Biological Invasions

, Volume 12, Issue 8, pp 2797–2813

Temporal and spatial variations in the parasitoid complex of the horse chestnut leafminer during its invasion of Europe

Authors

    • BOKU Vienna, Institute of Plant Protection
    • AGES Vienna
  • Patrik Kehrli
    • UNI Bern, Institute of Zoology
    • Service Entomologie, Station de Recherche Agroscope Changins-Wädenswil
  • Irene Zweimüller
    • Faculty of Life SciencesUniversity of Vienna
  • Sylvie Augustin
    • INRA Orleans, UR633 Zoologie Forestière
  • Nikolaos Avtzis
    • Department of ForestryTEI Kavala
  • Sven Bacher
    • UNI Bern, Institute of Zoology
    • UNI Fribourg, Department of Biology
  • Jona Freise
    • Department of Animal EcologyTU Munich
    • LAVES Niedersachsen
  • Sandrine Girardoz
    • CABI Europe-Switzerland
  • Sylvain Guichard
    • INRA Orleans, UR633 Zoologie Forestière
  • Werner Heitland
    • Department of Animal EcologyTU Munich
  • Christa Lethmayer
    • AGES Vienna
  • Michaela Stolz
    • BOKU Vienna, Institute of Plant Protection
  • Rumen Tomov
    • Faculty of AgronomyUniversity of Forestry
  • Lubomir Volter
    • Institute of EntomologyBiology Centre of the Academy of Sciences
  • Marc Kenis
    • CABI Europe-Switzerland
Original Paper

DOI: 10.1007/s10530-009-9685-z

Cite this article as:
Grabenweger, G., Kehrli, P., Zweimüller, I. et al. Biol Invasions (2010) 12: 2797. doi:10.1007/s10530-009-9685-z

Abstract

The enemy release hypothesis posits that the initial success of invasive species depends on the scarcity and poor adaptation of native natural enemies such as predators and parasitoids. As for parasitoids, invading hosts are first attacked at low rates by a species-poor complex of mainly generalist species. Over the years, however, parasitoid richness may increase either because the invading host continuously encounters new parasitoid species during its spread (geographic spread-hypothesis) or because local parasitoids need different periods of time to adapt to the novel host (adjustment-hypothesis). Both scenarios should result in a continuous increase of parasitoid richness over time. In this study, we reconstructed the development of the hymenopteran parasitoid complex of the invasive leafminer Cameraria ohridella (Lepidoptera, Gracillariidae). Our results show that the overall parasitism rate increases as a function of host residence time as well as geographic and climatic factors, altogether reflecting the historic spread of C. ohridella. The same variables also explain the individual parasitism rates of several species in the parasitoid complex, but fail to explain the abundance of others. Evidence supporting the “geographic spread-hypothesis” was found in the parasitism pattern of Cirrospilus talitzkii (Hymenoptera, Eulophidae), while that of Pediobius saulius, another eulophid, indicated an increase of parasitism rates by behavioral, phenological or biological adjustments. Compared to fully integrated host-parasitoid associations, however, parasitism rates of C. ohridella are still very low. In addition, the parasitoid complex lacks specialists, provided that the species determined are valid and not complexes of cryptic (and presumably more specialized) species. Probably, the adjustment of specialist parasitoids requires more than a few decades, particularly to invaders which establish in ecological niches free of native hosts, thus eliminating any possibility of recruitment of pre-adapted parasitoids.

Keywords

Parasitoid recruitmentAdaptationHost residence timeEulophidaeGracillariidae

Supplementary material

10530_2009_9685_MOESM1_ESM.xls (46 kb)
Supplementary material 1 (XLS 45 kb)

Copyright information

© Springer Science+Business Media B.V. 2010