Population Ecology

, Volume 48, Issue 1, pp 59–70

Climatic and intertrophic effects detected in 10-year population dynamics of biological control of the arrowhead scale by two parasitoids in southwestern Japan

Authors

    • Institute of Biological Control, Faculty of AgricultureKyushu University
  • Takashi Matsumoto
    • Graduate School of Human and Environmental StudiesKyoto University
  • Takao Itioka
    • Graduate School of Human and Environmental StudiesKyoto University
  • Norio Ishida
    • People’s Institute of Environment
  • Masaaki Takanashi
    • Department of Citrus Research, National Institute of Fruit Tree ScienceNational Agriculture and Bio-oriented Research Organization
    • Department of Integrated Research for Agriculture, National Agriculture Research Center for Tohoku RegionNational Agriculture and Bio-oriented Research Organization
  • Wataru Ashihara
    • Department of Citrus Research, National Institute of Fruit Tree ScienceNational Agriculture and Bio-oriented Research Organization
    • Department of Plant Protection, National Institute of Fruit Tree ScienceNational Agriculture and Bio-oriented Research Organization
  • Mitsuko Kohyama
    • Graduate School of Bioresource and Bioenvironmental SciencesKyushu University
  • Masami Takagi
    • Institute of Biological Control, Faculty of AgricultureKyushu University
Original Article Special feature: Global climate change and the dynamics of biological communities

DOI: 10.1007/s10144-005-0243-y

Cite this article as:
Tuda, M., Matsumoto, T., Itioka, T. et al. Popul Ecol (2006) 48: 59. doi:10.1007/s10144-005-0243-y

Abstract

Relative effects of weather and three-trophic interactions were studied for a classical biological control system consisting of the arrowhead scale Unaspis yanonensis, known formerly as a serious pest of the Satsuma mandarin orange Citrus unshiu, and its two introduced parasitoids, Coccobius fulvus and Aphytis yanonensis. Yearly population responses of the three insect species on a per-tree basis for up to 10 years at two orange groves were analyzed by general linear models, with a backward stepwise procedure, to select among abiotic (summer/winter temperature and rainfall) and biotic (densities of the three insect species and orange bearing in the previous years) independent variables. Temperature positively affected the arrowhead scale and the two parasitoids. A negative correlation of rainfall was detected for all three insect species. Mandarin fruiting showed negative delayed density dependence, thereby supporting the observed alternate bearing phenomenon in mandarins, presumably due to physiological imbalance triggered by climatic factors. The arrowhead scale was negatively correlated with fruit production in the preceding years, possibly due to reduced resistance in subsequent years of mast fruiting. We found a negative correlation of the arrowhead scale with Coccobius only in a single grove and none with Aphytis. Thus, it appears that bottom-up forces may be more important than top-down control by the parasitoids in the post-transient phase of this system.

Keywords

Time series dataEndogenous versus exogenous factorsDiaspididaeGlobal warmingSpatial heterogeneityHost-density dependence in parasitism

Copyright information

© The Society of Population Ecology and Springer-Verlag Tokyo 2005