A field study on
Kaltenbachiola strobi (
Winnertz) (Diptera: Cecidomyiidae), was carried out between 1987 and 1993 in the highest mountain range in the Western Carpathians
located within the Tatra National Park, in southern Poland. Rearing and analysis of 5 780 cones of
Picea abies (L.)
Karst., collected from trees growing at different altitudes, yielded 30,478 individuals of
Kaltenbachiola strobi, which infested 89.10% of the cones. In case of 29.81% of cones there were more than 20 larvae of
K. strobi per cone. It was shown that
K. strobi in the Tatra Mts. is more abundant in spruce stands of the upper mountain forest zone. Significant connections between the
time of cone infestation by
K. strobi and its parasitoids and characteristic phenophases in spruce foliage and cone development, and also the development of selected
vegetation of the forest floor at different heights above sea level were determined. It was shown that the population dynamics
of
K. strobi had tendency to alternate the increase and decrease in numbers every two years. It was also discovered that every two years
spruce cones were inhabited by the population of
K. strobi with increased percentage of individuals having prolonged diapause. In total, the parasitoids reduced the population of
K. strobi by about 16–22.63%. Parasitism of
K. strobi in the lower mountain forest zone was higher than in the upper zone.
Triplatygaster contorticornis
Ratz. (Hymenoptera: Platygasteridae),
Torymus azureus
Boheman (Hymenoptera: Torymidae) and
Tetrastichus strobilanae
Ratz. (Hymenoptera: Eulophidae) were most effiecient in reduction of the population of
K. strobi, and in the lower mountain forest zone
T. azureus was the dominant parasitoid species, while in the upper zone
T. contorticornis and
T. strobilanae. It was shown that a considerable part of the populations of
T. azureus, T. contorticornis and
T. strobilanae have their diapause prolonged and highly synchronized with the diapause of their host.
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