Editing Genetically modified maize (section)

=== Effects on nontarget insects ===
Critics claim that Bt proteins could target predatory and other beneficial or harmless insects as well as the targeted pest. These proteins have been used as organic sprays for insect control in France since 1938 and the USA since 1958 with no ill effects on the environment reported.<ref name="UC-history">{{cite web |url= http://www.bt.ucsd.edu/bt_history.html |title=History of Bt |publisher= University of California|access-date=8 February 2010}}</ref> While ''cyt'' proteins are toxic towards the insect order [[Diptera]] (flies), certain ''cry'' proteins selectively target [[lepidopterans]] (moths and butterflies), while other ''cyt'' selectively target [[Coleoptera]].<ref>{{Cite journal| vauthors = Al-Deeb MA, Wilde GE, Blair JM, Todd TC |title=Effect of Bt Corn for Corn Rootworm Control on Nontarget Soil Microarthropods and Nematodes|journal=Environmental Entomology|language=en-US|volume=32|issue=4|pages=859–865|doi=10.1603/0046-225x-32.4.859|year=2003|doi-access=free}}</ref> As a toxic mechanism, ''cry'' proteins bind to specific receptors on the membranes of mid-gut ([[epithelial]]) cells, resulting in rupture of those cells. Any organism that lacks the appropriate gut receptors cannot be affected by the ''cry'' protein, and therefore Bt.<ref>{{cite web |title=Bt corn: is it worth the risk?|url=http://www.scq.ubc.ca/bt-corn-is-it-worth-the-risk/| vauthors = Hall H |date=30 May 2006|publisher=The Science Creative Quarterly}}</ref><ref>{{cite journal | vauthors = Dorsch JA, Candas M, Griko NB, Maaty WS, Midboe EG, Vadlamudi RK, Bulla LA | title = Cry1A toxins of Bacillus thuringiensis bind specifically to a region adjacent to the membrane-proximal extracellular domain of BT-R(1) in Manduca sexta: involvement of a cadherin in the entomopathogenicity of Bacillus thuringiensis | journal = Insect Biochemistry and Molecular Biology | volume = 32 | issue = 9 | pages = 1025–36 | date = September 2002 | pmid = 12213239 | doi = 10.1016/s0965-1748(02)00040-1 }}</ref> Regulatory agencies assess the potential for the transgenic plant to impact nontarget organisms before approving commercial release.<ref>{{cite journal | vauthors = Romeis J, Hellmich RL, Candolfi MP, Carstens K, De Schrijver A, Gatehouse AM, Herman RA, Huesing JE, McLean MA, Raybould A, Shelton AM, Waggoner A | display-authors = 6 | title = Recommendations for the design of laboratory studies on non-target arthropods for risk assessment of genetically engineered plants | journal = Transgenic Research | volume = 20 | issue = 1 | pages = 1–22 | date = February 2011 | pmid = 20938806 | pmc = 3018611 | doi = 10.1007/s11248-010-9446-x }}</ref><ref>{{cite journal | vauthors = Romeis J, Bartsch D, Bigler F, Candolfi MP, Gielkens MM, Hartley SE, Hellmich RL, Huesing JE, Jepson PC, Layton R, Quemada H, Raybould A, Rose RI, Schiemann J, Sears MK, Shelton AM, Sweet J, Vaituzis Z, Wolt JD | display-authors = 6 | title = Assessment of risk of insect-resistant transgenic crops to nontarget arthropods | journal = Nature Biotechnology | volume = 26 | issue = 2 | pages = 203–8 | date = February 2008 | pmid = 18259178 | doi = 10.1038/nbt1381 | s2cid = 1159143 | url = https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1110&context=ent_pubs }}</ref>

A 1999 study found that in a lab environment, pollen from Bt maize dusted onto [[milkweed]] could harm the [[monarch butterfly]].<ref name="pmid10353241">{{cite journal | vauthors = Losey JE, Rayor LS, Carter ME | title = Transgenic pollen harms monarch larvae | journal = Nature | volume = 399 | issue = 6733 | pages = 214 | date = May 1999 | pmid = 10353241 | doi = 10.1038/20338 | bibcode = 1999Natur.399..214L | s2cid = 4424836 | doi-access = free }}</ref><ref>{{cite news | title=Engineered corn kills monarch butterflies | date=19 May 1999 | publisher=Cornell News | url=http://www.news.cornell.edu/releases/May99/Butterflies.bpf.html}}</ref> Several groups later studied the phenomenon in both the field and the laboratory, resulting in a [[risk assessment]] that concluded that any risk posed by the corn to butterfly populations under real-world conditions was negligible.<ref name="pmid11559842">{{cite journal | vauthors = Sears MK, Hellmich RL, Stanley-Horn DE, Oberhauser KS, Pleasants JM, Mattila HR, Siegfried BD, Dively GP | display-authors = 6 | title = Impact of Bt corn pollen on monarch butterfly populations: a risk assessment | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 98 | issue = 21 | pages = 11937–42 | date = October 2001 | pmid = 11559842 | pmc = 59819 | doi = 10.1073/pnas.211329998 | bibcode = 2001PNAS...9811937S | jstor = 3056827 | doi-access = free }}</ref> A 2002 review of the scientific literature concluded that "the commercial large-scale cultivation of current Bt–maize hybrids did not pose a significant risk to the monarch population".<ref name="pmid12047949">{{cite journal | vauthors = Gatehouse AM, Ferry N, Raemaekers RJ | title = The case of the monarch butterfly: a verdict is returned | journal = Trends in Genetics | volume = 18 | issue = 5 | pages = 249–51 | date = May 2002 | pmid = 12047949 | doi = 10.1016/S0168-9525(02)02664-1 }}</ref><ref>{{cite web|title=Monarch butterflies: A threat to individual caterpillars, but not to the population as a whole |date=Dec 2004 |publisher=GMO Safety |url=http://www.gmo-safety.eu/archive/237.monarch-butterflies-threat-individual-caterpillars-population-whole.html |url-status=dead |archive-url=https://web.archive.org/web/20110721173513/http://www.gmo-safety.eu/archive/237.monarch-butterflies-threat-individual-caterpillars-population-whole.html |archive-date=21 July 2011 }}</ref><ref>{{cite web| title=Butterflies and Bt Corn| work=United States Department of Agriculture| url=http://www.ars.usda.gov/sites/monarch/index.html| access-date=19 June 2005| archive-url=https://web.archive.org/web/20050318233043/http://www.ars.usda.gov/sites/monarch/index.html| archive-date=18 March 2005| url-status=dead}}</ref> A 2007 review found that "nontarget invertebrates are generally more abundant in Bt cotton and Bt maize fields than in nontransgenic fields managed with [[insecticide]]s. However, in comparison with insecticide-free control fields, certain nontarget taxa are less abundant in Bt fields."<ref>{{cite journal | vauthors = Marvier M, McCreedy C, Regetz J, Kareiva P | title = A meta-analysis of effects of Bt cotton and maize on nontarget invertebrates | journal = Science | volume = 316 | issue = 5830 | pages = 1475–7 | date = June 2007 | pmid = 17556584 | doi = 10.1126/science.1139208 | s2cid = 23172622 | bibcode = 2007Sci...316.1475M }}</ref>