【推荐1】Mutualism—win-win ecological partnerships perfected over evolutionary time-lengths—is a less-known ecological relationship that is also weak and easily hurt by the effect of a rapidly changing planet.

Bees and flowers are typical examples of mutualism. Some bee tongues are perfectly evolved to tap into certain flowers. By specializing in those plants, the longer-tongued bees reduce competition with insects that can't access those sweet foods.

That mutualistic relationship, however, has been impacted in at least one population of bees and flowers. As certain flowers in Colorado have become rarer due to warming temperatures, the tongues of the bumblebees（大黄蜂）that historically fed on them have become shorter.

Like many of their relatives, bumblebees are on the decline. To find out what's going on, a team of researchers headed to Colorado. The researchers examined bumblebee samples collected on three mountains from 1966 to 1980 and also gathered a fresh set, which they collected in the same places from 2012 to 2014. They performed the task of measuring all the historic and recently caught bees' tongues.

As the team reports in Science, both of the species tongues have declined in length over time. The team found a nearly 25-percent decrease in tongue length between the bees collected decades ago and those living in the same region today.

Next they turned to the flowers. Looking at contemporary and historic botanical data, the scientists confirmed that the number of flowers with short tubes did not increase in large quantities. They found that in response to warmer temperatures, flowers have been moving up the mountains and becoming rarer at lower altitudes. This altitude-climbing effect has ultimately resulted in an approximate loss of millions of flowers.

The findings paint a telling picture: hotter summers caused bumblebees' choice flower species to disappear, forcing them to evolve shorter tongues to tap into the remaining food sources. Then, competition with generalist species, more time and energy needed and a forced reliance on alternative sources all likely contributed to the bees' overall decline.

【推荐1】Flowing through winding streets of London were smells, so common during the Great Plague (瘟疫) of the 17th century that they almost meant the plague itself, historians said. For hundreds of years, people believed that disease was spread not through tiny drops or insect bites, but through taking in unpleasant smells. To purify the air around them, they would burn rosemary and hot tar.

Now, as the world faces another widespread outbreak, a team of historians and scientists from six European countries is seeking to identify and categorize the most common smells of daily life across Europe from the 16th century to the early 20th century and to study what changes in smells over time reveal about society.

The project will search through more than 250,000 images and thousands of texts, including medical textbooks, novels and magazines in seven languages. Researchers will use machine learning and AI to analyze references to smells. Once they are cataloged, researchers, working with chemists and perfumers, will re-create roughly 120 smells with the hope that museums will incorporate some of them into exhibits to make visits more immersive (沉浸式的) or memorable to museum-goers. The use of smells in exhibits could also make museums more accessible for blind people and those with limited sight, historians said.

“With smell, you can open up questions about national culture, global culture and differences between communities,” said Dr. Inger Leemans, a professor of cultural history at Vrije University Amsterdam. He said that introducing smells into museums or classrooms leads people to open up in discussions in ways they do not always do when discussing other issiues of national identity. “It is such an open topic and what we want to do is think about how we can bring history to the nose.”

【推荐3】Earlier studies suggested that fatigue from virtual meetings stems from mental overload, but new research from Aalto University shows that sleepiness during virtual meetings might actually be a result of mental underload and boredom.   

“I expected to find that people get stressed in remote meetings. But the result was the opposite —— especially those who were not engaged in their work quickly became drowsy during remote meetings, “says Assistant Professor Niina Nurmi, who led the study.

The researchers measured heart rate variability during virtual meetings and face-to-face meetings,examining different types of fatigue experiences among 44 knowledge workers across nearly 400 meetings. The team at Aalto collaborated with researchers at the Finnish Institute of Occupational Health,where stress and recovery are studied using heart rate monitors. “We shadowed each subject for two workdays, recording all events with time stamps, to find out the sources of human physiological responses,”Nurmi says.

The study also included a questionnaire to identify people’s general attitude and work engagement. ”The format of a meeting had little effect on people who were highly engaged and enthusiastic about their work. They were able to stay active even during virtual meetings. On the other hand, workers whose work engagement was low and who were not very enthusiastic about their work found virtual meetings very tiring. “

It’s easier to maintain focus in face-to-face meetings than virtual ones, as the latter have limited cognitive cues and sensory input. “Especially when cameras are off, the participant is left under-stimulated and may start to compensate by multitasking,” Nurmi explains. Although an appropriate level of stimulation is generally beneficial for the brain, multitasking during virtual meetings is problematic. Only highly automated tasks, such as walking, can be properly carried out during a virtual meeting.   

“Walking and other automated activities can boost your energy levels and help you to concentrate on the meeting. But if you’re trying to focus on two things that require cognitive attention simultaneously, you can’t hear if something important is happening in the meeting. Alternatively, you have to constantly switch between tasks. It’s really taxing for the brain,”Nurmi says.

【推荐3】While environmental assessments of new roads focus on the danger of habitat destruction, or bats colliding (碰撞) with traffic, the first ever controlled field experiment to investigate the impact of vehicle noise suggests the thunder of road traffic is likely to drive away bats and cause bat activity to decrease by two-thirds.

Researchers played noise recorded from the A38 dual carriage way in demon, with a “dusk average” of 26 vehicle passing per minute, in locations where different bat species flew and fed. The wild bats, including pipistrelle species, were monitored with bat detectors (探测器) placed beside, and 20 metres away, from the recorded noise.

Ultrasonic (超音速) sounds from vehicle were found to block some bat species' high-frequency echo - location calls, which they use to find insect prey (捕获物) such as moths. But more significant was that most bat species sought to avoid audible (听得见的) traffic noise.

“Just like us, bats are likely to find audible road noise an irritation, something they would prefer to avoid rather than it jamming their echo-location,” said Fiona Matt hews, lead author of the paper in Environmental Pollution.

Matthews said the effect of ordinary traffic noise on bats meant that the negative impact of new roads on bat populations was likely to be more far-reaching than realized.

She said: “This is important, as it means we could expect to see negative effects continue at a considerable distance from the road. We know that lower frequency road noise travels well beyond 50 metres — the scale at which ecological impact assessments are conducted.”

Dr. Henry Schofield, from Vincent Wildlife Trust, which jointly funded the research, said: “We have raised people’s awareness that bat species face barriers in the landscape that impede (妨碍) their ability to access suitable feeding areas and reduce their chances of survival. Along with habitat destruction and artificial lighting at night, this research has added road noise to the list of anthropogenic (人为的) factors reducing habitat quality for these protected species.”