Swarm Immunity
Honeybees run vaccination programmes, too. An old saw has it that there is nothing new under the sun.
Being gregarious, honeybees are at constant risk of diseases sweeping through their hives. Most animals which live in crowded conditions have particularly robust immune systems, so it long puzzled entomologists that honeybees do not.
Part of the answer, discovered in 2015, is that queen bees vaccinate their eggs by transferring into them, before they are laid, fragments of proteins from disease-causing pathogens.
To test this idea, he teamed up with a group at the University of Helsinki, in Finland, led by Heli Salmela.
| A．With this modified method, we show variation in honey bee immunity in response to different classes of pathogens. |
| B．Together, they collected about 150 nurse bees and divided them among six queenless mini hives equipped with broods of larvae to look after. |
| C．Indeed, they actually possess fewer immune-related genes than most solitary bees. |
| D．Over the years, scientists have uncovered how insect immunity relates to behavior, mating success, ability to find food, nutrition, energy cost, etc. |
| E．These act as antigens which trigger the development of a protective immune response in the developing young. |
| F．But it may still come as a surprise that human beings are not alone in having invented vaccination. |
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【推荐1】Biologists Slagsvold and Wiebe have spent years studying tits, flycatchers, and other birds that lay their eggs into holes in trees, walls and even human-made boxes. “Holes are rare, so there’s great competition,” Wiebe said. Birds will sometimes get into fights. Even after a bird gets a hole, it has to watch out: There’s always a chance that a passerby tries to possess it. Owners don’t have many options to wait for and stop thieves. Some police their nest’s entrance hole, but preparing for parenthood is hungry work, and eventually the birds have to leave to get food. So Slagsvold and Wiebe started to look for alternative home-defense systems the birds might be using.
They noticed feathers, usually helping animals keep warm, but that doesn’t seem to be how these particular birds are using them. Blue tits, for instance, get feathers on top of the nest, rather than putting them in. Some other birds dump feathers into holes before gathering other materials. “They’re white, and often noticeable,” Wiebe said, “as if the birds want to send a message.”
To find out, they built nest boxes — some feathery, some not — in Europe and America, and recorded how tits, flycatchers and swallows reacted. The birds entered feather-free boxes quickly. But they froze at the sight of white feathers, sometimes hesitating outside for an hour. Black feathers scared them less, perhaps because they were harder to see. The feathers didn’t stop the birds as most eventually went inside. But even a brief delay can make a huge difference, Wiebe said. “Even 20 minutes can give the owner enough time to circle back, and fight off their competitors.”
The birds’ behavior shows their high-risk lifestyle. They have to think twice as the holes may be hiding danger. The feathers represent possible violence, showing a predator might be inside.
The experiment reflects the lies animals tell where nest sites are rare. They build a scene so horrible to discourage nest stealers. Birds are terrified of death. And they can exploit that reality to safeguard what’s theirs.
1. What inspired Slagsvold and Wiebe to seek birds’ other possible ways to protect homes?| A．Birds have to fight to get the limited holes. | B．Birds get tired from watching out in nests. |
| C．Birds face many nest stealers on their own. | D．Birds leave their nests unattended sometimes. |
| A．To show a friendly welcome. | B．To help stealers avoid danger. |
| C．To buy time for the nest owners. | D．To confirm this place is occupied. |
| A．Understandable. | B．Confusing. | C．Possible. | D．Worrying. |
| A．Some birds refuse to build their nests | B．It’s important for birds to have feathers |
| C．High risks of life lead birds to turn to lies | D．Birds create a false scene to protect their nests |
【推荐2】In contrast to the brightly coloured species of birds, most of mammals are browns and greys, but with a small number of exceptions, of which the most famous is the giant panda. We’ve had some initial assumption about why they had their markings, but we need to confirm the reason for its mysterious pattern.
Viewed up close in a zoo, the giant panda is a strikingly notable mix of a white bear with black shoulders and legs, and an extraordinary face with black fur around the eyes and ears. By comparing with other carnivores (食肉动物), we learned that carnivores with white backs are found in snowy environments, and those with dark legs and shoulders are found in shady habitats. This suggested that the fur was an adaptation to be self-protective in different environments.
Nowadays, giant pandas are confined to forests in western China, where they live on their own and there are relatively few predators (捕食者). We are to confirm that the sort of self-protection is effective against giant pandas’ former predators from the days when they ranged right across China into Vietnam.
By comparing the amount of light reflected from the giant panda’s fur with natural objects in the background, it’s clear that their black fur patches (斑纹) match dark shades and tree trunks, whereas their white patches match bright leaves and snow. Also, pale brown, or muddy fur matches the color of the ground. This provides a medium color which bridges the gap between the very dark and very light visual elements in the natural habitat. Besides, a second form of self-protection lies in something termed misorderly colors and patterns-in which highly visible patches break up its outline by mixing with patches in the background.
Giant pandas show this form of defensive outline, especially at longer viewing distances of at least 60 meters away. At these distances, the giant panda becomes hardly identifiable as the black fur patches go with the background, dark rocks and tree trunks.
Although giant pandas in zoos are highly notable to us, it is because we see them up close and surrounded by artificial backgrounds. But when in the wild and at a distance, our research shows that they are beautifully protective to avoid detection.
1. How are giant pandas different from most mammals?| A．They are more brightly colored. |
| B．They are marked with browns and greys. |
| C．They have exceptional colors and patterns. |
| D．Their dark legs match snowy environments. |
| A．Enclosed in. | B．Raised in. | C．Lost in. | D．Trained in. |
| A．To explain the reason for pandas living in the wild. |
| B．To confirm the panda’s color connection to the habitat. |
| C．To compare the differences of pandas’ body parts in color. |
| D．To conclude the relationship between light and pandas’ colors. |
| A．They look darker in the artificial background. |
| B．Their patterns are determined by their whereabouts. |
| C．The effectiveness of defensive colors is related to distance. |
| D．They are more beautifully-colored in the wild than in the zoo. |
【推荐3】ANIMAL BODY LANGUAGE
Human beings are not only ones who communicate.
Elephants also use noises and body language to express themselves. An elephant’s sense of smell is highly developed. An elephant can smell how another elephant is feeling and even tell if it is sick. The elephant’s nose, or trunk, is also used to make noises and to welcome other elephants. Different noises have a variety of meanings they can mean “I am hungry”, “I am angry”, or “Good to see you!”
Dolphins are social animals.
| A．Dogs are human’s loyal friends. |
| B．If you see them doing this, you should not disturb them. |
| C．An elephant’s body language includes ear signals and gestures. |
| D．They live in groups and love showing each other their feelings. |
| E．Dogs use sounds, body movements, and their tails to communicate. |
| F．If an elephant senses its partner is falling sick, it will also make a noise. |
| G．Animals use body language to tell each other how they feel and what they think |
【推荐1】When life gives you lemons, make lemonade, yes, and drink all of them. Then you're ready for an adventure.
Researchers from the University of Sussex in England say they have found for the first time experimental evidence that sour tastes lead to more risk-taking behaviour in a paper published on 7 June, 2019.
In the study, 168 volunteers from the UK and Vietnam were given a 20ml solution representing one of the five main taste groups: bitter, salty, sour, sweet and umami. The tasters then took part in a computerized test that measures risk-taking: they got paid to blow up a digital balloon. The more air in the balloon, the more money they could get; they could cash out whenever they wanted. But if the balloon popped or exploded? Bye bye , potential winnings.
When the researchers studied the performance of the volunteers, they found the people who'd tasted sour were much more likely to keep pumping up the balloon compared with people who'd gotten a taste of the other solutions. On average, sour tasters were 39% more likely to push the balloon to its limits than sweet tasters, 20.50% more than bitter, 16.03% more than salty and 40.29% more than umami.
This finding makes a degree of sense—without taking risks, we don't learn anything new. And it is obvious that people with disorders such as anxiety and depression are unwilling to take risks. So, the researchers argue, if you have these disorders, maybe adding more sour foods into your diet could help keep that aversion in check. Then you'd be more likely to take chances, like talking to a stranger, and that will lead to self-improvement.
1. Where does this passage most probably come from?| A．A travel guide. | B．A novel. |
| C．A magazine. | D．A poster. |
| A．They came from the University of Sussex in England. |
| B．They got one taste drink after they filled up a balloon. |
| C．Those who blew up a digital balloon got more money. |
| D．Sour tasters were likely to push the balloon to its limits. |
| A．are in a negative mood |
| B．like to drink lemonade |
| C．joined in the experiment |
| D．like talking to strangers |
| A．Good Tastes Encourage Adventures. |
| B．Sour Tastes Make You Risk-taking. |
| C．Lemonade Does Good to Health. |
| D．Sour Foods Keep You Happy. |
【推荐2】Every four or five years, vast quantities of warm water build up along the west coast of South America. This phenomenon, El Nino, creates storms that cause destructive floods. The result is costly.
Modern farmers come to terms with El Nino. They use money saved in good years to rebuild in bad ones. But history suggests it need not be like that. In a paper published recently, Ari Caramanica, an archaeologist at University of the Pacific, in Lima, shows how it used to be done. And the answer seems to be, “better”.
Dr Caramanica and her colleagues have been studying the Pampa de Mocan, a coastal desert plain in northern Peru. Pampa de Mocan is not suitable for farming. Its soil contains little organic matter and the annual rainfall in non-Nino years is usually less than two centimeters. Today’s farmers therefore depend on canals to carry water from local rivers to their fields.
It had been assumed that ancient farmers had a similar arrangement — and so they did. But Dr Caramanica also found eight canals that could carry water far beyond the range of modern farms. She thinks that they were intended to guide the floodwaters arriving during Nino years. Around a quarter of the ancient agricultural infrastructure of this area seems to have been built only for managing Nino-generated floodwaters.
Evidence from pollen supports this theory, revealing that Pampa de Mocan produced lots of crops in some years, while remaining nearly barren in others. The team also uncovered two cisterns in the area serviced by the extended canals. These, probably, were used to store extra flood-water.
These findings suggest that, rather than resisting El Nino, early farmers in Pampa de Mocan were ready to make use of it when it arrived. Modern farmers might do well to learn from them.
1. What does the recent study focus on?| A．Living with El Nino. | B．Effects of El Nino. |
| C．Farming on desert. | D．Water shortage in Peru. |
| A．Ancient farmers. | B．Rivers. | C．Farms. | D．Canals. |
| A．Every advantage has its disadvantage. | B．In every difficulty lies an opportunity. |
| C．Sharp tools make good work. | D．It’s never too late to mend. |
| A．Education. | B．Travel. | C．Business. | D．Science. |
【推荐3】A “lost tribe” that reached America from Australia may have been the first Native Americans, according to a new theory.
If proved by DNA evidence, the theory will break long established beliefs about the southerly migration of people who entered America across the Bering Strait, found it empty and occupied it.
On this theory rests the belief of Native Americans to have been the first true Americans. They would be classified to the ranks of escapee, beaten to the New World by Aboriginals (土著人) in boats.
To a European, this may seem like an academic argument, but to Americans it is a philosophical question about identity, Silvia Gonzales, of Liverpool University said.
Her claims are based on skeletons found in the California Peninsula of Mexico that have skulls quite unlike the broad Mongolian features of Native Americans. These narrow-skulled people have more in common with southern Asians, Aboriginal Australians and people of the South Pacific Region.
The bones, stored at the National Museum of Anthropology (人类学) in Mexico City, have been carbon-dated and one is 12,700 years old, which places it several thousand years before the arrival of people from the North. “We think there were several migration waves into the Americas at different times by different human groups,” Dr. Gonzales said. “The timing, route and point of origin of the first colonization of the Americas remains a most contentious topic in human evolution.”
But comparisons based on skull shape are not considered conclusive by anthropologists, so a team of Mexican and British scientists, backed by the Natural Environment Research Council, has also attempted to take out DNA from the bones. Dr. Gonzales declined yesterday to say exactly what the results were, as they need to be checked, but indicated that they were consistent (一致) with an Australian origin.
1. It is generally considered that the first Native Americans came from ________.| A．North Asia | B．Australia |
| C．South Pacific | D．South Asia |
| A．the narrow skull shape |
| B．different features of Aboriginal Australians |
| C．the broad skull shape |
| D．the same features of Native Americans |
| A．likely to cause great interest |
| B．difficult to solve |
| C．well-known to all |
| D．likely to cause argument |
| A．Research on skulls can draw an exact conclusion. |
| B．DNA tests have proved the fact that the first Native Americans came from Australian. |
| C．Scientists are still not sure about the origin of the Native Americans. |
| D．People began to enter America across the Bering Strait about 12,700 years ago. |
