History, rate, and factors of invasion of lime leafminer Phyllonorycter issikii (Kumata, 1963) (Lepidoptera, Gracillariidae) in Eurasia

Abstract

The history, rates, and factors of the invasion of lime leafminer Phyllonorycter issikii Kumata, 1963 (Lepidoptera, Gracillariidae) in Eurasia are studied. In 27 years (from 1985 to 2011), the leafminer range in Europe and Western Siberia reached 4086000 km² or 60.4% of the total range of the indigenous species of the Tilia genus. It is reported that the leafminer undergoes three stages of invasion (arrival, establishment, and spread) over a period three years. The maximum invasion rates (from 80 to 85 km per year) of westward and eastward spread from the recipient range were measured. It is shown that the rate of invasion slows down on the boundary of a host-plant range. The high rate of invasion of the lime leafminer Ph. issikii is associated with the conditions as follows: a wide range of host trees, a lack of any regulation effects of the third trophic level representatives, and no direct rival of the leafminer. In addition, the high reproductive potential of the species, the pattern of its dispersal (anemochory), and the possibility to transform the ratio between the intrapopulation forms under the impact of population density can contribute to this process.