Field deposition of Bt transgenic corn pollen: lethal effects on the monarch butterfly

Abstract

We present the first evidence that transgenic Bacillus thuringiensis (Bt) corn pollen naturally deposited on Asclepias syriaca; common milkweed, in a corn field causes significant mortality of Danaus plexippus L. (Lepidoptera: Danaidae) larvae. Larvae feeding for 48 h on A. syriaca plants naturally dusted with pollen from Bt corn plants suffered significantly higher rates of mortality at 48 h (20±3%) compared to larvae feeding on leaves with no pollen (3±3%), or feeding on leaves with non-Bt pollen (0%). Mortality at 120 h of D. plexippus larvae exposed to 135 pollen grains/cm(2) of transgenic pollen for 48 h ranged from 37 to 70%. We found no sub-lethal effects on D. plexippus adults reared from larvae that survived a 48-h exposure to three concentrations of Bt pollen. Based on our quantification of the wind dispersal of this pollen beyond the edges of agricultural fields, we predict that the effects of transgenic pollen on D. plexippus may be observed at least 10 m from transgenic field borders. However, the highest larval mortality will likely occur on A. syriaca plants in corn fields or within 3 m of the edge of a transgenic corn field. We conclude that the ecological effects of transgenic insecticidal crops need to be evaluated more fully before they are planted over extensive areas.

Effects of exposure to event 176 Bacillus thuringiensis corn pollen on monarch and black swallowtail caterpillars under field conditions

“…Despite the high variation in pollen densities from sample to sample, patterns of pollen distribution observed in this study (Fig. 1) were consistent with those previously reported (6,7,9), in that the greatest amounts of pollen were deposited in close proximity to the cornfield.…”

“…Also unresolved are the long-term consequences of larval mass reduction over the life of the caterpillar. Hansen-Jesse and Obrycki (6) suggest that age may influence susceptibility of monarch larvae to pollen ingestion. Moreover, because the greatest amount of all food ingested over the course of caterpillar development is consumed in the ultimate instar, caterpillars experiencing developmental delays early in life may be able to compensate if they subsequently consume uncontaminated foliage.…”

Monitoring the impact ofBtmaize on butterflies in the field: estimation of required sample sizes

“…As the Bt toxin is specifically active on lepidopteran species, the impact on non-target organisms has been considered negligible. However, concerns have been raised that Bt maize may affect Lepidoptera other than pest species as well (Felke et al, 2002;Hansen Jesse and Obrycki, 2000;Losey et al, 1999). Most commercial Bt maize hybrids express the toxin also in the pollen, which may then be deposited on host plants of lepidopteran larvae occurring in field margins close to maize fields (Pleasants et al, 2001).…”

“…Most commercial Bt maize hybrids express the toxin also in the pollen, which may then be deposited on host plants of lepidopteran larvae occurring in field margins close to maize fields (Pleasants et al, 2001). So far, lethal and negative sub-lethal effects of Bt maize pollen consumption for larvae were demonstrated for a variety of butterfly species in the laboratory, the absolute effect depending on the particular maize event, the amount of pollen consumption, the lepidopteran species, the instar of the larvae and other factors (Felke and Langenbruch, 2001;Felke et al, 2002;Hansen Jesse and Obrycki, 2000;Hellmich et al, 2001;Losey et al, 1999). Field experiments published to date have confirmed possible adverse effects of the Bt maize event 176 on some butterfly larvae, while event 810 seems to be much less toxic Wraight et al, 2000;Zangerl et al, 2001).…”

Establishment of Dipstick Development Technology for Detection of Cry1Ac in Transgenic Plants

“…Recently, Dong et al have developed a database "GMO Detection method Database (GMDD)"which placid almost all the earlier developed and conveyed GMOs detection methods. The frequently used DNA based methods include polymerase chain reaction (PCR) and real-time PCR, while protein based methods include immuno PCR, near infrared (NIR) spectroscopy, micro fabricated devices, chromatography mass spectrophotometry and DNA chip technology which offer solutions to current technical issues in GM crop analysis [7], but these methods are costly, time taking and advantages along with the disadvantages [8]. Other protein based methods include enzyme linked immunosorbent assay (ELISA) and western blot.…”