Effects of Cd, Zn or Pb stress in Populus alba berolinensis on the development and reproduction of Lymantria dispar

Abstract

In order to investigate the effects of heavy metal stress on woody plant defense against phytophagous insects, we studied development and reproduction traits of the gypsy moth, Lymantria dispar that were separately fed with leaves plucked from poplar seedlings (Populus alba berolinensis) grown in either non-contaminated soil (control), Cd-contaminated soil (1.5 mg/kg), Zn-contaminated soil (500 mg/kg) or Pb-contaminated soil (500 mg/kg). The results showed that feeding on Cd or Pb stressed poplar leaves significantly decreased L. dispar larval weights, body lengths and head capsule widths, pupal weights and female fecundity, and delayed the duration of larval development. Similar effects from the Zn stressed poplar leaves were also observed on all the above mentioned variables except male pupal weight and larval development duration that showed no differences from the control. Cd, Zn, or Pb stressed poplar leaves had no significant effects on L. dispar larval survival, pupation and emergence rates; in fact, both larval survival and pupation rates reached 100%. These results suggest that Cd, Zn or Pb stress in P. alba berolinensis might help the trees defend against the defoliator, however; L. dispar may in turn have an effective detoxification mechanism for lessening the effects of plant-mediated defenses and heavy metals in leaves on larval survival, pupation and eclosion.

Bioaccumulation of Cadmium Affects Development, Mating Behavior, and Fecundity in the Asian Corn Borer, Ostrinia furnacalis

“…In the present study, the male pupal weight of O. furnacalis was significantly higher for Cd treatment than control treatment, but the female pupal weight displayed no effect under Cd stress. In contrast to our study, Jiang et al found that female/male pupal weights of Lymantria dispar (Coleoptera: Lymantriidae) were significantly decreased under Cd stress [43]. Similar reduction effects of Cd on body weight were reported in Blaps polycresta (Coleoptera: Tenebrionidae) [44].…”

The improved resistance against gypsy moth in Larix olgensis seedlings exposed to Cd stress association with elemental and chemical defenses

“…TI and CI are two small molecular proteins or peptides closely related to the resistance of various plants against insects, which can form enzyme inhibitor complexes with protein digestive enzymes in the digestive tracts of herbivores, and reduce the ability of herbivores to digest proteins in food materials . As demonstrated in our previous studies, protease inhibitors in Populus alba × P. berolinensis seedlings can positively respond to heavy metal stress in an external environment . In the present study, we found that Cd stress at a high concentration (4 mg kg −1 ) significantly decreased the TI and CI activities in the needles of L. olgensis seedlings compared to the untreated control or treated groups with 1 and 2 mg kg −1 Cd, and that CI and TI activities were activated to varying degrees at low and moderate Cd concentrations.…”

“…46,47 As demonstrated in our previous studies, protease inhibitors in Populus alba × P. berolinensis seedlings can positively respond to heavy metal stress in an external environment. 17,47 In the present study, we found that Cd stress at a high concentration (4 mg kg −1 ) significantly decreased wileyonlinelibrary.com/journal/ps the TI and CI activities in the needles of L. olgensis seedlings compared to the untreated control or treated groups with 1 and 2 mg kg −1 Cd, and that CI and TI activities were activated to varying degrees at low and moderate Cd concentrations. These data suggested that apart from varying with heavy metal species investigated and exposure duration, the response trends of protease inhibitors in plants to heavy metal stress might depend on the exposure concentration.…”

“…For example, according to optimal defense theory, when the losses caused by plant diseases and insects recovered by production of chemical defense substances exceed the gains from their own growth and development, a large number of resources in plant will be used to synthesize defense‐related substances, thus indirectly improving their chemical defense capabilities. Mounting evidence indicates that biotic stimuli, abiotic stimuli and resource allocation can not only directly drive plant chemical defense, but also interact with each other to regulate plant defense against herbivores . Therefore, heavy metal stress, as an abiotic stimulus, at a moderate concentration may induce large amounts of secondary metabolites in plants, which can be used to improve the phytochemical defense.…”

“…Mounting evidence indicates that biotic stimuli, abiotic stimuli and resource allocation can not only directly drive plant chemical defense, but also interact with each other to regulate plant defense against herbivores. 16,17 Therefore, heavy metal stress, as an abiotic stimulus, at a moderate concentration may induce large amounts of secondary metabolites in plants, which can be used to improve the phytochemical defense.…”