Pesticides were created as a way to increase crop yield and yet they are beginning to have the opposite effect. The pests that the chemicals were meant to kill have defenses in place that help them defend themselves against plants' natural chemical barriers and therefore the pests are built to detoxify. Bees, a species that evolved parallel to flowers in a symbiotic relationship, do not have adaptations built up against natural chemicals and are therefore made even more vulnerable in the face of pesticides.
Neonicotinoids
Neonicotinoids were released as a family of pesticides in the 1990s and quickly became one of the most popular pesticides in the world. They have since been banned in some countries. The fact that they are still used at all is bad news for bees because a multitude of studies have proven these to be some of the most dangerous pesticides for pollinators, particularly bees. A factor in this danger is that these pesticides are designed to infiltrate a plant in its entirety and therefore are found in the pollen and nectar that the bees eat and take back to the hive to feed others. The main focus within these next sections are the impacts of Neonicotinoids but the word pesticide is more often used as a reminder that neonicotinoids aren't the only culprits contributing to bee decline.
Negative impact on bees
The FirstThe most severe case of poisoning by pesticides leads to death. Studies have shown that the cloud of chemicals around seeding machinery is equal to 1000 times the lethal quantity for bees. It is also necessary to consider that some pesticides when combined in an area are up to 5 times more toxic to bees.
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The SecondPesticides at sub lethal levels have been shown to impact the cognitive function of bees, impairing foraging ability, causing memory loss, and decreasing motor skills. These functions are necessary for survival. Without these abilities, the bees cannot find food, make it back to their hive/nest, and communicate with other bees.
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The ThirdThere are many biological impacts of neonicotinoids which include enhancing virus impacts, decreasing longevity, lowering fertility, inhibiting development of the glands used to produce royal jelly (used to feed the hive), and harming respiratory pathways as well as metabolic pathways. These side effects lead eventually to untimely death or a decrease in the ability to perform necessary tasks and continue the species.
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All of these impacts will put stress on a hive of bees. Undue stress then decreases the longevity of the workers and can lead to the failure of a hive. For solitary bees their populations will continue to decrease as they experience these issues.
Warning!
Do Not Be confused by the term sub-lethal. pesticides that don't immediately kill bees often lead to the life threatening conditions listed above!
Beware of SYNERGISTIC Interactions: interactions in which The product of Mixing two pesticides is more potent than the reactants by themselves at the same dose.
What's more, some chemicals INTERFERE with the honeybee's ability to produce honey!
An Incomplete List Of Harmful chemicals
Common Neonicotinoids |
Other harmful pesticides |
imidacloprid, (C9H10ClN5O2)
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pyrethroid (C21H28O3): insecticide
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*essential oils help are a prime examples that many chemicals even organic ones
confuse bee's over 100 odor receptors(varies by species) this confusion causes them not to return home
confuse bee's over 100 odor receptors(varies by species) this confusion causes them not to return home
PICK YOUR POISONInG
Nine ways pesticides enter a bee's environment
- Bees can be directly exposed to the spray of pesticides during the application process (this is often deadly).
- After plants are sprayed with pesticides the bee may consume contaminated pollen or nectar (more impact on native bees).
- Bees also are exposed through contact with residue on leaves and petals.
- Pesticides often contaminate non-target sites such as the nesting ground and nesting material of solitary bees.
- Pesticide residue also makes its way into water sources such as puddles, lakes and streams that bees use.
- Pesticides are also commonly found in the guttation fluids of plants (part of the moisture on the ground in the morning) bees may be exposed to this fluid as they pollinate.
- The wind can aid in the exposure of bees to pesticides, as residue can be blown to non target sites.
- Pesticides are long lasting and can sometimes last on plants for months or even years
- Once pesticides find their way into the hives they do not cycle out quickly. Pesticides can be stored in wax and reserve food supplies for long lengths of time. Then if a honey bee colony is forced by climate change or other factors to resort to eating the stores, they will once again be exposed to the pesticide.