Bats are nature's pest hunter. Every night they fly out of their caves to enjoy millions of insects, including some harmful ones. But habitat（栖息地）loss and climate change, as well as infectious diseases are preventing them from doing their job. A new study adds another item to the list wildfires. But not too many—too few.

In California's Sierra Nevada, bats have adapted to occasional fires. But a century of fire-suppression（抑制）policies has kept some areas unburned for long periods, resulting in thicker forests and undergrowth. "We wanted to see how these changes might be influencing bat biodiversity." says ecologist Zack Steel in University of California, who conducted the research.

Steel and his colleagues tracked bats for over four years at six spots in Sierra Nevada. Three of the areas had been recently hit by wildfires, and three remained unburned.

Seventeen bat species call these forests home. The study revealed that eight of them tended to frequent the unburned areas, whereas 11 used the burned areas（some species visited both）. "We expected to see one group of species benefiting from fire—the more open-habitat-adapted species—and another group to be negatively affected by fire and prefer the unburned areas," Steel says. "But even some of those species were occurring more often in burned areas.”

What is ideal, the researchers write, is a combination of unburned areas and ones burned at different levels of severity. The results were published last December in the journal Scientific Reports.

"When there are changes in habitat after a fire, many species benefit in different ways," says University of Connecticut biologist Andrew Stillman. "On the whole, the community becomes more diverse, and that's a good thing for the landscape.”

Extinguishing wildfires early leads to some species losing out on food and resources. "Fire is a natural part of the ecosystem, and many animals require the disturbance from fire to create the types of habitat that they need," Stillman adds. "It shows another negative consequence of keeping wildfire away from fire-adapted forests in California."

The colorful anemonefish (海葵鱼), also known as clownfish, possesses a cheerful and carefree image among humans. However, their actual behavior might not always align with the family-friendly portrayal seen in a Pixar film. They can aggressively defend their territory against other anemonefish they perceive as threats.

To investigate how these fish identify group members, a team from Japan conducted two experiments with lab-raised common clownfish that had never encountered any other species.

In the first experiment, researchers introduced different species of anemonefish, distinguishable by the number of white bars on their bodies, into a tank in small cases. They observed that the common clownfish were particularly hostile toward members of their own species that displayed three white bars. These fish fought 80 percent of their specific-targeted fish for up to three seconds. In contrast, invaders from other species, like the orange skunk clownfish with no side bars and a white line along its back, were barely attacked. The two-barred Clarke’s clownfish and three-barred saddleback clownfish were “mildly bullied”, according to the team.

During the second experiment, the researchers exposed a colony of clownfish to various plastic discs. The discs were painted with anemonefish coloration and measured the level of aggression towards these artificial models. Similar to reactions to live fish, models with two bars were less frequently attacked, and those without any bars saw the least aggression. According to study co-author and ecologist Kina Hayashi, the findings “suggest that clownfish is capable of counting the number of bars to recognize the species of the invader”.

The team also found that a rigid hierarchy (社会等级) within clownfish colonies determines which specific fish attack the invader. Earlier studies have shown that the social position of the clownfish is determined by very slight differences in size. This study used fish that had not matured and were in a lab setting, but the team still observed the same size-based hierarchy. The largest clownfish led the charge against the invader.

Scientists recently have announced a new primate species-Popa langur, a medium-sized leaf-eating monkey living in central Myanmar.

Popa langur-named for an extinct volcano home to its largest population of about 100 individuals-has been around for at least a million year, according to a study published in Zoological Research.

In fact, the newest monkey species was not found during an expedition or spotted by a research team, but was discovered in the backrooms of the London Natural History Museum. The senior author of the study, Frank Momberg, and his colleagues conducted a genetic analysis of a sample of monkey feces (粪便) collected in the forests of central Myanmar and Compared it with specimens (标本) from Myanmar gathered almost a century ago in the museum, only to find out that the previously unknown langur was still roaming (在……漫步)in the wild.

Scientists set up cameras in the forest hoping to get a glimpse of the creature. In 2018, the monkey was finally filmed, revealing its distinctive coloration.

Although it’s exciting news for scientists to find a new species, after investigation, they found the total number of Popa langur is about 200 to 250, which will likely mean the new species is “critically endangered”. Additional field surveys and protection measures are urgently required to save the langurs from extinction.

The discovery of Popa langur also brings people’s attention to new species identification.

Actually, species are not clearly divided as we learned in school. Scientists define a species by whether the animals are able to produce fertile offspring (后代) together. Another way is to use genetic information, which is mainly used to define a species that is genetically distinguished from another but still shares a clear ancestor.

When scientists announce a newly defined species based on genetic evidence, it usually means they have elevated (提升为) an alrealy defined subspecies to the species level. The Popa langur, for example, was previously classified as a member of a specific group of langur monkeys.

It can be controversial to elevate a subspecies into a new species based on genetic information,like Popa langur. Some scholars dismiss these discoveries. But others think without a unique name and estimated population, these small groups cannot get enough conservation funding and may eventually disappear without anyone knowing it.