Imidacloprid is a relatively new, systemic insecticide chemically related to the tobacco toxin nicotine. Like nicotine, it acts on the nervous system. Worldwide, it is considered to be one of the insecticides used in the largest volume. It has a wide diversity of uses: in agriculture, on turf, on pets, and for household pests. Symptoms of exposure to imidacloprid include apathy, labored breathing, incoordination, emaciation, and convulsions. Longer-term exposures cause reduced ability to gain weight and thyroid lesions. In studies of how imidacloprid affects reproduction, exposure of pregnant laboratory animals resulted in more frequent miscarriages and smaller offspring. An agricultural imidacloprid product increased the incidence of a kind of genetic damage called DNA adducts. Imidacloprid is acutely toxic to some bird species, including sparrows, quail, canaries, and pigeons. Partridges have been poisoned and killed by agricultural use of imidacloprid. It has also caused eggshell thinning. The growth and size of shrimp are affected by imidacloprid concentrations of less than one part per billion (ppb). Shrimp and crustaceans are killed by concentration of less than 60 ppb. Imidacloprid is persistent. In a field test in Minnesota, the concentration of imidacloprid did not decrease for a year following treatment. It is also mobile in soil, so is considered by the U.S. Environmental Protection Agency to be a potential water contaminant.

The development of resistance to imidacloprid by pest insects is a significant concern. In Michigan potato fields, the Colorado potato beetle developed resistance to imidacloprid after just two years of use.
Please follow this link for a full write up of this:
http://www.pesticide.org/imidacloprid.pdf
http://www.epa.gov/opprd001/factsheets/thiacloprid.pdf a newer stronger version of Imidacloprid.
http://edis.ifas.ufl.edu/PI117
http://www.bijensterfte.nl/nl/node/2
http://www.livingwithbugs.com/merit_insecticide.html
http://www.bioone.org/doi/abs/10.1603/0022-0493(2008)101%5B784:LASEOI%5D2.0.CO%3B2
http://www.coursehero.com/file/636383/imidacloprid/
http://nlquery.epa.gov/epasearch/epasearch?areaname=&areacontacts=http%3A%2F%2Fwww.epa.gov%2Fepahome%2Fcomments.htm&areasearchurl=&result_template=epafiles_default.xsl&action=filtersearch&filter=&typeofsearch=epa&querytext=imidacloprid Lots here to thumb thru, tho wirth the read. You can narrow your search as needed.