It seems kind of anti-productive in terms of survival for a plant to produce an addictive chemical as that plant will constantly be sought after by animals that ingest it. In this instance, I'm looking for a possible general & inclusive answer here that would describe most plants that make this. Not a specific instance (although if provided as an example would be a plus).
To appreciate the scope of this is terms of number of plants producing potentially addictive compounds - see this compendium:
compendium of botanicals reported to produce toxic, physchoactive or addictive compounds
It's a matter of perspective. Most of the chemicals that are addictive to us humans (particularly alkaloids), and may be addictive for some other animals as well, are also insecticides. Lots of plants that we consider poisonous are good food for other species, and lots of plants that insects would consider poisonous are treats for us.
This is a great example of the aimless nature of evolution. The plants that could successfully defend themselves against insects stabilize on a solution that happens to be bad for them in certain ways. Although, you would be hard pressed to find a better way to guarantee reproduction than being addictive to humans.
Also of interest
As someone commented earlier, chemicals such as nicotine and morphine were products of evolution meant to repel animals. It is explained in more details in this article here.
Evolutionary biologists studying plant-herbivore interactions have convincingly argued that many plant secondary metabolites, including alkaloids such as nicotine, morphine and cocaine, are potent neurotoxins that evolved to deter consumption by herbivores.
But it seems that those same chemicals produce adverse effects to what they were originally intended for:
For example, one or more plant alkaloids have been identified that interfere with nearly every step in neural signalling. Targets include neurotransmitter synthesis, storage, release, binding, deactivation and reuptake, ion channel activation and function, and key enzymes involved in signal transduction.
Paradoxically, the same properties invoked to explain why common drugs like caffeine, nicotine and cocaine are toxic are also those invoked to explain why these compounds are rewarding. It is therefore important to stress that these and other addictive drugs appear to have evolved only because they successfully deterred, not rewarded or reinforced, plant consumption.
For example, let's take a closer look at nicotine. This compound is not present at all times in the plant, instead it is produced as a reaction to a trigger.
Nicotiana attenuata is an important model species for the analysis of plant-herbivore interactions involving nicotine. It is a domesticated North American tobacco plant that is attacked by over 20 different herbivores, ranging from mammalian browsers to intracellular-feeding insects. These attacks elicit a battery of defensive responses, including nicotine production.
Nicotiana has therefore evolved to allocate chemical defences strategically by concentrating them in the most valuable parts of the plant, such as young leaves, stems and reproductive organs, and by modulating its production according to the type of herbivore and extent of leaf damage.
This last example concentrates on nicotine, but it makes it easier to grasp how plants might use the production of such a chemical as a mean of protection.
Also, depending on the substance and the creature which consumes the plant, one might witness different outcomes. I found interesting information in this less detailed text here:
Defensive compounds from plants, like nicotine and cocaine, usually target nervous system components in insects. These components include proteins that have important roles on the insect's physiology, which may include specific receptors, ion channels, enzymes, etc. In most cases, the defensive chemical kills the insect by interfering with one or more of these proteins; in other cases, the chemicals just make the plant distasteful for the insect, and therefore, the bug will leave the plant alone.
I am providing an example which somewhat contradicts the points mentioned in the other answers regarding toxicity of alkaloids to insects.
Caffeine is a stimulant and is toxic at high doses (also for humans) but at low doses it has a stimulating pharmacological effect on the organism. The same principle applies to insects as well. A study by Wright et. al (2013) has revealed that caffeine in the nectar of some flowers, enhances the bee's memory of that flower (a reward, in general).
They have also mentioned that:
Two caffeine-producing plant genera, Citrus and Coffea, have large floral displays with strong scents and produce more fruits and seeds when pollinated by bees (8, 9)
However, caffeine tastes bitter and bees would reject nectar (sugar solutions) containing high levels of caffeine (>1mM).
The appearance of psychoactive compounds in plants has nothing to do with their addictiveness in man.
Psychoactive plants were there long before humans. The question therefore should be: "Why would humans evolve brains that exhibit addictive propensity to poisonous compounds abundantly available in nature"? The answer is: because our brain evolved in the absence of addictive substances.
One has to realize that addictive compounds are grown and processed. When humanoids evolved over millions of years, for the larger part there were no means to grow, harvest and process coffee beans, tobacco and coca leaves. Moreover, the most addictive drugs like injectable heroin and smokable cocaine (crack) are chemically purified. Methamphetamine and many addictive opiates are purely synthetic. In their native form, coca leaves and poppies are far less addictive, because in the raw form they lack the dopamine rush. Instead, the chewing of raw plant materials like coca leaves produces a mild high with a slow onset, and a mild offset. The sudden dopamine rush is what evokes the blissful euphoric state chased by heroin, crack and meth addicts, while the dreadful crash associated by these purified drugs is one of the strong motivators to seek for another hit. Also note that tobacco is heavily processed through a curing process before it is sold. The raw, woody tobacco products are far less likely to cause addiction.
Moreover, note that many of the addictive stuff originates from the Americas (coca) and Asia (opiates). Humans came from Africa. Africa is one of the continents with very, very few drug containing plants (Qat being the exception - a mild drug).
Most people know that cigarettes and other tobacco products are addictive, but many people do not understand the role of nicotine in tobacco addiction, disease, and death. Nicotine is what addicts and keeps people using tobacco products, but it is not what makes tobacco use so deadly. Tobacco and tobacco smoke contain thousands of chemicals. It is this mix of chemicals—not nicotine—that causes serious disease and death in tobacco users, including fatal lung diseases, like chronic obstructive pulmonary disease (COPD) and cancer. 1
Addiction: Using any tobacco product containing nicotine can lead to nicotine addiction. This is because nicotine can change the way the brain works, causing cravings for more of it. Some tobacco products, like
cigarettes, are designed to deliver nicotine to the brain within seconds, 2 making it easier to become dependent on nicotine and more difficult to quit. While nicotine naturally occurs in the tobacco plant itself, some tobacco products contain additives that may increase the absorption of nicotine. 3
Adolescent Brain Development: Although many teens underestimate how easy it is to become addicted to nicotine, young people are the most at risk for nicotine addiction because their brains are still developing. In fact, the younger a person is when they start using tobacco, the more likely they are to become addicted. 4 Nicotine exposure during adolescence can disrupt normal brain development and may have long-lasting effects, such as increased impulsivity and mood disorders. 4 Because of nicotine’s powerfully addictive nature and profound effects on the developing brain, no tobacco products are safe for youth to use.
Pregnancy and Fetal Health: If pregnant women use tobacco products, nicotine can cross the placenta and result in multiple adverse consequences. These outcomes may include, but are not limited to: premature labor low birth weight respiratory failure at birth and even sudden infant death syndrome (SIDS). 1, 5, 7, 8
Why would a plant evolve to produce an addictive chemical? - Biology
Predator/prey coevolution can lead to an evolutionary arms race.
Consider a system of plant-eating insects. Any plant that happens to evolve a chemical that is repellent or harmful to insects will be favored. But the spread of this gene will put pressure on the insect population and any insect that happens to have the ability to overcome this defense will be favored. This, in turn, puts pressure on the plant population, and any plant that evolves a stronger chemical defense will be favored. This, in turn, puts more pressure on the insect population. and so on. The levels of defense and counter-defense will continue to escalate, without either side "winning." Hence, it is called an arms race. This sort of evolutionary arms race is probably relatively common for many plant/herbivore systems.
Other predator/prey systems have also engaged in arms races. For example, many molluscs, such as Murex snails, have evolved thick shells and spines to avoid being eaten by animals such as crabs and fish. These predators have, in turn, evolved powerful claws and jaws that compensate for the snails' thick shells and spines.
Aloe vera is the thick juice of the aloe, a type of plant that comes from tropical Africa but is also cultivated elsewhere. The juice contains a chemical called alonin, that has been used in cosmetics and medicine. Its healing properties have made it especially useful as an ingredient for lotions and gels that soothe burns, including sunburn. It can also be used to repel biting insects.
Also known as toothpickweed, this Mediterranean herb contains a chemical that opens up blood vessels, improving blood flow to the heart, and opens the breathing tubes of the lungs. The chemical has been used in medicines to treat asthma and angina (pain due to heart problems).
The Madagascar periwinkle is the source of drugs used to treat diabetes and certain cancers, such as Hodgkin?s disease and acute leukaemia. The drug for treating Hodgkin?s disease has increased patients? chances of survival from one-in-five to nine-in-ten.
The bark of this tropical tree contains a drug called quinine. Quinine is used in the prevention and treatment of malaria, a deadly disease carried by mosquitoes. Malaria is responsible for thousands of human deaths around the world every year.
This little plant contains a chemical called colchicine, which has been used to treat rheumatism and gout. As it tends to prevent cells from dividing too quickly, colchicine has also been used to suppress some types of cancer
The coca plant grows naturally in South America and is the source of the drug cocaine. Although cocaine can be abused and is associated with addiction, it has also been used responsibly by doctors as a local anaesthetic and for pain relief.
Opium is a pain-killing drug extracted from the unripe seed pods of the opium poppy. In 1806, a German scientist isolated the drug morphine from opium. Morphine and its derivatives, such as heroin and codeine, remain important pain relievers.
Meadowsweet is a European wildflower that grows in wet soils and marshes. It has been used for pain relief in the treatment of many conditions, including headaches, arthritis, and rheumatism.
Rauvolfia is a small, woody plant that grows in tropical rainforests. It contains reserpine, a chemical that effectively relieves snake bites and scorpion stings. Reserpine was the first tranquillizer used to treat certain mental illnesses. It also lowers blood pressure.
Polyketides and Other Secondary Metabolites Including Fatty Acids and Their Derivatives
18.104.22.168 Metabolism by Plant Tissues
Isoflavonoids may not be end products of plant metabolism . In addition to demonstrating their mobilization from vacuolar stores and subsequent metabolism (often to more highly modified isoflavonoid derivatives, see above), some studies have documented metabolism of endogenously applied isoflavonoids by plant tissue. However, the presence of contaminating microorganisms can seriously compromise the interpretation of such experiments. For example, studies with chickpea and mungbean seedlings indicated half lives for exogenously added daidzein ( 4), formononetin (5) or coumestrol (9) of ∼50 h. However, repeating these experiments with sterile mung bean seedlings revealed little appreciable metabolism of (5) (95% recovery after 24 h), although [ 14 C]-(4) was rapidly metabolized (8.5% recovery) with label incorporated into most cellular/chemical fractions, including the cell wall. 257
The interconversions of medicarpin (6) and its corresponding isoflavan vestitol (8) in alfalfa and red clover 102,103 have been described above. Ring opening of a pterocarpan to yield the corresponding isoflavan (110) has also been reported when phaseollin (17) is fed to bean cell suspension cultures, 258 and this is accompanied by the opening of the ring formed from the cyclized prenyl side chain. Compound (17) is also converted to (110) by the fungal pathogen Septoria nodorum. 259
The role of isoflavonoid degradation as a factor in the elicitor- and pathogen-induced accumulation of isoflavonoid phytoalexins received considerable attention when it was proposed that elicitation by abiotic elicitors or incompatible races of pathogens was associated with strongly inhibited phytoalexin degradation (assessed using exogenously applied radiolabeled phytoalexin), whereas an increased biosynthetic rate was the major factor determining phytoalexin levels in response to biotic elicitors. 260,261 These conclusions were challenged when it was demonstrated, using 14 CO2 labeling in vivo, that the half-lives of glyceollin (18) and its trihydroxypterocarpan precursor (87) were long, ∼100 h and ∼38 h, respectively. 262 Apparently, the metabolic fates of exogenously applied and endogenously synthesized glyceollin are different. Studies of isoflavonoid turnover have subsequently been eclipsed by the vast body of work on the induced biosynthesis of these compounds, and more studies are needed to determine the biological half-lives and metabolic fates in planta of biologically active isoflavonoids.
What is addiction?
Many people consider addiction to be a problem of personal weakness, initiated for self-gratification and continued because of an unwillingness or lack of sufficient willpower to stop. However, within the medical and scientific communities, the notion that pleasure-seeking exclusively drives addiction has fallen by the wayside. Clinicians and scientists alike now think that many people engage in potentially addictive activities to escape discomfort — both physical and emotional. People typically engage in psychoactive experiences to feel good and to feel better. The roots of addiction reside in activities associated with sensation seeking and self-medication.
People allude to addiction in everyday conversation, casually referring to themselves as “chocolate addicts” or “workaholics.” However, addiction is not a term clinicians take lightly. You might be surprised to learn that until the current Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), the term addiction did not appear in any version of the American Psychiatric Association’s diagnostic manual, the reference book that physicians and psychotherapists use to identify and classify mental health disorders. In this most recent edition, addiction is included as a category and contains both substance use disorders and non-substance use disorders, such as alcohol use disorder and gambling disorder, respectively.
A revised view of addiction
It might seem strange to group gambling problems in the same category as a problem with drugs or alcohol. But addiction experts are beginning to move away from the notion that there are multiple addictions, each tied to a specific substance or activity. Rather, the Syndrome Model of Addiction suggests that there is one addiction that is associated with multiple expressions. An object of addiction can be almost anything — a drug or drug-free activity. For addiction to develop, the drug or activity must shift a person’s subjective experience in a desirable direction — feeling good or feeling better.
Several scientific advances have shaped our contemporary understanding of this common and complex problem. For example, brain-imaging technologies have revealed that our brains respond similarly to different pleasurable experiences, whether derived from ingesting psychoactive substances, such as alcohol and other drugs, or engaging in behaviors, such as gambling, shopping, and sex. Genetic research has revealed that some people are predisposed to addiction, but not to a specific type of addiction.
These findings suggest that the object of addiction (that is, the specific substance or behavior) is less important than previously believed. Rather, the new thinking reflects the belief that addiction is functional: it serves while it destroys. Addiction is a relationship between a person and an object or activity. With addiction, the object or activity becomes increasingly more important while previously important activities become less important. Ultimately, addiction is about the complex struggle between acting on impulse and resisting that impulse. When this struggle is causing suffering related to health, family, work, and other activities of everyday life, addiction might be involved.
There are many routes for recovery, and the road may take time
Addiction is a chronic and often relapsing disorder. It is often preceded by other emotional problems. Nevertheless, people can and do recover from addiction, often on their own. If not on their own, people can recover with the help of their social network or a treatment provider. Usually, recovery from addiction requires many attempts. This can lead to feelings of frustration and helplessness. Smoking is often considered one of the most difficult expressions of addiction to change. Yet, the vast majority of smokers who stopped quit on their own! Others stopped smoking with the help of professional treatment. It is important to remember that the process of overcoming an addiction often requires many attempts. Each attempt provides an important learning opportunity that changes experience and, despite the difficulties, moves recovering people closer to their objectives. There are many pathways into addiction and many routes to recovery. Think about recovery from addiction as a five-year process that will have its ups and downs after about five years, life can and will be very different. As life becomes more worth living, addiction loses its influence.
Acacia plant controls ants with chemical
In Africa and in the tropics, armies of tiny creatures make the twisting stems of acacia plants their homes.
Aggressive, stinging ants feed on the sugary nectar the plant provides and live in nests protected by its thick bark.
This is the world of "ant guards".
The acacias might appear overrun by them, but the plants have the ants wrapped around their little stems.
These same plants that provide shelter and produce nourishing nectar to feed the insects also make chemicals that send them into a defensive frenzy, forcing them into retreat.
Nigel Raine, a scientist working at Royal Holloway, University of London in the UK has studied this plant-ant relationship.
Dr Raine and his colleagues from the universities of St Andrews, Edinburgh and Reading in the UK and Lund University in Sweden have been trying to work out some of the ways in which the insects and the acacias might have co-evolved.
He explains how the ants provide a useful service for the acacias.
"They guard the plants they live on," said Dr Raine. "If other animals try to come and feed on the rich, sugary nectar, they will attack them."
In Africa, one type of ant-guard, known as Crematogaster , will even attack large herbivores that attempt to eat the plant.
"If a giraffe starts to eat the leaves of an acacia that is inhabited by ants, the ants will come out and swarm on to its face, biting and stinging," says Dr Raine.
"Eventually, the giraffe will get fed up and move off."
In the New World tropics, the Pseudomyrmex genus of ants fulfil a very similar guarding role.
For both species, the acacias provide little, reinforced structures that the ants hollow out and nest within, as well as sugar-rich nectar for them to eat.
"In return, both groups of ants protect their host plants from herbivores - both hungry insects and larger [animals]," explains Dr Raine.
That is the plus side for the plants. But being inhabited by aggressive insects could make one important aspect of a plant's life difficult - flowering.
Flowers need to be pollinated so the plant can reproduce. So what stops the ants from attacking the helpful little pollinators or stealing all the tasty nectar that attracts them?
"Some plants do this structurally, with physical barriers to stop ants getting on to the flower, or sticky or slippery surfaces that the insects can't walk on," said Dr Raine.
"Acacias don't have these barriers. They have very open flowers, but still, the ants don't seem to go on to them. We wanted to know why."
One clever approach by the plant is a food "bribe". "Extrafloral nectaries" are small stores of nectar on stems, from which the inhabitants can feed without going on to the flowers.
Acacias also produce structures called beltian bodies on the leaf tips.
These, Dr Raine explains, are nutritious structures produced by the plant to feed its resident colony of ant-guards.
But when this isn't enough, it is a case of chemical warfare.
Flowers can produce a variety of chemicals. We can smell some of the volatile organic compounds they release when we sniff our favourite summer bloom.
But there is a more manipulative side to these scents.
Floral volatile compounds can act as signals - drawing in pollinators such as bees and hummingbirds in with their irresistible aromas.
To the ants, however, they are far from irresistible.
"The flowers seem to produce chemicals that are repellent to the ants," said Dr Raine. "They release these particularly during the time when they're producing lots of pollen, so the ants are kept off the flowers."
In recent studies, described in the journal Functional Ecology, Dr Raine and his colleagues found that the plants with the closest relationships with ants - those that provided homes for their miniature guard army - produced the chemicals that were most effective at keeping the ants at bay.
"And that was associated with the flower being open," he says. "So the chemicals are probably in the pollen."
When the pollen has all been taken away - by being brushed on to the bodies of hungry pollinators and helpfully delivered to other plants - the flowers become less repellent.
"So at this point, the ants can come on to the flowers and can protect them from other insects that might eat them, so that the developing seeds aren't lost," he explains.
Dr Raines' team was able to test this using young flowers that had just opened and that contained lots of pollen.
The scientists wiped them on older flowers and on the acacia's stems.
This showed them that the effect was "transferrable" - the stems and older flowers that had been wiped became more repellent.
"It gives this really neat feedback system - the plant is protected when it needs to be protected, but not when it doesn't."
The repellent chemicals are specific to the ants. In fact, they attract and repel different groups of insects.
"[The chemicals] don't repel bees, even though they are quite closely related to ants. And in some cases, the chemicals actually seem to attract the bees," says Dr Raine.
The researchers think that some of the repellents that acacias produce are chemical "mimics" of signalling pheromones that the ants use to communicate.
"We put flowers into syringes and puffed the scent over the ant to see how they would respond, and they became quite agitated and aggressive" he explained.
"The ants use a pheromone to signal danger if they're being attacked by a bird they will release that chemical that will quickly tell the other ants to retreat."
Dr Raine says this clever evolutionary system shows how the ants and their plants have evolved to protect, control and manipulate each other.
The ants may be quick to swarm, bite and sting, but the harmless-looking acacias have remained one step ahead.
How does a plant systematicist study a plant taxon?
Plant scientists can select a taxon to be analyzed, and call it the study group or ingroup. The individual unit taxa are often called Operational Taxonomic Units, or OTUs.
How do they go about creating the "tree of life"? Is it better to use morphology (physical appearance and traits) or genotyping (DNA analysis)? There are benefits and disadvantages to each. The use of morphology may need to take into account that unrelated species in similar ecosystems may grow to resemble one another in order to adapt to their environment (and vice versa as related species living in different ecosystems may grow to appear differently).
It is more likely that an accurate identification can be done with molecular data, and these days, performing DNA analyses is not as cost prohibitive as it was in the past. However, morphology should be considered.
There are several plant parts which are particularly useful for identifying and segmenting plant taxa. For example, pollen (either via the pollen record or pollen fossils) are excellent for identification. Pollen preserves well over time and is often diagnostic to specific plant groups. Leaves and flowers are often used as well.
Angiosperms first appear in the fossil record about 130 million years ago, and by 90 million years ago they had become the predominant group of plants on the planet. English naturalist Charles Darwin considered the sudden appearance of angiosperms to be an "abominable mystery," and scientists have debated about the origin of the group for many years. Comparative studies of living species suggest that angiosperms evolved from the gnetophytes, a group of gymnosperms with three living genera of rather strange plants: Ephedra, Gnetum, and Welwitschia. Double fertilization has been shown to occur in both Ephedra and Gnetum, and the reproductive structures (strobili) of all three genera are similar to the flowering stalks of some angiosperms. Some gene sequencing studies also indicate that gnetophytes and angiosperms are closely related to each other and to an extinct group of gymnosperms called the Bennettitales. However, more recent molecular studies suggest that gnetophytes are more closely related to conifers than they are to angiosperms.
In 1998, the discovery of an angiosperm-like fossil called Archaefructus, which apparently existed 145 million years ago, also cast some doubt on the idea that angiosperms descended from gnetophytes or Bennettitales. Although a great deal of information has been obtained since the time of Darwin, the origin of angiosperms is still something of a mystery.
The Advance of Pesticides Through the 20th Century
The primitive tools now had scientific reasoning to explain their efficacy and identify their chemical formulations, moving them from the realm of natural extracts to synthesized pesticides, and signaling the rise of the chemical pesticide revolution. Pest control, which had begun with simple tools and methods, was refined over centuries and completely reborn during World War II. The late 19th and early 20th century world of the first synthetic organic chemicals gave rise to the first modern synthetic pesticides in the form of organochloride compounds.
Many organochloride compounds, such as BHC and DDT, were first synthesized in the 1800s, but their properties as insecticides were not fully discovered and exploited until the late 1930s. BHC (Benzene hexachloride) was first produced by the English scientist Michael Faraday in 1825, but its properties as an insecticide were not identified until 1944. DDT (dichlorodiphenyltrichloroethane) was first prepared by Othmar Ziedler, an Austrian chemist, in 1825, but the Swiss chemist Paul Hermann Müller did not discover DDT’s insecticidal properties until 1939 — a discovery that led to Müller’s award of the Nobel Prize in 1948.
DDT’s use as a pesticide proved to be a huge boon to war efforts. Prior to the discovery of DDT, pyrethrins were among the major insecticides in use. But pyrethrins were extracted from natural sources, primarily from flowers of the genus Chrysanthemum (Pyrethrum), supplies of which were limited and insufficient to meet the demands of wartime use. It was due to this shortage that DDT, instead, became the Allied Forces’ insecticide of choice to control insects that were vectors for typhus, malaria and dengue fever.
At the time, DDT was seen as a broad-spectrum insecticide with low toxicity to mammals. It was inexpensive to produce, easy to apply to large areas, and was persistent, so that reapplication was generally not needed DDT is insoluble in water and therefore not washed away by weather. The compound also appeared, at first, to be incredibly effective at eliminating the insect vectors of disease, which led it to be hailed as a wonder insecticide.
In 1962 Rachel Carson, a marine biologist and conservationist, published Silent Spring, a book that highlighted the detrimental effects of pesticides on the environment.
By 1945, DDT was made available for agricultural applications. But the first signs of insect resistance to DDT began to appear in the 1950s. In 1962 Rachel Carson, a marine biologist and conservationist, published Silent Spring, a book that highlighted the detrimental effects of pesticides on the environment. The widespread popularity of Carson’s book led to the establishment of influential grassroots organizations that called for greater environmental protections and stricter controls on pesticide use. Part of that call to change was the reduction or elimination of DDT and many other pesticides developed from the 1940s through the 1960s from the pest-fighting arsenal.
DDT remained in widespread use around the world until the 1980s, but its decline hastened once the U.S. Environmental Protection Agency (EPA) canceled most uses of DDT by 1972. Many other countries followed suit shortly thereafter by removing DDT from lists of approved agricultural applications. In 2004, the Stockholm Convention outlawed many persistent organic pollutants (POPs) and restricted the use of DDT to vector control (primarily for malaria). Despite increasing worldwide restrictions and bans on DDT, as of 2008, India and North Korea were still using DDT in agricultural applications. Today, India is the only country in the world still producing DDT.
Since the start of the production boom in the 1940s to present day, a huge catalog of thousands of insecticides, herbicides, and general pesticides was developed, including organochlorides (DDT, BHC), organophosphates (Parathion, Malathion, Azinophos Methyl), phenoxyacetic acids (2,4-D, MCPA, 2,4,5-T), Captan, Carbamates (Aldicarb, Carbofuran, Oxamyl, Methomyl), neonicotinoids (Imidacloprid, Acetamiprid, Clothianidin, Nitenpyram), and Glysophates.
The neonicotinoids are neuro-active insecticides, similar to nicotine compounds that were developed in the 1980s and 1990s. Of all the neonicotinoids, Imidacloprid has become one of the most abundantly used insecticides in the world. Patented in 1988 and registered with the EPA in 1994 by Bayer Crop Science, Imidacloprid works by disrupting the transmission of nerve impulses in insects by binding to an insect’s nicotinic acetylcholine receptors, resulting in paralysis and death. Imidacloprid is highly toxic to insects and other arthropods, including marine invertebrates. It is considered to be moderately toxic to mammals if ingested at high dosages.
The acute toxicity and environmental fate of Imidacloprid and other neonicotinoid pesticides have been greatly debated since their adoption in the 1990s. Many studies have examined the persistence of neonicotinoids in water supplies and their ecological impacts on other environmentally and economically important arthropods. Studies published within the last two decades have linked bee colony collapse disorders with Imidacloprid and other similar pesticides. The most toxic pesticide in the world today for honey bees (genus Apis) is also the most commonly used insecticide in the world: Imidacloprid.
If Imidacloprid is the most widely used insecticide in the world, Glyphosate is the most widely used herbicide on Earth. Glysophate was developed by a Monsanto chemist, John E. Franz, in 1970. Roundup, as it was trademarked, quickly became one of the most popular herbicides in the world among both agricultural enterprises and home users. The mode of action for Glyphosate is to inhibit a plant enzyme that is integral to the synthesis of aromatic amino acids. The inhibition of the amino acid production affects primarily the growing regions of the plants, killing plants in their growth cycle but not in their seed stage.
In 1994, the Roundup Ready Soybean was commercially approved in the United States. This genetically engineered soybean was created to be resistant to glyphosate. These types of crops allowed for the use of glyphosate to control other pest plants without endangering the crop. The list of glyphosate-resistant crops has grown since the introduction of the Roundup Ready Soybean to include corn, canola, alfalfa, cotton, and wheat.