• Korean journal of applied entomology
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• v.40 no.4
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• pp.301-307
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• 2001

The pine needle gall midge (PNGM), Thecodiplosis japonensis Uchida et Inouye, is a serious pest in pine forests in Korea. Since the first report of PNGM infestation in Korea in 1929, the infestation area has been expanded gradually. In 1975 the distribution of PNGM and its parasitoids were surveyed throughout several infested areas in Korea. Annual survey has been made for the rates of gall formation by PNGM and parasitism by its parasitoids at the monitoring sites including newly infested area in 1975 since 1980. These data were used to examine the relationship between PNGM and its parasitoids for newly invaded areas. The gall forming rate of PNGM and the parasitism by the parasitoid were 34.8 and 1.9% in 1975, respectively, while the gall forming rate and the parasitism were 20.7 and 8.9% in 1985, respectively. The relationships of densities between PNGM and its parsitoid were weak in the early stage of dispersion, but the density of parasitoid was with an asymptotic increase along with PNGMs density increase during the observation period for 10 years.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.278-286
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• 1995

Adaptation of Anisopteromalus calandrae maintained on rice weevil (Sitophilus oryzae) to an alternative host, adzuki bean weevil (Callosobruchus chinensis) was studied. A. calandrae required two generations to adapt to the adzuki been weevil. Through the adaptation, the mean($\pm$SEM) life span of th females became shorter $8.7\pm$1.3 days at the first generation to $6.9\pm$0.6 days at the second generation. Number of eggs laid per female increased from 29.3$\pm$7.7 to $68.2\pm$6.5. Consequently intrinsic rate of natural increase and net reproductive rate were increased. The generation time and population doubling time were decreased. The searching efficiency based on functional and numerical response of A. calandrae to the adzuki bean weevil were similar to each other, but the coefficient of variation decreased with the generation, suggesting that searching efficiency became stable when the parasitoid adapted to adzuki bean weevil. No time lag was required for A. calandrae adapted to the adzuki bean weevil to adapt again to th rice weevil and the searching efficiency of the parasitoid remained on a similar level for the first generation on.