title: Inhibitional effects of metal Zn²⁺ on the reproduction of Aphis medicaginis and its predation by Harmonia axyridis.
abstract: BACKGROUND
  Contamination, including metals, can disturb the reproductive processes of many organisms, including both prey and predatory insects. However, there is virtually no information on the effects of high level Zinc (Zn) pollution on aphids and ladybirds. The high concentrations of Zn²⁺ or Zn pollution inhibit reproduction in the phytophagous aphid, Aphis medicaginis, and the predatory ladybird Harmonia axyridis could provide important information.
  
  
  RESULTS
  It was observed in this study that Zn concentrations in Vicia faba (broad bean) seeds and seedlings in all Zn²⁺ treatments were significantly higher than that in the control group, and increased with increasing Zn²⁺ concentrations in the solution. The rate of reproduction in A. medicaginis declined significantly (p<0.05) over time in the five groups fed on broad bean seedlings treated with different concentrations of Zn²⁺ solution compared with the control group. These results showed that higher concentrations of Zn²⁺ significantly inhibited the reproductive capacity of A. medicaginis. We also cloned and identified a gene encoding vitellogenin (Vg) from A. medicaginis, which has an important role in vitellogenesis, and therefore, reproduction was affected by exposure to Zn²⁺. Expression of AmVg was reduced with increasing exposure to Zn²⁺ and also in the F1-F3 generations of aphids exposed to different Zn²⁺ concentrations. Predation by H. axyridis was also reduced in aphids exposed to high-levels of Zn²⁺. Similarly, ovipositioning by H. axyridis was also reduced.
  
  
  CONCLUSIONS
  Our results suggest that Zn²⁺ can significantly affect the reproductive capacity of both A. medicaginis and its predator H. axyridis, the former through effects on the expression of AmVg and the latter through avoidance of aphids containing high levels of Zn²⁺.
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Xie
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Jiaping
authors.initials: J
authors.lastname: Zou
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Mengjing
authors.initials: M
authors.lastname: Wu
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Shigui
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Hangzhou Key Laboratory of Animal Adaptation and Evolution, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China ; Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Tang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000502:physiology; D001483:Base Sequence; D003001:Cloning, Molecular; D001517:Coleoptera / Q000187:drug effects* / Q000502:physiology; D004785:Environmental Pollutants; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008969:Molecular Sequence Data; D010802:Phylogeny; D011235:Predatory Behavior; D036226:Seedlings / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D031306:Vicia / Q000737:chemistry; D014819:Vitellogenins / Q000235:genetics; D015032:Zinc / Q000009:adverse effects* / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D014819:Vitellogenins; D015032:Zinc