We investigated the distribution, sex ratio, and natural enemies and nesting competition insects of mason bees, Osmia spp. in 32 apple orchards during 2006 to 2008. The rate of bee nested was 14.0±1.7%. The rate of fauna nested were Osmia spp., 66.0%, natural enemies, 21.7% and nesting competition insects, 11.6%. We collected five species of Osmia spp. consisting of Osmia cornifrons, O. pedicornis, O. taurus, O. satoi and O. jacoti. In case of collected five Osmia spp, O. cornifrons was 69.6%, which was the dominant species and O. pedicornis was 13.0% and O. taurus was 11.2%, respectively. The collecting rate of Osmia spp. was significant difference among each year and 10 locations. The sex ratio of Osmia spp. were 1:1.9 in O. cornifrons, 1:5.1 in O. pedicornis and 1:2.2 in O. taurus. The sex ratio of O. cornifrons was significant difference among each year and 10 locations. Seven species of natural enemies that attack Osmia spp. were collected in apple orchard. Trogoderma and Chaetodactylus showed the highest rates with 48% and 38% among 7 natural enemies. Also, we collected nine species of nesting competition insects. Anterhynchium flavomaginatum showed the highest rates with 38.6% among 9 nesting competition insects.

Bumblebee, Bombus terrestris is widely used to pollinate various crops, especially tomato, in greenhouses. Mason bee, Osmia cornifrons, which is using as apple pollinator. Here we investigated characteristics on pollinating activity of B. terrestris and O. conifrons at different weather conditions in apple orchard. The foraging activity of O. conifrons was more sensitive than that of B. terrestris at weather conditions including temperature, illumination intensity and wind velocity. The pollinating activity of O. conifrons was very low than that of B. terrestris at a low temperature, cloudy, rainy and windy weather. Therefore, Our results indicated that B. terrestris was suitable for apple pollinator than O. conifrons, especially in low temperature and bad weather.

Bumblebee, Bombus terrestris is widely used to pollinate various crops, especially tomato, in greenhouses. Mason bee, Osmia cornifrons, which is using as apple pollinator. Here we investigated characteristics on pollinating activity of B. terrestris and O. conifrons at different weather conditions in apple orchard. The foraging activity of O. conifrons was more sensitive than that of B. terrestris at weather conditions including temperature, illumination intensity and wind velocity. The pollinating activity of O. conifrons was very low than that of B. terrestris at a low temperature, cloudy, rainy and windy weather. Therefore, Our results indicated that B. terrestris was suitable for apple pollinator than O. conifrons, especially in low temperature and bad weather.

Currently, flies are used to pollinate Welsh onion for seed production. However, the use of flies for pollination has caused problems in Welsh onion seed production due to sanitation issues, smell, and the difficulty of feeding the flies. Therefore, we investigated the effects of pollination with bumblebees (Bombus terrestris), flies (e.g., houseflies, flesh flies, blue bottle flies), mason bees (Osmia cornifrons), honeybees (Apis mellifera) and blowflies (Lucilia illustris) in a small net screen house (2.2m×1.7m×2.5m) for onion seed production. Although the number of flies was about three times than that of other insect pollinators, fies and bumblebees showed equivalent pollination ratios, but the remaining three insect species showed lower values. For the percentage of seed set per umbel, the number of seeds per flower and umbel, bumblebees and flies showed similar results. These results showed that pollination by bumblebees can be used as an alternative approach in breeding Welsh onion. An analysis of the most appropriate colony of bumblebees for use as pollinators for breeding Welsh onion in a small net screen house showed that colony of fifty to eighty bees was the most efficient level. The visiting time on the flower and spending time from a flower to another flower of B. terrestris worker on small net screen house was 2.2 seconds and 1.8 seconds, respectively.

The Samia cynthia ricini (Lepidoptera: Saturniidae) is a commercial silk-producing insect belonging to an insect family Saturniidae in Bombycoidea. The species that has presumably been originated in India, is distributed in India, China, and Japan. Unlikely domestic silkworm the prime host plant for the species is a castor-oil plant (Ricinus communis in Euphorbiaceae). Recently, the eri-silkworm also is reared in Korea and is expected to be utilized for a diverse purpose. In this report, we present the complete mitochondrial genome of the species with the emphasis of a few major characteristics. The 15,384-bp long S. cynthia ricini (Lepidoptera: Saturniidae) mitochondrial genome was amplified into three long overlapping fragments (from COI ~ ND4, ND5 ~ lrRNA, and lrRNA ~ COI) and subsequent several short fragments using the long fragments as temperate. The primers for both long and short fragments were designed solely for lepidopteran genomes, without any species-specific primers. As a usual the genome is composed of 37 genes: 13 protein-coding genes (PCGs), two rRNA genes, and 22 tRNA genes, and one large non-coding region termed the A+T-rich region. Arrangement of the genome is identical to those of other lepidopteran mitochondrial genome, but this differs from the common arrangement found in a diverse insect order, by the movement of tRNAMet to a position 5’- up stream of tRNAIle. Unlikely previous report on the start codon for COI gene in Lepidoptera S. cynthia ricini COI gene starts with typical ATT codon located between tRNATyr and the beginning region of COI gene. The 22 tRNAs that are interspersed throughout the mitogenome ranged in length from 62 to 71 bp. All tRNAs but tRNASer(AGN) were shown to be folded into the expected cloverleaf secondary structures. More detailed structural and phylogenetic analyses among Bombycidae and Saturniidae in connection with other families in the Bombycoidea will be performed soon

The silkworm (Bombyx mori), as an industrial insect, possesses a high economic value. Casual discrimination and accumulated genetic information of silkworm varieties are essential ground for the practical utilization and long-term conservation. In this study, nine available microsatellite loci were successfully genotyped from ~50 silkworm strains preserved in Korea. According to genotyping analysis, we obtained 3 ~ 16 alleles per locus, with an average of 7.4, the observed heterozygosity ranging from 0.04 to 0.98, and the polymorphic information content (PIC) ranging from 0.06 to 0.88, revealing that some loci are highly variable. Among 54 strains 13 strains were casually identified by the presence of 17 strain-specific apomorphic alleles. Furthermore, 30 among remaining strains contained strain-specific allele combinations that are also apomorphic to each strain, allowing us to discriminate each of these from other strains by genotyping of multiple loci. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular marker for the discrimination of the silkworm strains that are preserved as hundreds in Korea, as more loci are genotyped.

Background: Proteolytic enzymes are involved in insect molting and metamorphosis and play a vital role in the programmed cell death of obsolete organs. Here we show the expression profile of cathepsin B in the fat body of the silkworm Bombyx mori during development. We also compared the expression profile of B. mori cathepsins B (BmCatB) and D (BmCatD) in the fat body during the larval-pupal transformation of B. mori in the BmCatB or BmCatD RNA interference (RNAi) process. Results: BmCatB is ecdysone-induced and expressed in the fat body of B. mori during the molting, and the larval-pupal and pupal-adult transformations, and its expression leads to programmed cell death. In particular, BmCatB is highly expressed in the fat body of B. mori during the larval-pupal transformation and BmCatB RNAi treatment resulted in the arrest of the larval-pupal transformation. RNAi-treated BmCatB knock-down sustained the expression of BmCatD during the larval-pupal transformation. On the other hand, BmCatD RNAi up-regulated the expression of BmCatB in the fat body of final instar larvae. Conclusion: Based on these results, we conclude that BmCatB is involved in the programmed cell death of the fat body during B. mori metamorphosis and that BmCatB and BmCatD contribute collaboratively to B. mori metamorphosis

Metamorphosis is a development process involving the programmed cell death of obsolete larval organs. Aspartic proteinase cathepsin D (BmCatD) is involved in the silkworm Bombyx mori metamorphosis. Here we show a novel functional role of cysteine proteinase cathepsin B during B. mori metamorphosis. The B. mori cathepsin B (BmCatB) was expressed in the fat body, epidermis, ovary, testis, and hemocyte of the larval and pupal stages. The BmCatB was ecdysoneinduced, expressed in the fat body of the molting, the final larval instar and pupal stages, and its expression led to programmed cell death. RNA interference (RNAi)-mediated BmCatB knock-down inhibited the programmed cell death of larval and pupal fat body, resulting in the arrest of larval-pupal transformation. BmCatB RNAi is up-regulated the expression of BmCatD. Based on these results we concluded that BmCatB is critically involved in the histolysis of the larval and pupal fat body, indicating that BmCatB and BmCatD are mutally regulated during silkworm metamorphosis.

The 15,338-bp long complete mitochondrial genome (mitogenome) of the Japanese oak silkmoth, Antheraeayamamai (Lepidoptera: Saturniidae) was determined. This genome has a gene arrangement identical to those of all other sequenced lepidopteran insects, but differs from the most common type, as the result of the movement of tRNAMet to a position 5’-upstream of tRNAIle. No typical start codon of the A. yamamai COI gene is available. Instead, a tetranucleotide, TTAG, which is found at the beginning context of all sequenced lepidopteran insects was tentatively designated as the start codon for A. yamamai COI gene. Three of the 13 protein-coding genes (PCGs) harbor the incomplete termination codon, T or TA. All tRNAs formed stable stem-and-loop structures, with the exception of tRNASer(AGN), the DHU arm of which formed a simple loop as has been observed in many other metazoan mt tRNASer(AGN). The 334-bp long A+T-rich region is noteworthy in that it harbors tRNA-likestructures, as has also been seen in the A+T-rich regions of other insect mitogenomes. Phylogenetic analyses of the available species of Bombycoidea, Pyraloidea, and Tortricidea bolstered the current morphology-based hypothesis that Bombycoidea and Pyraloidea are monophyletic (Obtectomera). As has been previously suggested, Bombycidae (Bombyxmori and B.mandarina) and Saturniidae (A.yamamai and Caligula boisduvalii) formed a reciprocal monophyletic group.