Multi-Generation Effects of Bt Rice on Anagrus nilaparvatae, a Parasitoid of the Nontarget Pest Nilapavarta lugens

Abstract

Little is known about the potential cumulative long-term effects of transgenic crops on nontarget organisms. In the present laboratory study, the potential cumulative effects of transgenic Bacillus thuringiensis (Bt) rice on parasitoids in successive generations were observed for an egg parasitoid, Anagrus nilaparvatae parasitizing eggs of Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) feeding on Bt rice. Enzyme-linked immunosorbent assay test confirmed that Cry1Ab insecticidal protein could be detected in newly eclosed parasitoid adults. However, no significant effect on the fecundity of Anagrus nilaparvatae Pang et Wang (Hymenoptera: Mymaridae) was observed between Bt and non-Bt rice. Developmental times of both genders of A. nilaparvatae parasitizing host eggs laid in Bt (KMD1 and KMD2) rice lines were significantly prolonged from first generation to second generation, but not always prolonged from third generation to 11th generation as compared with the control rice line. Furthermore, the sex ratio of A. nilaparvatae progeny from the first generation to 11th generation in three rice lines was not significantly different. In general, our results suggested that the effect of Bt rice on this parasitoid could be negligible.

Presence of Cry1Ab in the Bt maize – aphid (Rhopalosiphum maidis) – ladybeetle (Propylea japonica) system has no adverse effects on insect biological parameters

“…These results are inconsistent with some studies that reported that natural enemy species can uptake and even bio-accumulate Cry toxins delivered by their prey (Couty et al, 2001;Bernal et al, 2002;Zhang et al, 2006a;Gao et al, 2010;Paula & Andow, 2016), as Cry1Ab concentrations in corresponding aphids were still detectable at low levels. The Cry1Ab concentrations in P. japonica agreed with the results of Cry1Ab concentrations in aphids and feeding amounts for the 5422Bt1 and 5422CBCL treatments.…”

Farm‐scale evaluation of the impact of Cry1Ab Bt maize on canopy nontarget arthropods: a 3‐year study

“…Thus, exposure to Cry toxins in the field has been reported in predators belonging to different taxa, such as Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae), Orius majusculus (Reuter) (Hemiptera: Anthocoridae) or Stethorus punctillum Weise (Coleoptera: Coccinellidae) (Harwood et al ., ; Obrist et al ., ; Álvarez‐Alfageme et al ., ). The exposure of parasitoids to the toxin has been only demonstrated under laboratory conditions in Anagrus nilaparvatae Pang et Wang (Hymenoptera: Mymaridae) when parasitizing eggs of Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) feeding on Bt rice (Gao et al ., ).…”

Limitations in dose–response and surrogate species methodologies for risk assessment of Cry toxins on arthropod natural enemies

“…In the last 15 years, laboratory studies have demonstrated that some natural enemy species can uptake and even bioaccumulate Cry toxins delivered from their prey (Couty et al 2001;Zhang et al 2006;Gao et al 2010;Paula and Andow 2015). Uptake is the absorption of a chemical from the food (USEPA 2013), i.e.…”