lesson5 Sharing the Planet with Every Creature
Bees Are Dying
In March, 2017, cereal lovers in the United States were surprised to find that Buzz the Bee, the famous honeybee mascot of a cereal maker, was gone from the boxes of the maker's cereals. It was the decision of the cereal maker to remind people that the world's population of bees is fast diminishing. The cereal maker's decision did not come out of the blue. Earlier in that year, the U.S. Fish and Wildlife Service declared that in the United States the bumblebee was endangered. The population of the bumblebee in the U.S. had shrunk by nearly 90 percent since the late 1990s, according to the Wildlife Service. Similar phenomena have occurred in other parts of the world. In Central Europe, honeybee colonies have declined by 25 percent since 1985. In Hanyuan County, China, where pear and apple trees fill the landscape, farmers are forced to pollinate their fruit by hand due to the severe decline in the population of honeybees. All in all, bees are disappearing all over the world, and that worries scientists and farmers, among others. Why are they worrying? What is special about bees?
Bees are one of nature's most effective pollinators. If they do not move pollen from one blossom to another, one third of the crops we consume would be severely affected. They would have to be pollinated by other means, or they would produce significantly less food. Grains like wheat, rice, and corn are not much affected by the decline of bees because they are pollinated primarily by the wind. Fruits, vegetables, and some crops for farm animals, however, might disappear without bees. Apples, strawberries, watermelons ... the list is almost endless.
Why, then, are bees disappearing? There is general agreement among scientists that declines in bee populations are the product of multiple factors that can act alone or in combination. Roughly speaking, bee declines arise from three factors. The first one is sickness. Bees suffer from their own diseases and from parasites that weaken and often kill them. Many beekeepers agree that the parasitic mite, Varroa destructor, is the most serious threat to bees. Varroa is a very small mite that feeds on the blood of the bee and spreads from hive to hive. In addition to weakening the bees, Varroa can also spread diseases.
A second factor that is causing bee declines is poor nutrition. Bees feed on flowers, so they need a stable supply. When there are not enough diverse blooming flowers during the bee season, bees are not able to sufficiently feed themselves. The lack of diverse flowers is in part the result of changes in agriculture. Over the past century, agriculture has become increasingly industrialized. One of the outstanding features of industrial agriculture is monoculture, the agricultural practice of planting one crop in a given area year after year. Monoculture leads to poor nutrition for bees because a single plant cannot meet their nutrient requirements. "Bees need a varied diet of different types of pollen in order to grow into strong, healthy workers," explains Dr. Heather Mattila, a honeybee biologist at Wellesley College. Also, large industrial facilities, playgrounds, and golf courses are making matters worse by destroying bee habitats that were once filled with diverse flowers. "A green space can be a green desert unless it has flowering plants that are friendly to bees," Dr. Mattila adds.
One more suspected factor that is contributing to the bees' poor nutrition is climate change. Increasing temperatures, changes in rainfall patterns, and more irregular and extreme weather have impacted bee populations. For example, scientists in Poland have documented how honeybees are responding to changes in the climate. Their first winter flight date, the wakening moment after winter, has advanced by more than one month during the last 25 years due to increasing temperatures. Because patterns of flowering do not always match the bees' first winter flight, bees are likely to suffer from food shortages.
Widespread use of pesticides, common in industrial agriculture, is the third major factor that is leading to the decline of bees. There are several ways bees can be killed by pesticides. One of them is direct contact. When bees are on the flowers at the time of the application of a pesticide, the bees die immediately. In this case, the queen and the other bees in the hive are not affected and the colony survives.
If bees avoid direct contact with pesticides, they can still be contaminated through pollen, the air, water or soil. This has deadly effects on a bee colony because a contaminated bee transports the pesticide to the colony, in pollen or nectar, or on its body. The results are often disastrous, and the affected colony eventually collapses. Some pesticides do not affect adult bees, but do cause damage to young, immature bees. Other types of pesticides could affect bees' brains, making the bees slow learners and sometimes causing them to lose their ability to find nectar.
Several ways to protect bees from pesticides are being proposed. One of them is to apply pesticides in the evening. This will minimize the impact of pesticides on bees, as bees take food during the day. Certain crops such as melons and cucumbers have flowers that will be open for only a single day. For such crops, pesticides should be applied when the flowers are closed, as it will reduce the impact on bees. All in all, in order to protect bees from harmful pesticides, there should be national and international collaboration among beekeepers, growers, governments, and pesticide manufacturers.
As individuals, we can also help save bees. We can plant flowers in our gardens that are helpful for bees and try not to contaminate these flowers with pesticides. Also, we can buy and consume more organic produce that is grown without or with minimum use of pesticides. This way we can expect commercial growers to reduce their use of pesticides. When we take these seemingly small actions to help bees, we help them make our world healthier. In other words, we help ourselves by helping bees.
Supplementary Reading
What Happens When Something in a Food Chain Goes Extinct?
All living organisms hold a place in the food chain, structured around the transfer of energy needed for life through an ecosystem: from sunlight to plant to rabbit to fox to worm, to give a simple example. Because this energy transfer involves members of a food chain interacting with one another and with their environment, extinction of one species can have multiple effects on others.
Explosion of Prey Population
When a predatory species becomes threatened or extinct, this removes a check and balance in the food chain on the population of its prey. As a result, the prey population can explode. For instance, the huge increase in the deer population in the U.S. in the latter half of the 20th century stemmed partly from the diminished population of wolves.
Ripple Effect
Extinction of one species can threaten the existence of another species. In Britain, for instance, sheep kept the grass short in many regions. Short grass is the red ant's preferred habitat. When the sheep population diminished, the red ant population also shrank. In turn, the reduced red ant population led to the extinction of a butterfly species that feeds on red ant eggs.
Disrupted Habitat
The extinction of a species may alter the physical environment. For instance, the accidental introduction of the predatory brown tree snake to Guam wiped out 10 of the 12 native bird species on the island. Without birds to spread seeds, there may be fewer tree species in Guam's future, fundamentally changing its forest habitat.