Simplification effect of lead soil contamination on the structure and function of a food web of plant-associated insects

Changes in the Biology and Susceptibility of Weevil (Cylas formicarius) to the Insecticide Spinetoram as a Response to Cadmium Contamination

“…Nonessential heavy metals, such as cadmium (Cd), mercury (Hg), lead (Pb), nickel (Ni), and copper (Cu), are highly reactive and toxic at low concentrations, posing severe risks to many organisms, including plants and insects [ 2 , 3 ]. Heavy metal pollution is distributed globally because of human production activities, including mining, smelting, sewage discharge, and use of metal-containing pesticides and fertilizers [ 4 , 5 , 6 ]. It is estimated that the annual global emissions of Cd, Pb, and Cu reach approximately 1.0 × 10 6 tons, 5.0 × 10 6 tons, and 3.4 × 10 6 tons, respectively [ 7 ].…”

“…In soil–plant–insect systems, heavy metal accumulations in soil and plants affect both plants and insects. The effects of heavy metals have been examined in a variety of plants (e.g., rice, maize, soybean, kale), as well as in coleopteran, hemipteran, dipteran, lepidopteran, and orthopteran insects [ 3 , 6 , 15 , 16 , 17 , 18 , 19 , 20 ]. Among hypotheses to explain metal hyperaccumulation in plants, the elemental defense hypothesis is the most widely tested, and it proposes that metals accumulate in plant tissues to defend against insect herbivory [ 3 , 21 , 22 , 23 , 24 ].…”

“…According to Jiang et al [ 26 ], Cd stress increased the resistance of larch ( Larix olgensis ) seedlings to gypsy moth, with decreases in gypsy moth body weight and detoxification mechanisms associated with changes in contents or activities of protease inhibitors, tannins, and phenolic acids in L. olgensis seedling needles. For insects, heavy metals can be transferred to herbivorous insects through food chains, causing chronic toxicological effects on growth and physiology [ 27 ], altering behavior [ 28 ], and simplifying the community of plant-associated insects [ 6 , 29 ]. After an initial taste of metal-rich plant materials, the desert locust Schistocerca gregaria develops an aversion and decreases ingestion rates [ 30 ], whereas the grass miner Chromatomyia milii reduces feeding and oviposition on heavy metal-exposed plants [ 31 ].…”