Agricultural Activities and Pesticides

Science Center Objects

Agriculture plays an important role in our economy and many kinds of chemicals are used for the production, transportation, storage, and manufacturing of food. Agricultural areas attract a variety of wildlife and our scientists provide the needed research to understand potential hazards to wildlife from these agricultural chemicals and how unintentionally exposed animals may be affected. 

Neonicotinoid pesticides act as agonists of nicotinic acetylcholine receptors

Imidacloprid binds the nicotinic acetylcholine receptor causing excitatory neurotransmission in the central and peripheral nervous systems. (Public domain.)

 

 

Genomic and Behavioral Effects of the Neonicotinoid Imidacloprid in Birds Exposed Through Pesticide-Coated Seeds

Neonicotinoid pesticides act as agonists of nicotinic acetylcholine receptors (nAChRs) and are designed to be lethal to insects while theoretically posing little to no threat to vertebrates. The perceived safety of neonicotinoids has led to a sharp increase in their use in the United States and globally, since they were first introduced in 1994. The use of the neonicotinoid imidacloprid in the United States has increased 166% since 2009, from 0.75 to roughly 2 million pounds, and its use as seed treatment represents approximately 56% of total annual usage. Although neonicotinoids are designed to be selectively toxic to invertebrates, effects on other organisms are being reported. However, toxicity information on birds is particularly limited. Birds are primarily exposed to neonicotinoids orally (feeding, preening), by inhalation, or dermally depending on whether the pesticide is applied by aerial spraying or as a seed coating.

 

 

Dye deposition in yolk over time

Dye deposition in yolk over time (Public domain.)

 

 

 

Assessing Toxicogenomics Effects of a Synthetic Androgen on Japanese Quail and the Development of an Avian Vitellogenesis Model

Endocrine active chemicals (EAC) are known to interfere with hormonally regulated physiological processes, thereby affecting signaling in the hypothalamic-pituitary-gonadal-liver (HPGL) axis and commonly resulting in reproductive dysfunction. Computational models that relate hormonal and genomic biomarkers within the HPGL axis to the reproductive cycle and ecologically relevant endpoints have been developed for fish; however, no similar model is available for birds. These models are very useful for evaluating how EAC-induced changes in physiological systems enhance or inhibit embryonic development, reproduction, and growth.

 

Subadult Japanese quail

Subadult Japanese quail, Coturnix japonica (Public domain.)

 

 

The Role of Japanese Quail in Ecotoxicology

Wild birds are exposed throughout their lives to natural and synthetic chemicals that are present in the environment, many of which interfere with the animal’s physiological and developmental systems. Relative concentrations, routes, frequency, and the environment in which chemical exposure occurs will determine to a large extent the bird’s response. Well-designed avian field studies conducted on site are expensive, both in terms of personnel and funding. In order to address specific field exposures and/or focus on variables of particular concern, pen studies can be conducted on a smaller scale. The Japanese quail (Coturnix japonica, JQ) has been used as a model for gallinaceous birds in research because it exhibits a short generation time of 53-74 days and all stages of its development can be maintained and tested in captivity under controlled laboratory pen conditions. As we move towards minimizing the numbers of animals used for research, the role of the JQ as an appropriate model for avian wildlife in ecotoxicological studies is being redefined.

 

Radiograph illustrating soy bean seeds in crop and gastrointestinal tract

Radiograph illustrating soy bean seeds (Public domain.)

 

 

 

 

Do Neonicotinoid Pesticide Seed Coatings Pose a Hazard to Seed-eating Birds?

Neonicotinoids are now the most widely applied class of insecticides in the United States, and are predominantly used in the form of seed treatments. Compared to invertebrates, neonicotinoids are less toxic to wildlife, although genotoxic, cytotoxic, immunological, behavioral and reproductive effects have been reported in studies with birds. At present, little is known about the pharmacokinetics (absorption, distribution, metabolism and excretion) of these pesticides in birds, which can dictate and affect the timecourse of their toxicity. Such information will greatly assist in evaluating the hazard and risk of neonicotinoid seed coatings to wild birds.