Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. POISONS Crops pollinated by bees include almonds, apples, apricots, avocados, blueberries, cantaloupes, cashews, coffee, cranberries, cucumbers, eggplants, grapes, kiwis, mangoes, okra, peaches, pears, peppers, strawberries, tangerines, walnuts and watermelons. Seeds coated with neonicotinoid pesticides , or neonics, sprout into crops laced with the chemicals, which shut down the nervous system of any insect munching on the plant. The chemicals even make their way into nectar and pollen, which can dose bees with enough of the toxin to cause disorientation and a loss of ability to learn and communicate — crucial skills for a social insect. The poisons can be even stronger when store-shelf insecticides are used by home gardeners. Europe has temporarily banned neonics, the EPA is assessing these insecticides and will finalize regulatory action by the end of 2018. Western honeybee Apis mellifera

Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. PARASITES Honeybees are the targets of myriad pests, the most damaging of which is the varroa mite , a parasite that begins sucking the blood-like hemolymph of young bees soon after they hatch. The mite suppresses bee immune systems and transmits viruses. Honeybees from Africa are less susceptible to varroa, partly because they bite at the mites and try to remove them. Some commercial beekeepers have begun building hives with western honeybee queens that exhibit similar grooming behavior. A tiny phorid fly deposits her eggs inside a bee’s abdomen. A week later, the affected bee abandons the hive before a fly larva emerges from the doomed bee’s neck. Varroa destructor

Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. PATHOGENS Nosema ceranae spore Honey stomach Midgut Bees weakened by varroa mites or neonics appear to be more susceptible to a virulent new form of Nosema , a single-celled fungus that infects the cells lining the midgut of bees, reducing their ability to digest pollen. Spores are probably spread by bee feces. Infected worker bees abandon the colony, which greatly reduces the ability of the hive to gather food. Some evidence suggests that if bees are also infected with the invertebrate iridescent virus , the hive might be at even greater risk of collapsing. Scientists have found a strong correlation between collapsed hives and the presence of Israeli acute paralysis disease , a virus that arrived in bees imported to the United States.

Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. COMB CELL SIZE Natural-size cells are 4.9 mm across. “Standard-size” cells are 5.4 mm across. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 Natural-size bees are slightly smaller than most commercial bees. For more than a century, beekeepers have used unnaturally large fabricated honeycomb templates , or foundation, on which bees build their colonies. Larger comb cells produce bigger bees, but those bees tend to have compromised immune systems and their young bees take slightly longer to develop, which some scientific studies say gives varroa mites more time to infest young bees. A growing number of beekeepers now use smaller, natural-size cells and say that their bees are better able to deal with mites. Some studies back this up, but others say that cell size has no effect on mite infestations.

Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. MALNUTRITION When bees are trucked thousands of miles to pollinate large areas planted in a single crop, they can feed from only one type of flower, which puts them at risk for malnutrition. Puddles collect pesticides, dosing bees when they drop by for a drink. Watermelon flowers need at least eight visits from pollinators before they can develop big, round melons. A diverse diet from a broad range of flowers helps bees resist diseases. But that is not what many bee colonies find when they are transported to fertilize a single crop. Beekeepers sometimes supplement bee diets with high fructose corn syrup , which is chemically different from the fructose found in fruits and honey. HFCS is sometimes contaminated with mercury, a potent neurotoxin, and hydroxymethylfurfural, which can cause ulcers in bee intestines, leading to dysentery and early death. Pollen , the sole protein source for bees, has been shown to harbor as many as 46 different pesticides.

Studies show no links between colony collapse and either cellphone-tower radiation or genetically modified crops. GENETIC WEAKNESS, GLOBAL WARMING Bumblebees , which are the main pollinator of tomatoes, are vulnerable to many of the same pesticides, parasites and diseases that affect honeybees. Most queen honeybees in the U.S. come from a limited pool of breeder queens, which has led to poor genetic diversity . That makes them more susceptible to new pests and pathogens. Climate disruption can compound pressure on bee colonies. This year, Australia experienced its hottest summer ever recorded, resulting in a vast drought, which curtailed nectar and pollen production, reducing honey output by half and adding extra stress on hives.