Science Behind the Photo #21

 

Andrew Purcell

Increasing average global temperatures are allowing alien species from Mediterranean climates to invade into more northerly areas. This is a major problem in the large alpine forest areas of central Europe. A prime example of such an invasive species is the pine processionary moth (Thaumetopoea pityocampa). This moth species, originally from the Mediterranean is now a major defoliating pest of pine stands in Europe. Species of the Pinus, Cedrus and occasionally the Larix genera are attacked. Battisti et al. report a huge shift in the moths’ range following the record hot summer of 2003:

“In the last three decades, warmer winters have led to a gradual but substantial expansion of its range both latitudinally and altitudinally. In the summer of 2003, T. pityocampa underwent an extraordinary expansion to high elevation pine stands in the Italian Alps; its altitudinal range limit increased by one third of the total altitudinal expansion over the previous three decades.”

T. pityocampa larvae cause severe defoliation of Pine and Cedar stands resulting in tree growth reductions and timber losses; their hair which is irritating can cause dermatitis on contact. Consequently, it is important for local environmental protection agencies to control the spread of this moth’s range. Traditionally, this has meant burning the moths’ nests, but there is also the potential for using biological controls. The use of Bacillus thuringiensis kurstaki (Btk) preparations is successful and aerial sprays of Diflubenzuron and Btk are carried out over large areas.

 

Referecnes: BATTISTI, A., STASTNY, M., BUFFO, E. and LARSSON, S. (2006), A rapid altitudinal range expansion in the pine processionary moth produced by the 2003 climatic anomaly. Global Change Biology, 12: 662–671. doi: 10.1111/j.1365-2486.2006.01124.x

 

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