title: Interactive effects of elevated CO2 and cotton cultivar on tri-trophic interaction of Gossypium hirsutum, Aphis gossyppii, and Propylaea japonica.
abstract: Information on the effects of enriched CO2 on both the chemical composition of plants and the consequences of such changes for performance of a herbivore and its predator is an important first step in understanding the responses of plants and insects to global environmental change. We examined interactions across three trophic levels, cotton, Gossypium hirsutum, an aphid herbivore, Aphis gossypii Glover, and a coccinellid predator, Propylaea japonica (Thunberg), as affected by elevated CO2 concentrations and crop cultivars. Plant carbon:nitrogen (C:N) ratios, condensed tannin, and gossypol content were significantly higher, and nitrogen content was significantly lower in plants exposed to elevated CO2 levels compared with that in plants exposed to ambient CO2. Cotton aphid survivorship significantly increased and free fatty acid content decreased with increased CO2 concentrations. No significant differences in survival and lifetime fecundity of P. japonica were observed between cultivars and CO2 concentration treatments. However, stage-specific larval durations of the lady beetle were significantly longer when fed aphids from elevated CO2 concentrations. Our results indicate that high gossypol in the cotton host plant had an antibiotic effect on A. gossypii and produced a positive effect on growth and development of P. japonica at the third trophic level. However, elevated CO2 concentrations showed a negative effect on P. japonica. We speculate that A. gossypii may become a more serious pest under an environment with elevated CO2 concentrations because of increased survivorship of aphid and longer development time of lady beetle.
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: San-Rong
authors.initials: SR
authors.lastname: Zhu
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Du
authors.forename: Meghan
authors.initials: M
authors.lastname: Parajulee
authors.forename: Le
authors.initials: L
authors.lastname: Kang
authors.forename: Feng
authors.initials: F
authors.lastname: Ge
mesh_terms: D000818:Animals; D001042:Aphids / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D002244:Carbon / Q000032:analysis; D002245:Carbon Dioxide / Q000494:pharmacology*; D001517:Coleoptera / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D005230:Fatty Acids, Nonesterified / Q000032:analysis; D005260:Female; D005298:Fertility / Q000187:drug effects; D003368:Gossypium / Q000737:chemistry / Q000187:drug effects* / Q000469:parasitology; D006072:Gossypol / Q000032:analysis; D006790:Host-Parasite Interactions / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008136:Longevity / Q000187:drug effects; D008297:Male; D009584:Nitrogen / Q000032:analysis; D009758:Nymph / Q000187:drug effects / Q000254:growth & development; D044945:Proanthocyanidins / Q000032:analysis; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D005230:Fatty Acids, Nonesterified; D044945:Proanthocyanidins; D002245:Carbon Dioxide; D002244:Carbon; D006072:Gossypol; D009584:Nitrogen