A herd of 15 Asian elephants has been making its way North across China since March 2020, and nobody is quite sure why.

The herd has covered more than 500 kilometers since they wandered out of their home in the Xishuangbanna National Nature Reserve, located in southwestern China along its border with Laos and Myanmar. Authorities in China have tried to keep the animals away from populated areas with piles of fruit and vegetables and physical barriers. The herd was spotted last week on the outskirts (郊区) of Kunming.

“One potential explanation for the elephant migration is overcrowding in the nature reserve these animals once called home,” says George, an elephant specialist at Colorado State University. Asian elephants are endangered, only around 300 surviving in China, but the population living in the reserves of the Xishuangbanna region has been growing in recent years. George says this wayward (任性的) group might have set out to find a new home with less competition for resources.

“We’ve seen elephants expanding their range for decades now, as their populations increase, and they search for more food for the growing herd,” says Becky Chen, a conservation scientist at the Zoological Society of London who has studied elephant-human interactions. Other experts wonder if this is an example of a herd being misled by an inexperienced leader, or if the decision to roam was an almost random choice.

Authorities have instructed residents along the route to stay inside if the elephants are nearby and avoid disturbing the herd. If the animals can’t be turned back to their former forested home, scientists and land managers may need to make provisions (准备) for the elephants to live permanently in Kunming.

Chen says she hopes the situation will raise awareness of human-elephant conflict and elephant conservation. “What we have to learn is not how to solve the problem, but how to increase tolerance,” she says. “How can we use this event to let everybody pay attention to coexistence between people and animals?”

Every year migratory(迁徙的) bats travel from Mexico to Bracken Cave, where they spend the summer consuming insects that would otherwise hungrily eat common food crops. But the bats have been showing up far earlier than they did two decades ago.

In a study, scientists at Rothamsted Research, an agricultural laboratory in England, used radar data from 160 U.S. weather stations to analyze activity in the Texas bat colony from 1995 through 2017. They discovered the creatures were leaving their winter quarters in Mexico earlier and reproducing sooner. They were also astonished to find increasing numbers of bats overwintering(过冬) at Bracken Cave instead of heading back to their cold weather quarters in Mexico. Overwintering is a sign that warmer temperatures change the bats’ annual rhythms, Rothamsted biologist Phillip Stepanian says.

A separate study of migratory bats in Indiana, published last year, found that temperature variations affected arrival and departure times—likewise hinting at the potential influence of climate change. Joy O’Keefe, a biology professor at Indiana State University and co-author of that study, says early arrival at their summer habitats(栖息地) could expose these bats to cold snaps(寒流), and they could freeze to death.

Joy O’Keefe and her colleagues also found that changing bat migration times can also clash with rainfall patterns. Many insects that bats eat breed in seasonal lakes and puddles. If the bats arrive too early to benefit from summer rainfall and the resulting abundance of insects, they may struggle to feed their pups(幼崽) or skip reproduction altogether, O’Keefe says. She fears this shift could cause Midwestern bats to decrease toward extinction, which would be bad news for humans. “Declines in bat populations could have severe effects for crop success,” she says, adding that bats also “control significant disease vectors, such as mosquitoes.”

However, scientists are not certain that climate change alone is causing the Bracken Cave bat colony to migrate earlier. They have found a direct link between seasonal temperatures and bird migration, but bats are also influenced by factors such as changes in wind speed and direction. And there are other complications. “Bats are mysterious little animals that move mostly at night and are difficult to observe and track,” Stepanian says. “We have this conceptual picture of what might be happening, but really tying it to the cause is the next step.”

We all love butterflies. Their beautiful wings attract us, and their presence lights up our garden. Well, that’s our view of butterflies, but have you ever wondered what plants think of them?

The butterflies’ eggs lie on the underside of the leaves. The eggs themselves don’t damage plants. However, upon coming into contact with the eggs, the plants become oversensitive. It means that once a plant recognizes a pest, it will cause death in the contacted plant part. When these dead leaves or partial leaf parts break away from the plant, the eggs on them fall off. Along with the hypersensitivity response, plants also produce something special, which can attract animals to cat the eggs, thus preventing damage in the future.

After the baby butterflies come out of their eggs, the caterpillar (毛虫) stage begins. Most caterpillars feed on the leaves of the plants, damaging some of the plants in your own garden. Incredibly, they are major plant pests that bring about major losses to farmers. The next stage is pupa (蛹). The caterpillars begin their change into an adult. They don’t depend on the energy that the leaves provide. Finally, they become adult butterflies that have wings and move from one plant to the other. They feed on the sweet liquid produced by flowers.

While on their search for food, the butterflies carry pollen (花粉) on their body. They are key pollinators that place pollen from one flower to another in ecosystem. Plants that have flowers will create some special features to draw these pollinators’ attention. Certain plants have flowers giving off smells that can charm butterflies when they are looking for a mate. Some plants even have flat flowers to assist butterflies when landing.

Butterflies aid in pollination during their final adult stage. Thus, they change into beneficial insects to plants. This change makes butterflies an important friend of plants, despite being a hated enemy in previous life cycle stages!