Subtitles section Play video Print subtitles There is an environmental mystery afoot, and it begins with a seemingly trivial detail that reveals a disaster of global proportions. One day, you notice that the honey you slather on your morning toast is more expensive. Instead of switching to jam, you investigate the reason for the price hike. What you find is shocking. The number of domesticated honeybees in the US has been decreasing at an alarming rate. This decline appears too big to be explained by the usual causes of bee death alone: disease, parasites or starvation. A typical crime scene has almost no adult bees left in the hive, except, perhaps, a lonely queen and a few other survivors. It's full of untouched food stores and a brood of unborn larvae, suggesting that the adults vacated without waiting for them to hatch. But what's particularly eerie is that there's no tell-tale mass of dead or dying bees nearby. Either they have forgotten their way back to the hive, or they have simply disappeared. These mysterious disappearances aren't new. Humans have been collecting honey for centuries. But it wasn't until European settlers in the 1600's introduced the subspecies, Apis mellifera, that we domesticated bees. Since the 19th century, beekeepers have reported occasional mass disappearances, giving them enigmatic names like disappearing disease, spring dwindle disease and autumn collapse. But when in 2006 such losses were found to affect more than half of all hives in the US, the phenomenon got a new name: colony collapse disorder. The most frightening thing about this mystery isn't that we'll have to go back to using regular sugar in our tea. We farm bees for their honey, but they also pollinate our crops on an industrial scale, generating over 1/3 of America's food production this way. So, how can we find the culprit behind this calamity? Here are three of the possible offenders. Exhibit A: Pests and Disease. Most infamous is the varroa mite, a minuscule red pest that not only invades colonies and feeds on bees, but also transfers pathogens that stunt bee growth and shortens their life span. Exhibit B: Genetics. The queen is the core of a healthy hive. But nowadays, the millions of queen bees distributed in commercial hives are bred from just a few original queens, which raises the worry about a lack of genetic diversity which could weaken bees' defenses against pathogens and pests. Exhibit C: Chemicals. Pesticides used both on commercial beehives and agricultural crops to ward off parasites could be getting into the food and water that honeybees consume. Researchers have even found that some pesticides damage the honeybees' honing abilities. So we have a file full of clues but no clear leads. In reality, scientists, the actual detectives on this case, face disagreement over what causes colony collapse disorder. For now, we assume that several factors are the cause. Honeybees aren't necessarily in danger of extinction, but fewer bees overall means less pollination and higher food costs, so it's crucial that scientists solve the case of the vanishing bees. Because while having less honey might be a buzzkill, crop shortages are something that would truly sting.