The Worlds Bees are Disappearing?

http://www.environmentalgraffiti.com/animals/news-doctor-says-bees-have-left-building%E2%80%A6-er%E2%80%A6-solar-system-0

Environmentalists all over the world are trying to figure out as to why the number of honeybees, our number one pollinator, is disappearing. This is not only happening in the United States, but also in England, Germany, Austria, Switzerland, Sweden, and Japan.

Over the past twenty years, more than one million hives have mysteriously disappeared, and this number is still decreasing today. Although many might not worry for after all you would not get stung as often, this is a serious matter. According to Albert Einstein, without bees, the Earth would not last more than four years. Although the blue planet we call "home" will not completely parish, we would lose a very important insect, vital to the human food chain. Without them, there would be no flowers, nuts, fruits, etc.

Even worse, in less deveoped countries, which depend on natural polination would begin to lower in numbers, for there would be no bees to polinate the plants and continue "creating" more, therfore stopping the production of new fruits/vegetables, putting the countries at risk for starvation. Many people do not know how, and why they are disappearing, although there are a few with thoeries. Some scientists believe that they are living in unhealthy conditions, with lice/mites, and large amounts of heat. However, there are others who claim the radiation of cell phones mess with their "internal guiding systems" which ensure the bee gets back to the hive. There are studies in which a cell phone was placed near a hive, and bees that have left would not return, being unable to find their way back.

Response: I believe that this is horrible, for without them, there would be no vegetarians, no herbivores, etc. I am glad that scientists are conducting studies in order to learn the cause of their disappearance, so that we may be able to stop them, before we have to risk the extinction of one of natures most important animals.

Questions: 

1. By how much has the number of bees decreased?

2. Why may cellphones be the cause of their disappearance?

3. Why are bees so important?

4. How long would the Earth last without bees?

5. What would happen to the less developed countries?