Construction of a Modified Clip Cage and Its Effects on the Life-History Parameters of Sitobion avenae (Fabricius) and Defense Responses of Triticum aestivum

Clip cages are commonly used to confine aphids or other small insects to a single leaf when conducting plant-small insect interaction studies; however, clip cages are usually heavy or do not efficiently transmit light, which has an impact on leaf physiology, limiting their application. Here, simple, lightweight, and transparent modified clip cages were constructed using punched clear plastic cups, cut transparent polyvinyl chloride sheets, nylon organdy mesh, and bent duck-bill clips. These cages can be clipped directly onto dicot leaves or attached to monocot leaves with bamboo skewers and elastic bands. The weight, production time, and aphid escape rates of the modified clip cages were 3.895 ± 0.004 g, less than 3 min, and 2.154 ± 0.323%, respectively. The effects of the modified clip cage on the growth, development, and reproduction of the English grain aphid (Sitobion avenae Fabricius) in comparison with the whole cage were studied. The biochemical responses of wheat (Triticum aestivum) to the cages were also investigated. No significant differences were observed in the life table parameters, nymph mortality, and adult fecundity in S. avenae confined to clip cages and whole cages, but the clip cages were more time efficient than whole cages when conducting life table studies. Moreover, the hydrogen peroxide accumulation, callose deposition, and cell necrosis in wheat leaves covered by empty clip cages and empty whole cages were similar, and significantly lower than treatments where the aphids were inside the clip cage. The results demonstrate that the modified clip cages had negligible effects on the plant and aphid physiology, suggesting that they are effective for studying plant-small insect interactions.