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THE EFFECT OF THE RELEASE OF GYPSY MOTH STERILE MALES IN THE PARK OF JELSA ON THE ISLAND HVAR
Miloš Maksimović
; Institut za zaštitu bilja, Beograd
Sažetak
Three times release of irradiated males of gypsy moth in the Park of Jelsa on the Island Hvar from 1969-1971, has brought strong reduction of the population density in F₁ generation (Maksimović, M.,1971a,1972a ). The population dynamic was followed in F₂ generation too, and these data are presented now. The density of egg-masses throughout the period of 7 years (Graph 1) compared with the check population in the Park of Stari grad, has shown marked decrease after second release (1970) and much more after third release (1971) of irradiated males. In the check population the density of egg- masses was growing slow and increased continuously till 1972. In F₂ generation (1973) was achieved a small increase in the density in the Park of Jelsa. Egg-masses were also tested on the qualitative changes. When average number of eggs per egg-mass (Tab. 1) was multiplied with total number of egg-masses it was achieved strong decrease of eggs in 1971 and 1972 in Jelsa (Graph 2). This result confirmes the influence of irradiated males in 1970 and 1971. In the Park of Stari grad, the increase of egg-masses was continued as well as the total number of eggs. The productivity of females was not always a sure sign for the change of population density. Therefore it was tested also the number of hatched larvae (Graph 3). Rapid decrease of hatching in the Park of Jelsa after second release of irradiated males 1970 was continued after third release in F₁ generation. The translocation of sterility is visible in F₂ generation, but less then in F₁ generation. In the Park of Stari grad hatching was different and changeble. It resulted from unconvenient food and others ecological conditions. When the percentage of hatched larvae was multiplied with total number of eggs, it was achieved a strong decrease of the population density in the Park of Jelsa (graf.4). The density dropped under the density in the Park of Stari grad. This is the result of cummulative influence of the release of irradiated males throughout three generations. The rearing of F₂ generation on artificial dict, has confirmed the translocation of sterility.
Ključne riječi
Hrčak ID:
165201
URI
Datum izdavanja:
25.1.1975.
Posjeta: 933 *