Plasticity in Voltinism of the Successsful European Neozoon Phyllonorycter robiniella (Lepidoptera: Gracillariidae)

摘要

In the city of Marburg, Germany the phenology of Phyllonorycter robiniella (Clemens 1859) was studied in the vegetative periods of 2002-2009. On several study sites in the city, controls and collections were conducted on the leaves of the only feeding tree Robinia pseudoacacia Linnaeus 1753 on a weekly basis. During all studied years, the leaves of R pseudoacacia were settled shortly after the completion of the flowering of the trees in June. Up to the abcisission of the leaves in autumn, several generations of the moth were completed. In 2005, three generations were completed, in 2006 three generations were completed and a forth generation was started but could not be completed due to leaf abcisission in autumn. In 2007, 2008 and 2009, four generations were completed at the identically study sites. The duration of the different generations differed. The second generation during summer is completed in a shorter period of time than the others. In general, densities are low in spring and much higher in autumn. Mortality factors during summer (parasitation), autumn (predation) and winter (abiotic factors) are assumed to be high. Therefore, the population has to start in low numbers in the following spring again. These data are discussed in view of the properties of a successful neozoa in Europe.