With the arrival of warmer temperatures and spring flowers, many people will turn their attention to summer gardens. Across the country, large-scale agriculture is busy producing the majority of the fruits and vegetables that end up on American tables and in restaurants.

For both home gardeners and agribusiness companies, the weather is a perennial challenge. But a new problem has emerged in recent years that has the potential to create shortages in the nation’s food supply.

The problem is with bees. For several years now, honeybees have been dying at alarming rates. Whatever is killing the bees, in some cases wiping out 40 percent or even 50 percent of hives, is not just a scientific mystery — it’s a serious threat to the production of fruits, vegetables and some nuts.

Bees are essential for pollination, as children learn in grade school. But most adults do not realize the extent to which modern food production is dependent on bees.

One example of the scale of the problem is found in the almond groves of California. To pollinate the 800,000 acres of almond trees planted in California requires 31 tractor-trailers full of beehives from the nation’s largest commercial beekeepers, located in Montana and South Dakota.

A major die-off of bees over the winter threatens this year’s harvest of almonds — a multimillion-dollar crop and big player in California’s agriculture economy.

And wild bees, which still pollinate about three-quarters of global food crops, are also threatened. International studies have found that wild pollinators are more effective than honeybees at pollination and maximizing crop yields. But scientists say nearly half of the wild bee species disappeared in the 20th century.

Some might wonder why people should care about bees — either honeybees or their wild cousins.

Beyond the critical role they play in pollination of many food crops and the threat that bee die-offs pose to food production, there is the “canary in the coal mine” theory.

Before modern air-quality detection systems monitored the air in underground mines, canaries were kept in cages in the mines. If toxic gases developed, but at levels not detectable by humans, the canaries became ill and acted as an early warning system to alert the miners.

Many believe that bees might well be acting as a canary or early warning of environmental conditions that could eventually threaten humans.

Some scientists, as well as commercial beekeepers, believe that a type of pesticide, known as neonicotinoids, could be responsible for the major beehive losses. But uncertainty remains: an earlier theory pointed to a virus.

Last month, beekeepers took action and sued the Environmental Protection Agency, pressing it to withdraw its approval of two widely used neonicotinoid pesticides.

And the problem is not just in California almond groves. Around Erie, honeybees pollinate fruit trees, blueberry bushes and a variety of vegetable crops. There too, beekeepers are reporting troubling losses.

Bees might be an afterthought for most people. But it’s worth remembering that they perform an important function in agriculture. And the bees are irreplaceable — pollination cannot be mechanized.

All species should be protected from man-caused harm. But the unexplained die-off of bees deserves serious attention because of the critical role pollination plays in food production, in the United States and around the world.