【推荐1】A century ago, millions of Quino checkerspot butterflies flew above Southern California. Each about the size of a paperclip, the Quinos hatched in great numbers each spring.

Toward the end of the twentieth century, however, the development of farms and cities dramatically reduced the butterfly’s habitat. By 1997, the population of the Quinos had declined to a tiny amount of its historical numbers.

The Quino’s situation continued to worsen. Wildfires burned much of its habitat, and temperatures were getting warmer and drier, making the environment more difficult to the butterfly’s host plant called the dwarf plantain.

Scientists knew that Quino caterpillars relied on the dwarf plantain as a food source. Each spring, the adult female butterflies laid eggs on dwarf plantains. When the caterpillars hatched, they fed on the plantain leaves. However, in the hot, dry summer, the plantains died off. The caterpillars responded by entering a state called diapause. Then, when normal winter rains came and the plantains’ flowers came out again, the caterpillars came back to life and started eating. Once they’d grown large enough, the caterpillars formed pupae and emerged as adult butterflies. This strategy worked well in most years, but as average temperatures rose and rainfall decreased, the caterpillars weren’t getting sufficient food, and fewer developed into butterflies.

Because the area where they lived was surrounded by developed cities and desert landscapes, the Quinos had limited options. They took off anyway, flying eastward into the hills. They landed in mountainous open spaces east of Los Angeles and San Diego. They found no dwarf plantains there. The females began laying their eggs on the leaves of other plants, primarily the Collinsia concolor. These plants remained green longer into the summer months. When the caterpillars Quinos survived, and their numbers grew in their new home.

Scientists were surprised when they began encounter innumerous Qunios in the eastern hills. They were cheered to learn that these small insects had adapted to changing conditions. The Quinos demonstrated the toughness needed to survive by finding not only a new habitat, but a new food source, too.

Meanwhile, scientists had been raising Quino caterpillars in a lab and released hundreds of caterpillars into protected areas around San Diego. Between the efforts of scientists and the butterflies’ own actions, more of those colorfully checkered wings may soon be seen fluttering above the Southern California skies.

【推荐2】It’s peak cold and flu season, which means taking a lot of preventative measures. Frequent hand-washing is a must, as is avoiding co-workers or friends who are sick. But we humans are not the only animals that change behaviors to keep diseases at bay. So do ants.

“So there are the foragers (工蚁) and the nurses — it’s two different groups of work,” said Natha of the University of Lausanne. She and her colleagues observed ants to see their reaction to the presence of a disease.

“The nurses being made of young workers typically, stay inside the nest and take care of the eggs. And the foragers are all the workers spending most of time at outside of the nest to collect food and defend the territory.”

Forager ants are at greater risk of getting exposed to diseases because they leave the safety of the nest. So the researchers sprayed a common virus on a small group of forager ants and then followed their movements to see the way other ants reacted.

“We marked all ants in the colony with individual labels, which carries these two-dimensional bar code marks like QR code which is automatically detected and recorded using a tracking system.”

After the infection, the nurse and forager ants stayed within their working places and interacted less outside of their work group. The researchers also saw that forager ants spent more time outside of the nest. “They increase that amount by 15 percent, so by quite a large amount.”

Isolating behavior stops the spread of the virus. “Something that’s quite interesting in these ants that’s been shown by the study is that in their ability to avoid infecting other members of the community, ants may be more advanced than we are,” Natha said.

【推荐3】Mosquitoes see red when they look at your skin, and that brings them in for a bite, according to new research showing that these insects find certain colors more attractive.

The findings mean that what you wear can reduce your chances of being bitten, but there’s little you can do in terms of your skin. That’s because everyone’s skin gives off a strong red-orange signal that’s highly attractive to mosquitoes.

“I used to say there are three major signals that attract mosquitoes: your breath, your sweat and the temperature of your skin,” said senior study author Jeffrey Riffell, a professor of biology at the University of Washington in Seattle. “In this study, we found a fourth signal: the color red, which can be found not only on your clothes, but also in everyone’s skin. The shade of your skin doesn’t matter, we’ re all giving off a strong red signal.”

Researchers found that when a common species of mosquito called Aedes aegypti detects carbon dioxide (CO₂) from our breath, it then looks for specific colors-including red, orange and black — to find its meal of blood. But it ignores colors such as green, purple, blue and white.

“Mosquitoes appear to use smell to help them distinguish what is nearby, like a host to bite,” Riffell said. “When they detect specific compounds, like CO₂ from our breath, that smell stimulates the eyes to scan for specific colors and other visual patterns, which are associated with a potential host, and then they head to them.”

That process is similar to when a person smells something good. “Imagine you’ re on a sidewalk and you smell pies,” Riffell said. “That’s probably a sign that there’s a bakery nearby, and you might start looking around for it. Here, we started to learn what visual elements mosquitoes are looking for after smelling their own version of a bakery.”

Knowing which colors do or don’t tempt mosquitoes may lead to better repellents (驱虫剂), traps and other methods to prevent mosquitoes.