Neonicotinoid insecticides cause rapid weight loss and travel delays in migrating songbirds

September 12, 2019

Songbirds exposed to imidacloprid, a widely used neonicotinoid insecticide, exhibit anorexic behavior, reduced body weight and delays in their migratory itinerary, according to a new study. This is perhaps the first direct evidence of a mechanistic link between the pesticide and declining migratory bird populations. The results suggest that, even in tiny sublethal doses, the presence of these neurotoxic compounds at critical stopover sites refueling birds visit on their cross-continental springtime journeys could be contributing to the overall population declines observed among many migratory species. Neonicotinoids are the most widely used class of agricultural pesticide. However, while the controversial neurotoxic insecticide is advertised to pose a low risk to vertebrates, a growing body of evidence has shown that neonicotinoids may have significant negative impacts on a number of species, including birds. This research has suggested that birds who use agricultural environments as habitats or for foraging stopovers during migration are routinely exposed to neonicotinoid pesticides. Many of these species are also undergoing precipitous population declines. Despite this association, the overall influence of neonicotinoids on wild migratory songbirds remains virtually unknown. Building on previous research, Margaret Eng and colleagues used automated telemetry to track individual white-crowned sparrows they experimentally exposed to sublethal yet field-realistic doses of imidacloprid during migration. The authors found that the pesticide acted as an anorexic agent within the birds, causing rapid losses in body weight and fat. This resulted in extended stays at stopover sites as the birds had to forage longer to restore their greatly depleted fuel stores and to recover from imidacloprid's neurotoxic effects before moving on. According to Eng et al., the use of neonicotinoids along migratory routes throughout North America means that birds may suffer repeated exposure at successive stopover sites, amplifying migration delays and their consequences.

American Association for the Advancement of Science

Related Pesticide Articles from Brightsurf:

Pesticide deadly to bees now easily detected in honey
A common insecticide that is a major hazard for honeybees is now effectively detected in honey thanks to a simple new method.

Pesticide mixtures a bigger problem than previously thought
New research led by The University of Queensland has provided the first comprehensive analysis of pesticide mixtures in creeks and rivers discharging to the Great Barrier Reef.

Pesticide seed coatings are widespread but underreported
Seed-coated pesticides -- such as neonicotinoids, many of which are highly toxic to both pest and beneficial insects -- are increasingly used in the major field crops, but are underreported, in part, because farmers often do not know what pesticides are on their seeds, according to an international team of researchers.

Pesticide companies leverage regulations for financial gains
Some pesticide companies may put profit ahead of protecting the public from potential harms.

Pesticide exposure may increase heart disease and stroke risk
Occupational exposure to high levels of pesticides may raise the risk of heart disease and stroke, even in generally healthy men.

Biting backfire: Some mosquitoes actually benefit from pesticide application
The common perception that pesticides reduce or eliminate target insect species may not always hold.

Transfer of EU powers leads to silent erosion of UK pesticide regulation
New analysis by the UK Trade Policy Observatory is warning of a significant weakening of enforcement arrangements covering the approval of pesticides as part of legislative changes carried out under the EU Withdrawal Act.

Pesticide exposure causes bumblebee flight to fall short
Bees exposed to a neonicotinoid pesticide fly only a third of the distance that unexposed bees are able to achieve.

Tomato, tomat-oh! -- understanding evolution to reduce pesticide use
Although pesticides are a standard part of crop production, Michigan State University researchers believe pesticide use could be reduced by taking cues from wild plants.

Pesticide cocktail can harm honey bees
A series of tests conducted over several years by scientists at UC San Diego have shown for the first time that Sivanto, developed by Bayer CropScience AG and first registered for commercial use in 2014, could pose a range of threats to honey bees depending on seasonality, bee age and use in combination with common chemicals such as fungicides.

Read More: Pesticide News and Pesticide Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to