Neonics & Pollinator Decline
Neonics & Pollinator Decline
How Neonics Spread
You can’t wash your hands of it
Neonics are a systemic pesticide. They can’t be washed off of our apples or rinsed from our garden flowers. They are inside the plant, having been taken up by the leaves or roots and distributed throughout by the vascular system. All parts of the plant are affected, including the stem, flowers, fruits, nectar and pollen. When insects ingest fluids or tissues from a treated plant, the neonics damage their central nervous system, causing tremors, paralysis and sometimes death.
Neonics are now the most widely used insecticides in the world with a global market value of billions of dollars annually. However, mounting evidence suggests unforeseen, negative effects on non-target species and the environment.
In our Environment
Neonics are highly soluble in water, which is the reason they can travel to all parts of a plant. They also last a long time both in the plant and the soil around it. This combination not only makes them desirable insecticides, but also potent environmental contaminants. Water can easily transport neonics throughout soils and into waterways. Once there, they take months (possibly years) to break down.
Neonics can now be found in some water bodies at levels that are toxic to aquatic insect species like midges and mayflies. This can cause serious disruptions in the food chain. In the Netherlands, declines of insects from neonics have been linked to declines of insect-eating birds. Birds can also be harmed directly if they eat neonic-coated seeds. In a Canadian study, migratory White-crowned Sparrows exposed to a dose of a neonic equal to four to eight treated canola seeds a day over three days lost a quarter of their body weight.
Depending on the concentration and mode of delivery of the neonic, it’s likely that many other species are harmed. Although amphibians and fish are less sensitive to neonics than insects, studies show neonics to be toxic to them at high doses, or after long exposures. Neonics can alter the eating patterns of earthworms to the point that they starve. Even bats may fall victim to neonics.
A Problem For Pollinators
Without pollinators, where would we be? By some estimates, 30 per cent of our food is made possible by the bees, beetles, flies, birds and butterflies that help grow our food — and let’s not forget honey! Honeybees produce honey from nectar and pollen collected from flowers. But now many pollinators get more than pollen and nectar when they visit blooms in our agricultural fields. In Canada, neonics have been found in the pollen and nectar of many crops.
Hundreds of studies show that the use of neonics causes pollinators like bees significant harm. It affects their ability to navigate, learn, collect food and reproduce. Bumble bee colonies permeated with neonics grow more slowly and produce fewer queens.
Not just agriculture
Are Neonics Worth It?
We have come to rely on insecticides like neonics for the control of pests on our food crops, garden flowers, tree farms and even the fleas on our dogs. We routinely apply these chemicals even before they are needed as insurance against a pest outbreak that may or may not occur. “It’s like taking antibiotics to avoid getting ill, before you are ill,” says biologist David Goulson, a scientist with the Task Force on Systemic Pesticides.
But is it worth it?
Widespread over-use of neonics is accelerating the rate at which insect pests all over the world are developing resistance. For example, just ten years after the neonic imidacloprid was introduced, 95 per cent of Colorado Potato Beetle populations in the Northeastern and Midwestern USA showed resistance. Yet despite increasing rates of pest resistance, many producers still consider neonics to be beneficial.
Neonics ≠ increased yield
And although neonics may appear to work in terms of reducing damage to the plant, in many cases this does not translate into higher yields at the end of the season. In one study, a neonic was found to reduce root injuries in corn, but this did not translate to a yield increase and associated economic benefit.
The questionable effectiveness of neonics and growing resistance of pest insects to these chemicals needs to be carefully weighed against the harm they are causing other organisms, and the loss of pollination and other services nature provides to agriculture.
Other Factors in Pollinator Decline
Insects are disappearing around the world. Recent estimates suggest that the current rate of decline may result in the extinction of 40 per cent of Earth’s insects over the next few decades. In Germany, for example, a 2017 analysis of 27 years of data found declines of 76 per cent of flying insects in protected areas. The authors of a 2018 study from Puerto Rico reported an insect decline of 98 per cent of ground foraging and 78 per cent of canopy dwelling arthropods (insects, arachnids and others with an exoskeleton) over 40 years. It’s thought that 40 per cent of invertebrate pollinators – especially butterflies and bees – are facing extinction. The International Union for Conservation of Nature Red List assessments indicate that 16.5 per cent of vertebrate pollinators are threatened with global extinction, increasing to 30 per cent for island species.
Habitat loss and conversion to intensive agriculture and urbanisation
It is now well-established that changes in food and nesting resources due to habitat loss results in lower densities and diversity of foraging insects. However, the situation can be improved through a return to sustainable agricultural systems. Where urban centres have expanded into natural habitat and swallowed up agricultural lands, the creation of pollinator pathways that include urban parklands and gardens can help bring pollinators back.
Biological factors (pathogens, parasites and invasive species)
Invasive alien species are those intentionally or accidentally introduced by humans beyond the species’ natural range. They quickly spread and grow in ways that impact other species and ecosystems. The results can be complex. For example, a generalist pollinator may benefit from an invasive plant that blooms frequently through the summer months. But if that invasive plant outcompetes a native plant relied upon by a pollinator specialist, the consequences could be disastrous. A recent review of the risks to pollinators from invasive species showed most interactions between native pollinators and invasive species are negative. While invasive plants can be a food source for pollinators, they can also transform pollinator diets, affecting their nutrition and posing risks for their health. Pollinating bees, for example, are very sensitive to the particular combination of nutrients found in the pollen of their preferred native plants. By feeding on invasive plants, pollinators may also be ignoring the pollination needs of native plants. Invasive pollinator species can spread pathogens and parasites to native pollinators (see above section). And some invasive species are predators of native pollinators. For example, the accidental introduction in 2004 of the predatory Yellow-legged Hornet into Europe from Asia directly threatens European Honey Bee populations.
We must work diligently in the coming years to create habitat that will ensure pollinators can overcome current threats. This will require not only the voice of our supporters but also significant investment into the work that lies ahead!
Governments within Canada have been slow to respond to this serious issue. We have to take action now; our precious wildlife is counting on us.
Your contribution today is critical to support all steps of our plan. This threat is not going away. The harmful effects of neonics will be seen decades from now and we can’t afford to lose any more time thinking about the issue.
For over 57 years, CWF has been dedicated to conserving wild species and spaces and with your help the future of Canada’s wildlife and habitat is in good hands.