Impact of transgenic cotton plants on a non‐target pest, Aphis gossypii Glover

Abstract

Abstract. 1. Transgenic crops have shown great promise for the control of target pest insects, but in some cases they can also influence non‐target species. This study investigated the impact of Bt and Bt+CpTI transgenic cottons on the non‐target cotton aphid, Aphis gossypii Glover, by comparing life‐table parameters, feeding behaviour, and the fluctuating asymmetry of morphological traits of aphids reared on transgenic cotton and those on untransformed control plants.2. Aphids on the Bt+CpTI cotton showed a shorter reproductive duration and maximum lifespan, lower survival rates and potential maximum fecundity, and an earlier occurrence of peak daily mortality in the first or second generation. However, the aphid population soon developed fitness and overcame the negative effect in the second or third generation. The aphids on the Bt cotton had significantly longer reproductive durations in the first generation, higher survival rates in the third generation, and apparently larger potential maximum fecundity in all three generations.3. The percentages of accumulated duration of feeding waveforms E1 and E2 were significantly lower in aphids on the Bt+CpTI cotton than in those on the Bt or control cotton, whereas the frequencies of moving and finding feeding sites, and probe behaviour were significantly higher.4. Fluctuating asymmetry in three morphological characters of aphids reared on transgenic and control cotton was detected. The fluctuating asymmetry value of the third segment of antenna in aphids on Bt+CpTI cotton was significantly higher than that of aphids on Bt or control cotton. Based on the fluctuating asymmetry value, the stress of cotton on the aphids could be ranked as Bt+CpTI cotton > Bt cotton > control cotton.

Temporal allocation of metabolic tolerance to transgenic Bt cotton in beet armyworm, Spodoptera exigua (Hübner)

“…Liu et al [29] reported that larval growth of the cotton bollworm, Helicoverpa armigera (Hübner), was prolonged and its pupation rate and pupal weight decreased when fed on a diet containing Cry1Ac toxin. Liu et al [30] reported that aphids fed on transgenic Bt+CpTI cotton had a shorter reproduction period, longer lifespan, lower survival rate, and earlier occurrence of peak daily mortality in the first or second generation when compared with those fed on non-transgenic cotton.…”

Interactions betweenBt-expressing tomato and non-target insects: the aphidMacrosiphum euphorbiaeand its natural enemies

“…In a multigeneration study, A. gossypii performed better on Cry1A-expressing cotton than on untransformed controls with a visible impact on morphological traits (Liu et al 2005). Similarly, R. padi performed better on Bt-maize in terms of fecundity with respect to control plants, though no final effect on r m was recorded (Lumbierres et al 2004).…”

“…The possible effects of Bt toxins on organisms at higher trophic levels delivered via GM plants and aphids have been described in several plantÁCry toxin systems, but the results are sometimes contrasting (Head et al 2001;Raps et al 2001;Dutton et al 2002;Lumbierres et al 2004;Liu et al 2005;Burgio et al 2007;Ramirez-Romero et al 2008;Zhang et al 2008).…”

Genetically engineered (modified) crops (Bacillus thuringiensis crops) and the world controversy on their safety

“…Similarly, the continuous cultivation of Bt cotton caused obvious infestation by aphids and mealybugs in India (Losey et al 1999). Laboratory tests conducted by Liu et al (2005) showed that Aphid gossypii fed on Bt cotton had shorter reproductive duration, maximum lifespan, and an earlier peak of daily mortality in the 1st and 2nd generations compared to individuals fed on non-Bt cotton.…”