Tri-Trophic Impacts of Bt-Transgenic Maize on Parasitoid Size and Fluctuating Asymmetry in Native vs. Novel Host-Parasitoid Interactions in East Africa
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Insects
Abstract
Environmental stress can affect trait size and cause an increase in the fluctuating asymmetry
(FA) of bilateral morphological traits in many animals. For insect parasitoids, feeding of hosts on
transgenic maize, expressing a Bacillus thuringiensis toxin gene is a potential environmental stressor.
We compared the size of antennae, forewings, and tibia, as well as their FA values, in two parasitoids
developed on two East African host species feeding on non-transgenic vs. transgenic maize. The two
lepidopteran stem-borer hosts were the native Sesamia calamistis Hampson (Lepidoptera: Noctuidae)
and a recent invader, Chilo partellus Swinhoe (Lepidoptera: Crambidae). The two braconid parasitoids
were the native, gregarious larval endoparasitoid Cotesia sesamiae and the recently introduced
Cotesia flavipes. Both parasitoids attacked both hosts, creating evolutionarily old vs. novel interactions.
Transient feeding of hosts on transgenic maize had various effects on FA, depending on trait as
well as the host and parasitoid species. These effects were usually stronger in evolutionarily novel
host–parasitoid associations than in the older, native ones. These parameters have capacity to more
sensitively indicate the effects of potential stressors and merit further consideration.
Description
Keywords
GM plants, Biosafety, Natural enemies, Morphological traits, Environmental stress, Stem borers, Ecosystem services
Citation
Ndolo, D. O., Songa, J. M., & Lövei, G. L. (2018). Tri-Trophic Impacts of Bt-Transgenic Maize on Parasitoid Size and Fluctuating Asymmetry in Native vs. Novel Host-Parasitoid Interactions in East Africa. Insects, 9(2), 38. doi:10.3390/insects9020038