The science of why insects gather around lights at night has never been nailed down. Popular theories propose that moths and other insects navigate (导航) by the moon and mistake lamps for moonlight, or that the insects fly towards light to escape coming danger. Now researchers believe they have a more convincing answer: contrary to current theories, insects are not attracted to light from far away, but become trapped if they fly close to an artificial light source. 

According to Dr Sam Fabian, study co-author and Imperial College London entomologist, moths and many other insects that fly at night evolved to tilt (倾斜) their backs to wherever s brightest. For hundreds of millions of years, this was the sky rather than the ground. The rick told insects which way was up and ensured they flew level. But then came artificial lighting. Moths found themselves tilting their backs to street lamps. This caused them to circle around the lamps endlessly the insets trapped by their evolution. 

Fabian and his colleagues filmed insect fight paths around lights in the lab. The videos reveal that time and again, moths and dragonflies turned their backs to artificial lights. which appeared to greatly change their fight paths. " If the light is above them, they might start orbiting it, but if it' s behind them, they start tilting backwards and end up flying in circles or diving toward the ground. 

Researchers have long waned that light pollution  is a big driving force in the dramatic decline in insect populations. Moths and other insects that become tapped around lamps, become easily caught by bats. The artificial lighting can also fool them into thinking it is daytime, causing them to bed down and skip a night' s feeding. 

There are, Fabian believes, helpful lessons from the research. " What this tells us is that the direction of artificial light matters. Could we change lighting environments to not trap insects? For we're facing a massive decline in insects around world, and artificial light at night is one of the factors that could potentially be leading to this decline. " Fabian said. 

If you love chocolate，maybe you have eaten a bar of Cadbury's Bournville chocolate. But Bournville isn't just the name of an English chocolate bar. It's the name of a village which was built especially for workers at the Cadbury's chocolate factory.

George and Richard Cadbury took over the chocolate business from their father in 1861. A few years later, they moved the factory out of the centre of Birmingham, a city in the middle of England, to an area close to the railways and canals so that they could receive milk deliveries easily and send the finished products to stores across the country. More importantly, here, the air was much cleaner than in the city, and the Cadbury brothers thought it would be a much healthier place for their employees to work.

They named the site Bournville after a local river called “The Bourn” and “Ville”，the French word for town, was used because at the time, people thought French chocolate was the highest quality. The new factory opened in 1879. Close to it, they built a village where the factory workers could live. The Cadbury brothers thought their workers deserved to live and work in good conditions. In the factory, workers were given a fair wage, a pension and access to medical treatment. The village provided everything that workers needed including a shop，a school and a community centre where evening classes were held to train young members of the workforce.

The Cadbury brothers were among the first business owners to make sure that their workers had good standards of living. Soon, other British factory owners were copying their ideas by providing homes and communities for their workers designed with convenience and health in mind.

Today, over 25,000 people live in Bournville village. Over a hundred years since the first house here was built, the aims of its founders have still been carried out.

Last night my husband and I were taking a post-dinner walk in a nearby parking lot, where we saw a man bending over on the ground, crushing something with a rock. He was completely focused on his task and didn't look up at anyone passing by. We kept noticing him as we hung around the parking lot and guessed what he could be doing. I thought he was crushing stones to make sand, but why would he do that?

Finally we decided to go up and speak to him. He was crushing pieces of leftover bread that he collected from all his roommates to feed the birds that come there early morning. The large pieces of Indian bread would be difficult for the birds to eat, so he crushes them into a fine powder.

He's been doing this every night, by himself, for the last 3~4 years. What moved us more was that he was surprised when we were even taking an interest in this, since for him it wasn't a big deal. Every night, after reaching his bachelor accommodation from his job as a tailor, he goes around the village collecting leftover bread from all his housemates. He then eats a quick meal and comes here, and spends the next 1~2 hours, thoroughly crushing each piece and makes a neat pile for the birds, which will be gone by next evening.

When we asked him what motivates him to do this simple, small but committed act of service, he shrugged his shoulders and said, "It's just something small I do; so that the leftover bread doesn't go into the trash and the birds get food." We shared his story with the hope that it reminds us to be mindful of leftovers too and perhaps it might inspire someone to start something similar in their own area.