have dark fur dusted with white, which is how they got their name. Hoary bats undergo seasonal migration, moving from summer ranges across most of North America to southern and coastal winter habitats. Hoary bats will also hibernate for short periods of time. Hoary bats in North America provide vital ecosystem services such as insect pest consumption. The economic value of insectivorous bats to U.S. agricultural industry has been estimated in the billions annually.

“Researchers and conservation biologists have been concerned about the number of bats killed at wind farms for more than a decade, but this research emphasizes how urgently we need to act to carry out known solutions” says study co-author Winifred Frick, chief scientist for Bat Conservation International.

For their research, Frick and colleagues created models of species population growth and mortality. They considered two wind energy build-out plans―high and low—which looked at the expected growth of the wind energy sector in the United States and Canada through 2050. The report focused on determining how wind energy expansion might affect hoary bat mortality and what industry solutions could be put in place to help.

“The good news is we already know how to reduce bat deaths. The best evidence so far suggests that wind turbine limit below five meters per second could reduce hoary bat deaths nearly in half. By working together with industry partners, we can have sustainable wind energy while protecting biodiversity.” Frick told Treehugger.

【推荐3】The winter migration (迁徙) season has arrived. With the cold wave heading down south, migratory birds from faraway places such as Siberia have begun to arrive at Dongting Lake, central China for the winter.

Dongting Lake in central China’s Hunan Province is the country’s second-largest freshwater lake. When the temperature rises after a short cold time, locals call the 10th lunar month “Indian summer.” During this time, the lake’s water level drops and sedges (莎草) grow, allowing wintering birds to plentiful food.

Song Yucheng, deputy chief engineer of East Dongting Lake National Nature Reserve, is proud of their protection work. According to him, the Eurasian spoonbills are the first to arrive at the heart of East Dongting Lake National Nature Reserve. They line up and use sideways sweeps of their beaks to filter (过滤) out tiny fish and shrimp. When they fly to another spot looking for food, people can only see the vast expanse of a white sky.

“Now the weather is also very good, the sky is very clear, with green grass, clear water and white spoonbills wandering for hunting. It’s a beautiful picture of nature,” said Song.   

For the villagers living in the East Dongting Lake National Nature Reserve, their farm fields are still full of busy and active fellows after harvest because there are about 100 swans settled down there. To provide these birds with an quiet and safe environment, the local government has stopped the vehicles and visitors from entering the area.

“Firecrackers are not allowed, and loud noises are also not allowed in the surrounding area,” said Long Yong, a villager from the Hehua Village, citing the local government.

【推荐3】My love for animals began through watching wildlife documentaries when I was a kid. I went on to study Environmental Science at university, and became interested in marine (海洋的) biology when I did my master's degree. That's when I realised that there was a possibility to do more for Hong Kong.

In Hong Kong, many people would associate marine life only with seafood, and few people would consider it as a part of nature to be appreciated. Although our marine life is highly diverse, our waters have been overfished for more than 40 years. Records show that, decades ago, Hong Kong had such high production of seafood that it supported about 90% of the local demand. Today, at least 90% of the seafood we eat has to be imported to meet local demand, as our waters are so overfished that they can no longer support the local appetite.

Despite this shift, we are still a city in love with seafood-according to the Food and Agriculture Organization of the United Nations, Hong Konng has the second highest annual seafood consumption per capita (人均) in Asia-but consumers are barely aware of where their seafood comes from and which species are threatened.

There is a lot of room for improvement in Hong Kong. Improving local fishery management policies and increasing the coverage of Marine Protected Areas, as well as conducting the relevant research to inform decisions, could move the city towards greater sustainability in this area. And consumers should avoid eating seafood that is on the threatened species list. As a general rule of thumb, if people are not sure what the species is, they should choose something else that they are more familiar with.

With the marine ecosystem already weak and easily destroyed, the greatest threat is continued ignorance and inaction. It is time for us to show that we can also be a part of the solution. If each person plays their part - even for just one meal a day-Hong Kong would already be on its way to making considerable progress towards sustainable seafood consumption.

【推荐2】Comparatively few fresh-water species of fishes are limited in their distribution to a single river system, yet not many are found on both sides of a high mountain ridge, such as the Rocky Mountains in North America. That is to say, the fishes of the Mississippi Valley are generally different from those of the Pacific slope.

While it is a well-known fact that the fish life in no two river systems, even though they empty into the sea on the same side of a divide, is exactly identical, such streams do have many species in common. The principal rivers of the Atlantic slope of the United States, for example, contain several species common to all of them, including the bullhead catfish, the bluegill sunfish, and the large mouth bass. None of these species can endure salt water, so they cannot move from one river system to another. On the other hand, the more northern streams contain species not found in the southern ones, and vice versa. The common pike, for example, is found in the Atlantic streams from Maryland northward, and the brook trout and yellow perch occur only in the streams from North Carolina southward.

How the present distribution came about must remain a matter of quest. It is quite probable that some of the streams, including those on opposite sides of a divide, may have been connected at one time. Again, streams may be entirely separate during normal weather, but an exceptionally heavy rainfall or the sudden melting of snow in the uplands sometimes causes floods which may form a temporary connection between them, providing a passageway for fishes. It is also possible that water birds may accidentally carry fish or spawn(卵)   from one stream to another, or that man may be instrumental in such a transfer.

【推荐3】“Our temperature’s not what people think it is,” said Julie Parsonnet, MD, professor of medicine and of health research and policy in Stanford. “or our common sense that our normal temperature is 37 ℃ or 98.6 F, is wrong.”

That standard of 37℃was made famous by German doctor Carl Reinhold August Wunderlich in a book in 1868. Modern studies, however, have called that number into question, suggesting that it’s too high.

In a latest study published in eLife, Parsonnet and her colleagues explore body temperature trends and conclude that temperature changes since the time of Wunderlich reflect a true historical pattern, rather than measurement errors or biases (偏见). The researchers propose that the decrease in body temperature is the result of changes in our environment over the past 200 years, which have in turn driven physiological changes. 

The researchers analyzed temperatures from three officially-recorded datasets covering different historical periods, using the 677,423 temperature measurements from these datasets to develop a linear model (线性模型) containing the temperatures over time. They determined that the body temperature of men born in the early to mid-1990s is on average 1.06 F lower than that of men born in the early 1800s. Similarly, they determined that the body temperature of women born in the early to mid-1990s is on average 0.58 F lower than that of women born in the 1890s. These calculations match a decrease in body temperature of 0.05 F every 10 years.

The decrease in average body temperature in the US could be explained by a reduction in the amount of energy being used. The authors believe this trend may be due to a population-wide decrease in inflammation (炎症): “Inflammation produces all sorts of proteins and cytokines that speed up your metabolism (新陈代谢) and raise your temperature,” Parsonnet said. Public health has improved sharply in the past 200 years due to advances in medical treatments, more convenient environment, greater availability of food and improved living standards. The authors also argue that comfortable lives at constant surrounding temperature contribute to a lower metabolic rate. Homes in the 19th century had irregular heating and no cooling; today, central heating and air conditioning are commonplace. A more constant environment removes a need to expend energy to keep a constant body temperature.