A Comprehensive Assessment of the Effects of Transgenic Cry1Ac/Cry1Ab Rice Huahui 1 on Adult <i>Micraspis discolor</i> (Fabricius) (Coleoptera: Coccinellidae)

<div><p><i>Micraspis discolor</i> (Fabricius) (Coleoptera: Coccinellidae) is a widely distributed coleoptera predator in southern Asia in rice ecosystem, and adult <i>M</i>. <i>discolor</i> feed on both rice pollen and soft-bodied arthropods. Bitrophic bioassay and tritrophic bioassay were conducted to evaluate the potential impact of Cry1Ac/Cry1Ab-expressing rice Huahui 1 and its non-transgenic counterpart Minghui 63 on fitness parameters of adult <i>M</i>. <i>discolor</i>. The results showed that the survival, and fecundity of this beetle’ adults were not different when they fed on Bt rice or non-Bt rice pollen or <i>Nilaparvata lugens</i> (Stål) reared on <i>Bt</i> rice or non-<i>Bt</i> rice. Toxicity assessment to ensure <i>M</i>. <i>discolor</i> adults were not sensitive to Cry1Ab or Cry1Ac protein independent from the pollen background, <i>M</i>. <i>discolor</i> adults were fed with an artificial diet containing Cry1Ac, Cry1Ab or both protein approximately 10 times higher concentration than in Huahui 1 rice pollen. No difference was detected for any of the life-table parameters tested between Cry protein-containing and pure diet. Artificial diet containing E-64 (N-(trans-Epoxysuccinyl)-L-leucine 4-guanidinobutylamide) was included as a positive control. In contrast, the pre-oviposition and fecundity of <i>M</i>. <i>discolor</i> were significantly adversely affected by feeding on E-64-containing diet. In both bioassays, the uptakes of Cry protein by adult <i>M</i>. <i>discolor</i> were tested by ELISA measurements. These results indicated that adults of <i>M</i>. <i>discolor</i> are not affected by Cry1Ab- or Cry1Ac-expressing rice pollen and are not sensitive to Cry protein at concentrations exceeding the levels in rice pollen in Huahui1. This suggests that <i>M</i>. <i>discolor</i> adults would not be harmed by Cry1Ac/Cry1Ab rice if <i>Bt</i> rice Huahui 1 were commercialized.</p></div

Effect of feeding a pure artificial diet or artificial diet with purified Cry1Ab, Cry1Ac and E-64 provided on different life-table parameters of adult <i>Micraspis discolor</i>.

<p>Effect of feeding a pure artificial diet or artificial diet with purified Cry1Ab, Cry1Ac and E-64 provided on different life-table parameters of adult <i>Micraspis discolor</i>.</p

Different abundance of 3 predators in booting(I), tillering(II), early-blooming(III), blooming(IV) and filling(V) phases in Spring, Summer and Autumn rice seasons in 2013.

<p>Different abundance of 3 predators in booting(I), tillering(II), early-blooming(III), blooming(IV) and filling(V) phases in Spring, Summer and Autumn rice seasons in 2013.</p

Impact of the consumption of pollen from Cry1Ab /Cry1Ac-expressing <i>Bt</i> rice or the corresponding non-transformed rice plant on different life-table parameters of adult <i>Micraspis discolor</i>.

<p>Data are provided as mean (±SE).</p

Mean (±SE) daily fecundity of <i>Micraspis discolor</i> fed an artificial diet containing 150 mg/g Cry1Ab, 120 mg/g Cry1Ac, 150 mg/g Cry1Ab and 120 mg/g Cry1Ac or 25 mg/g E-64(positive control) per g dry weight of artificial diet.

<p>Pure artificial diet served as a negative control.</p

Impact of the consumption of BPH reared on Cry1Ab /Cry1Ac-expressing <i>Bt</i> rice or the corresponding non-transformed rice plants on different life-table parameters of adult <i>Micraspis discolor</i>.

<p>Data are provided as mean (±SE).</p