Bee populations in the U.S. and globally have been on the decline for years now, and many experts predict that as more pollinators like bumblebees die, it could cause serious damage to our food sources. And earlier this spring, researchers predicted that 2013 would be the year when the bee death toll would finally have immediately destructive consequences — there wouldn't be enough bees to pollinate all of the plants that make up the crops needed to feed the U.S. population. But there is no way those experts could have predicted the mass death of 25,000 Oregon bees that has been occurring the past few days in a Target parking lot in Wilsonville. Early reports suggest that Oregon insecticides may be to blame for the death of the bees.

In a twist of situational irony, the dead bees were found on the same day that National Pollinator Week began — a "symbolic annual event intended to raise public awareness about the plight of bee," according to the Xerces Society for Invertebrate Conservation.

Photo: Rich Hatfield of The Xerces Society 2013 Conservationists report that 25,000 dead bees were found in a parking lot of an Oregon Target.

The bumblebees — along with a number of other pollinating bugs like honey bees and ladybugs — were found under European linden trees planted alongside the parking lot. According to Dan Hillburn, director of plants programs at the Oregon Agriculture Department, initial findings show that the trees were recently sprayed with an insecticide called Safari. The insecticide is definitely a threat to bumblebees, as its labeling states "This product is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area."

However, it remains unclear whether the insecticide is actually the cause of the bee massacre, and it may take another few days to determine with 100 percent accuracy why the bees died. One other possible cause of death could that this particular species of European linden is poisonous.

"If the trees are indeed toxic they should be cut down and replaced by something that will provide non-toxic pollen and nectar for bees," said Scott Hoffman Black, Executive Director at the Xerces Society. "On the other hand, if pesticides are the cause, we need to spotlight this as a real-world lesson in the harm these toxic chemicals are causing to beneficial insects." Black also pointed out the fact that the lindens are not agricultural crops — in other words, if pesticides were used on these trees, it would have been solely for aesthetic, superficial purposes, and would be providing zero health benefits to humans.

While officials await the results of testing, they have announced that bee-proof netting will be thrown over all the linden trees in an effort to prevent more bees from dying.

Native bumblebees are the most important pollinators in Western Oregon, helping berry and seed crops in the fertile Willamette Valley blossom, reproduce, and grow. The area is known for its grass seed, Christmas trees, and hazelnuts. In recent years, it has become one of the nation's top sources of beer and wine, producing some of the top beer hops and Pinot noir grapes in the U.S.

Photo: Rich Hatfield of The Xerces Society 2013 Pesticides are thought to be the cause of the 25,000 dead bees.

"To our knowledge this is one of the largest documented bumble bee deaths in the Western U.S.," said Rich Hatfield, a conservation biologist with Xerces. "It was heartbreaking to watch." Xerces estimates that the 25,000 dead bees make up 150 different bee colonies. It is unclear how much of an effect this massive bee death will have on this year's crops.

Seeing the Oregon bumblebees die in this way is particularly disturbing in light of the fact that in recent years, more and more cases of what has been termed "colony collapse disorder," when worker bees from a honey bee colony abruptly disappear and decimate the colony, have occurred. In 2006, for example, beekeepers reported losing massive amounts of their hives: between 30 and 90 percent of bees went missing. Recent years have seen similar trends. In total, the U.S. Department of Agriculture (USDA) estimates that honey bee colonies have decreased from five million in the 1940s to 2.5 million today, while crops that require honey bee pollination have grown exponentially. In other words, less bees have more work to do.

The dwindling honey bee population has a direct effect on public health: about "one mouthful in three in our diet directly or indirectly benefits from honey bee population," according to the USDA. The cause of the global bee population decline is unclear. The leading suspect is agricultural pesticides — like Safari — but other potential causes are under investigation as well.

"Undernourished or malnourished bees appear to be more susceptible to pathogens, parasites, and other stressors, including toxins," says a 2012 USDA report. In the report, the USDA suggested that beekeepers and scientists prepare for the worst: importing Russian honey bees and other bee breeds to help build up better resistance to colony collapse disorder, and stockpiling bee semen and germplasm, in case an even greater mass die off comes to pass.

Photo: Rich Hatfield of The Xerces Society 2013 Although the bumblebees are small, they have a huge impact: these 25,000 dead bees represent 150 colonies, and their death could ruin Western Oregon's crops this year.