The susceptibility of a non target organism, the great egg-fly butterfly Hypolimnas bolina philippensis (Buttler) (Nymphalidae: Lepidoptera), to Bt corn pollen

Issue Date

10-2011

Abstract

The sustainable use of transgenic crops like Bt corn depends on various factors, one of which is the effect on non-target organisms (NTO's). Risk assessment involves a tiered approach. Tier 1 comprises laboratory studies on the effect of transgenic protein on the NTO's. A single high dose and dose response describes this scheme. Tier 2 is accomplished by refined hazard characterization and exposure assessment. This tier is affected only if the transgenic crop was found to be hazardous to NTO's at Tier 1. Tier 3 is realized through further refined risk assessment field experiments. Our previous study showed that the Cry 1Ab protein is not to the Great Egg Fly butterfly, Hypolimnas bolina philippinensis (Buttler) (Tier 1). Hence the study should be ended at this stage. Although this is the case, we conducted further study on this non-target organism to find out if indeed the Bt corn pollen has no effect on its growth and development (Tier 2). Three day-old H. bolina larvae were exposed on leaf of I. batatas Linnaeus dusted with Bt corn (MON 810) pollen. Controls were individually exposed on I. batatas leaves dusted with sweet corn (SG-75) pollen. There were 500-700 pollen grains per cm2 of the leaf. Fifty larvae each were used in treated and control experiments. Nine trials or 450 treated larvae and 450 non-treated larvae were done. The percentage mortality range for the treated group was 6-36% and a mean of 19.33%. The percentage mortality of range for the control was10-32% with a mean of 16.88%. The range of weight in grams of the treated group was 0.038-0.333% with a mean of 0.132 while the control group had 0.066-0.378 with mean of 0.145, respectively. The differences in mean mortality and mean weight of treated and control leaves using t-test with computed values of 0.494 and -0.322, respectively, were not statistically significant. The results showed that the Bt pollen was not toxic to H. bolina.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

25

Issue

2

Page

206

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

NYMPHALIDAE; LEPIDOPTERA; TRANSGENIC PLANTS; BACILLUS THURINGIENSIS; PEST RESISTANCE

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