Impact of Host Plant Resistance on the Tritrophic Interactions Between Wheat Genotypes,Schizaphis graminum(Homoptera: Aphididae), andCoccinella septempunctata(Coleoptera: Coccinellidae) Using Molecular Methods

Abstract

The objective of the current study was to evaluate the impact of wheat resistance on digestibility of Schizaphis graminum (Rondani) in the Coccinella septempunctata L. gut. Four wheat genotypes including an ancient wheat species (Einkorn) and three Iranian wheat genotypes (Azadi, Ommid, and Moghan2) were used. Einkorn was found to be a highly resistant species, while Azadi, Ommid, and Moghan2 were characterized as resistant, semiresistant, and susceptible genotypes, respectively, based on some biological parameters of S. graminum on these plants. Adult C. septempunctata starved for 24 h were fed one S. graminum reared on the selected wheat genotypes. A semiquantitative polymerase chain reaction technique using specific primers for the gene cytochrome oxidase II (COII) of S. graminum showed a significant effect of plant resistance on S. graminum DNA disappearance time. The DNA half-lives of S. graminum fed on Einkorn, Azadi, Ommid, and Moghan2 in C. septempunctata gut was 3.3, 3.6, 4.8, and 6.7 h, respectively. The findings suggest that digestibility of S. graminum fed on resistant plant genotypes is higher than those fed on susceptible plants because of the lighter weights and smaller sizes of the first. This phenomenon could result in faster ingestion of S. graminum by C. septempunctata on these resistant plants. It is also possible that some metabolites found differentially in Einkorn and Azadi genotypes may have affected S. graminum quality as a food for C. septempunctata.

Tri-trophic interaction involving host plants, black legume aphid, Aphis craccivora (Hemiptera: Aphididae) and the predator, Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

“…In contrast, because of the high nutritional quality of cowpea, aphids reared on this plant are large (Table 3 and 4) and both the larvae and adults of C. sexmaculata need to consume fewer aphids when on cowpea (Table 7). Similar fi ndings are reported by Barkhordar et al (2013). They studied the effect of host plant resistance in the tri-trophic interaction between wheat genotypes, the aphid, Schizaphis graminum, and the coccinellid beetle, Coccinella septempunctata.…”

Feeding preferences of Melanoplus femurrubrum grasshoppers on native and exotic grasses: behavioral and molecular approaches

“…For this reason, we intentionally used warm‐season grasses only which were morphologically and physiologically very similar; such grasses, even if they are not congenerics as suggested by Darwin's naturalization hypothesis, are still presumably similarly accessible for generalist grasshoppers, which apparently do not need to adapt to feed on these grasses, even if it is a novel food plant. Further exploration of grasshopper consumption of cutting leaf portions and digestibility of native and exotic plants with presumably different levels of plant resistance would allow us to better understand how clipping of leaves affects their digestibility in insects; specifically, a molecular approach to this question would be effective (Barkhordar et al., ).…”