title: Specificity of extrafloral nectar induction by herbivores differs among native and invasive populations of tallow tree.
abstract: OBJECTIVE
  Invasive plants can be released from specialist herbivores and encounter novel generalists in their introduced ranges, leading to variation in defence among native and invasive populations. However, few studies have examined how constitutive and induced indirect defences change during plant invasion, especially during the juvenile stage.
  
  
  METHODS
  Constitutive extrafloral nectar (EFN) production of native and invasive populations of juvenile tallow tree (Triadica sebifera) were compared, and leaf clipping, and damage by a native specialist (Noctuid) and two native generalist caterpillars (Noctuid and Limacodid) were used to examine inducible EFN production.
  
  
  RESULTS
  Plants from introduced populations had more leaves producing constitutive EFN than did native populations, but the content of soluble solids of EFN did not differ. Herbivores induced EFN production more than simulated herbivory. The specialist (Noctuid) induced more EFN than either generalist for native populations. The content of soluble solids in EFN was higher (2·1 times), with the specialist vs. the generalists causing the stronger response for native populations, but the specialist response was always comparable with the generalist responses for invasive populations.
  
  
  CONCLUSIONS
  These results suggest that constitutive and induced indirect defences are retained in juvenile plants of invasive populations even during plant establishment, perhaps due to generalist herbivory in the introduced range. However, responses specific to a specialist herbivore may be reduced in the introduced range where specialists are absent. This decreased defence may benefit specialist insects that are introduced for classical biological control of invasive plants.
authors.affiliation: Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Institute/Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Juli
authors.initials: J
authors.lastname: Carrillo
authors.forename: Evan
authors.initials: E
authors.lastname: Siemann
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Wheeler
authors.forename: Lin
authors.initials: L
authors.lastname: Zhu
authors.forename: Xue
authors.initials: X
authors.lastname: Gu
authors.forename: Jianqing
authors.initials: J
authors.lastname: Ding
mesh_terms: D000818:Animals; D019665:Euphorbiaceae / Q000502:physiology*; D060434:Herbivory; D058865:Introduced Species; D009036:Moths / Q000502:physiology*; D057048:Plant Nectar
chemical_list: D057048:Plant Nectar
keywords: Constitutive and inducible defences; EFN; Limacodidae; Noctuidae; Triadica sebifera; caterpillars; extrafloral nectar; generalists; invasion ecology; juvenile plants; specialists; tallow tree