The first generation of Borearctia menetriesii offspring has now come to end of its life cycle. Out of some one hundred caterpillars, nineteen have been successfully reared. They produced ten males and nine females. Out of these eleven were reared in Siberia and eight in Finland. When we consider the fact that eighty caterpillars were reared in Finnish conditions and twenty in Siberian, we can calculate that the success rate was much higher in the native range of the species.
Fennoscandian autumn and early winter are humid, which resulted in high mortality of grown up and overwintering caterpillars. You can imagine the feelings of experienced caterpillar specialists when all the young ones of this unique species are perishing to disease... That was an important, but bitter lesson. We can now conclude that this species is very sensitive to fungal disease and will only thrive in dry, continental climate. So Russia wins 5-1, proportionally, in rearing this species. Congratulations to Russia!
In spite of these hard-earned lessons, there has been some success. In a high-tech Swedish laboratory, newly hatched individuals have been analysed for their semiochemicals. The female attraction pheromone has been identified with some confidence. So, Sweden also wins their game 1-0. Congratulations to Sweden, too!
The chemical composition of the pheromone will not be disclosed until it is certain that use of the pheromone will not harm wild populations of the species.
Preliminary field tests with the pheromone have now been carried out. These matches took place with eight lures during the summer in Amur, Ural, Finnish Karelia, Kainuu, and Härjedalen. Not a single male was observed in these tests, so B.menetriesii won this time 8-0. However, as the species has been observed on the wing only on odd-numbered years in most of its localities, anything else would have been a sensational result.
We are now starting to plan next year’s monitoring programme. Your suggestions for methods will be appreciated. The plot is intense, the game is tough, but in the end science and nature conservation will win. Stay tuned.
2012-08-30 Hannu Saarenmaa
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