Effects of host density and refuge on the sex ratio of progeny of hymenopterous parasitoids was tested with Bracon hebetor Say parasitizing Plodia interpunctella (Hübner). The overall sex ratio (male/total) of progeny produced per female with and without refuge was estimated to be 0.49 and 0.41, respectively. Regardless of refuge, the sex ratio decreased as host density increased. But, at host density of 128 with refuge the sex ratio was significantly lower than that without regfuge (t=-2.17, df=24; P=0.040). The number of pupae per host larva with refuge was similar to that without refuge at the host densities tested (t=-0.10, df=53.4; P=0.921). The number of attacked host larvae showed significantly different at all host densities with and without refuge (t=-3.33, df=209; P=0.001).

The effects of the genetically modified virus-resistant pepper (line: 15, 20) and the non-GM pepper (line: 2377, 915) on the insect community in the pepper cultivation area were evaluated. Sampling was conducted using yellow sticky traps and pheromone funnel traps in Anseong and Deokso fields. Total number of insects caught on sticky trap were 3273 individuals at GM pepper and 2949 individuals at non-GM pepper in Anseong and 4357 individuals at GM and 3712 individuals at non-GM in Deokso. Total number of aphids collected on leaves were 451 and 330 individuals at GM and non-GM pepper in Anseong, respectively and 79 individuals at GM and 41 individuals at non-GM pepper in Deokso. The total number of the insect individuals caught on sticky trap was not shown significant differences between GM and non-GM pepper at Anseong and Deokso fields, respectively. Also, there were no significant differences in seasonal occurrences of aphids caught on sticky traps in GM and non-GM pepper at both fields. This work was supported financially by Biogreen21 project of Rural Development Administration (No. 20070301-034-010).

The effects of the transgenic Chinese cabbage (SKCP19 line) with myrosinase gene and Chinese cabbage (SC19 line) without gene introduction on the insect community were evaluated. Sampling was conducted using yellow sticky traps and wing pheromone traps in Anseong and Deokso fields, respectively. The total number of individuals caught by sticky trap was not shown significant differences between transgenic Chinese cabbage and non transgenic Chinese cabbage at Anseong and Deokso fields, respectively (t=0.72; df=46; P>0.05, t=0.38; df=38; P>0.05). Also, There were no significant differences in density of Plutella xylostella population caught by pheromone traps on transgenic and non transgenic cabbage at both fields (t=0.59; df=22; P>0.05, t=0.52; df=18; P>0.05). This study was funded by BioGreen21 project of Rural Department Administration (No. 20080401-034-039).

In many host-parasite interactions, intraspecific competition among host could have a significant role to the host-parasite population dynamics, yet so far a few studies has been reported theoretically and experimentally(ex. Umbanhowar and Hastings, 2002). We examined the effect of larval competition using a stage-structured matrix model with parameters estimated from the Plodia interpunctella-Bracon hebetor and Sitophilus zeamais-Aniopteromalus calandrae experimental system. The maize weevil population showed a typical growth pattern of populations with contest type competition. After introduction of A. calandrae to the system, maize weevil population was dramatically decreased to be extinct. In contrast, the Indian meal moth population showed a typical pattern of scramble type competition. Introduction of B. hebetor to the system induced higher moth density and longer persistence of the Indian meal moth population than that in the maize weevil system. These results seem to be caused by differences in intraspecific competition between Indian meal moth and maize weevil. The applications of these results should be considered in biological control of Indian meal moth.