The spread of the invasive locust digitate leafminer Parectopa robiniella Clemens, 1863 (Lepidoptera: Gracillariidae): the Ukrainian context

The spread and mass reproduction of phytophagous pests are often associated with global warming. In addition to economic interest, these species may be of interest in terms of biological indication of changes in climatic conditions. In this context, we considered the locust digitate leafminer Parectopa robiniella Clemens, 1863 (Lepidoptera: Gracillariidae) as a model species. This new for Europe phytophage was first discovered in 1970 near Milan in Italy. Since then, it began to spread across the continent. For the first time in 2003 the presence of this pest was recorded in Ukraine. In 2020-21 we found areas of massive leaf damage of the black locust (Robinia pseudoacacia) caused by the pest on Trukhanov island in Kyiv and some places in the Kyiv adminstrative region. Using 592 georeferenced records of P. robiniella across Europe, we modeled the distribution of the species under current climate (WorldClim) by employing a Bayesian additive regression trees algorithm (BART). The result shows that in the near future the pest can spread almost over the entire of Ukraine, although the best conditions (obviously, in terms of the bioclimate) are most likely located in the west and south of the country, and in Transcarpathia. Amongst the bioclimatic factors that determine the niche of the locust digitate leafminer, the most important are temperature factors, in particular the average annual temperature. The response curve for this factor generated by the BART algorithm shows that environmental suitability for the insect increases sharply in the range from 5 to 10 ^oC.