Behaviour and Growth of Chironomus riparius Meigen (Diptera: Chironomidae) under Imidacloprid Pulse and Constant Exposure Scenarios

• Published in: Water, air, and soil pollution air, and soil pollution, 2011-07, Vol.219 (1-4), p.215-224
• Main Authors: Azevedo-Pereira, Henrique M. V. S., Lemos, Marco F. L., Soares, Amadeu M. V. M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Atmospheric Protection/Air Quality Control/Air Pollution; Behavioural; Bioassays; Biological and medical sciences; Chironomidae; Chironomus riparius; Climate Change/Climate Change Impacts; Diptera; Earth and Environmental Science; Ecotoxicology, biological effects of pollution; Environment; Environmental monitoring; Escape behavior; Exposure; Fundamental and applied biological sciences. Psychology; General aspects; Growth; Hydrogeology; Imidacloprid; Impairment; Indicator organisms; Insecta; Insecticides; Invertebrates; Laboratories; Larvae; Locomotion; Pesticides; Physiological aspects; Physiology; Pollution studies; Predators; Recovery; Soil pollution; Soil Science & Conservation; Toxicants; Toxicity; Water Quality/Water Pollution
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-010-0700-x

Imidacloprid is a new insecticide that mimics nicotine, combining its insecticidal activity with a reduced persistence in the environment. The toxicity of imidacloprid to Chironomus riparius Meigen using the formulated product Confidor® from Bayer®, in pulse and continuous exposure, was evaluated in this study. The behavioural response of the midge after toxicant exposure using an online biomonitor was also investigated. Early second-instar C. riparius larvae were exposed in either constant (10 days) or pulse (4 days, followed by 6 days post exposure in clean medium) conditions. Imidacloprid constant exposure resulted in a decrease in growth and impairment of the behavioural pattern of the midge larvae. Pulsed exposure followed by a recovery period revealed a recovery of midge physiological conditions, by reaching a stabilisation of normal behavioural activities and growth among treatments. Moreover, ventilation showed to be a more sensitive parameter by revealing a faster recovery than locomotion. Behaviour alterations may weaken the ability to escape from predators, and reduce food acquisition with consequent growth impairment. These effects may have an impact at the population and community level.