Human beings are not alone in having invented vaccination, while honeybees got there first and they can run what look like vaccination programmes, which has been confirmed by Gyan Harwood of the University of Illinois, Urbana-Champaign.

Queen bees vaccinate their eggs before they are laid. But the question is how the queen receives her antigen supply, for she lives purely on royal jelly, a substance secreted by nurse bees when they are in the life stage of feeding the young. Dr Harwood wondered if the nurses combined the royal jelly they produced with pieces from pathogens they had consumed while eating something brought in from outside.

To test this idea, they collected about 150 nurse bees and divided them among six queenless mini hives equipped with the young to look after. They fed the nurses on sugar-water, and for three of the hives they added Paenibacillus larvae, a bacterium causing a disease, to sugar-water.

Dr Harwood and Dr Salmela labeled the bacteria with a certain dye, to make them easy to track. And, sure enough, microscope confirmed that Paenibacillus larvae were getting into royal jelly secreted by those bees which had been fed with the sugar-water. Moreover, examination of this royal jelly revealed higher levels of defensive substance, compared with royal jelly from bees that had not been mixed with Paenibacillus larvae. This substance is thought to help bee immune systems fight against bacterial infections.

All told, these findings suggest that nurse bees are indeed, via their royal jelly, passing antigens on to the queen, then into eggs. They also mean, because the young receive royal jelly for the first few days after they hatch, the nurses are giving the young the second antigens. Each young bee is therefore being vaccinated twice.

The image was shocking, and the response was entirely predictable. The photo of a polar bear lying lifeless on a beach—blood matting the fur of its neck, with one huge paw folded under its body—received immediate criticism globally. On the shore, in the background, stand three guards, talking to each other. One of them has a rifle hanging casually on his shoulder. The feeling was that of complete disregard for the bear and the environment in which it lived. The reality, however, is considerably more complex.

This powerful image has thrown into question the motivation for this kind of tourism, or ecotourism. Should we be in these environments at all? Are there regions in the world where nature should be left completely untouched? Does our proximity (靠近) to large animals in the wild, frequently fueled by a desire for sensational images, lead to such animals becoming accustomed to human contact? If that is the case, surely the losing side will end up paying the ultimate price for such proximity.

Before answering these questions, we should first consider the incident that has caught global attention. For me, this has struck home. I have recently returned from a trip to Svalbard, and indeed stood two weeks ago on the very beach where the bear was shot. The bear’s death should never have happened. Was the beach examined from the ship offshore beforehand? Were the clients themselves closely supervised to prevent one becoming isolated? Was there access to flares to scare off a bear that appeared suddenly? These are standard measures for any respected operator. The incident is probably the result of a terrible systemic failure.

Nevertheless, the incident should not deny the value of ecotourism. In its best form, this kind of travel has very little impact, or indeed has a positive effect, on the environment where it takes place. This can be by making financial donations to conservation groups, providing income to local communities, or ensuring protection of certain areas or animals. In Svalbard, visitors become ambassadors for the endangered polar bears, increasing awareness of the fact that the far greater danger facing them is sea-ice melt in the Arctic Ocean.

Ecotourism is an expanding market that brings benefits as well as challenges to the regions around the world in which it operates. Simply closing off these regions is not the answer. The key is responsible engagement and further research before you book that trip. When ecotourism is conducted correctly, the benefits can be direct, immediate, positive and long-lasting.

As COVID-19 spreads throughout China and the rest of the world, an important question has yet to be answered: where did the virus come from? The latest study indicated that pangolins(穿山甲)may be an intermediate host of the virus, according to Xinhua. However, bats are suspected to be the original cause.

“We don’t know the source yet, but there’s pretty strong evidence that this is a bat origin coronavirus,” said Peter Dazsak, president of EcoHealth Alliance, an environmental nonprofit(非盈利机构), according to The New York Times. “When you look at the genetic sequence(基因序列)of the virus, and you match it up with every known coronavirus, the closest relatives are from bats,” Dazsak also told CNN.

So why are bats the source of so many deadly kinds of viruses but they don’t suffer from any symptoms? As the only flying mammal(哺乳动物)with a long lifespan, bats’ body temperature is high, similar to a fever. It’s the fact that may contribute to bats’ unique immune system in protecting them from the ill effects of viruses.

But are bats truly to blame for the virus-or should we be blaming ourselves? Whether we destroy the forests where bats live or they end up on our plate, it’s the fault of humans for decreasing the distance between us and virus-carrying bats. Bats are an important animal in our ecosystem when it comes to pollinating(授粉)many fruits such as mangos and bananas. We need to allow them to continue pollination and keep them away from our markets and mouths.