Comparative evaluation of Doolittle, Karl Jenter and Cupkit techniques of Apis mellifera Linnaeus queen bee rearing was done during spring (mid February- mid April 2013) breeding season. The highest acceptance of cell cups (66.00 %), queen cells raising (64.00 %), their sealing (60.67 %) and emergence of gynes (54.67 %) was recorded in Cupkit apparatus. Maximum weight of newly emerged gyne was recorded in Doolittle method in plastic cell cups (212.36 mg), while the mean weight was 184.96 mg in case of Cupkit apparatus. Overall, Cupkit proved to be the best option for queen bee rearing because of its better performance in terms of acceptance of larvae (66.00 %) and the number of successfully produced gynes i.e. 16 queens/colony/cycle of 12 days.
Whitefly (Bemisia tabaci Gennadius) is a hemipteran phyto polyphagous sucking insect pest which is an important pest of cotton that causes economic losses to the crop by reducing its yield and quality. Ecdysteroids such as 20-hydroxy ecdysone (20-E), play a significant role in larval moulting, development, and reproduction in pterygota insects. Receptor of 20-E, that is Ecdysone Receptor (BtEcR) of Bemisia tabaci has been targeted to prevent fundamental developmental processes. To identify potent inhibitors of BtEcr, 98,072 natural compounds were retrieved from ZINC database. A structure-based virtual screening of these compounds was performed for evaluating their binding affinity to BtEcR, and top two compounds (ZINC08952607 and ZINC04264850) selected based on lowest binding energy. Molecular dynamics simulation (MDS) study was performed for analyzing the dynamics and stability of BtEcR and top-scoring ligand-BtEcR complexes at 50 ns. Besides, g_mmpbsa tool was also used to calculate and analyse the binding free energy of BtEcR-ligand complexes. Compounds ZINC08952607 and ZINC04264850 had shown a binding free energy of −170.156 kJ mol-1 and −200.349 kJ mol-1 in complex with BtEcR respectively. Thus, these compounds can be utilized as lead for the development of environmentally safe insecticides against the whitefly.
BACKGROUND: Exposure of Apis mellifera to neonicotinoid insecticides is one of the factors attributed to the recent decline in A. mellifera populations resulting in economic and ecological losses due to loss of pollination services. Honey bees can get exposed to neonicotinoids like imidacloprid directly in the field at the time of application as well as during consumption of pollen and nectar from treated plants. So, the fate of imidacloprid in commodities to which honey bees get exposed needs to be overhauled. RESULTS: Residue of imidacloprid was investigated following imidacloprid application as seed treatment (2.4 and 4.8 g a.i. kg -1 seed) at the time of sowing and as foliar spray (17.8 and 35.6 g a.i. ha -1 ) at 70 days after sowing when the crop was at full bloom stage. The imidacloprid residue was below limit of quantification (LOQ) in flowers, necatariferous tissue, pollen from seed-treated cotton plants and honey collected from hives kept in plots with seed-treated cotton plants. However, average initial imidacloprid residue (2 h after spray) was 1.84 and 1.95 mg kg −1 in flowers; 0.22 and 0.24 mg kg −1 in nectariferous tissue; 0.88 and 0.96 mg kg −1 in pollen collected from plants sprayed with imidacloprid @ 17.8 g a.i. ha −1 at locations Faridkot and Bathinda, respectively. The average initial imidacloprid residue (21 days after spray) in honey collected from hives was 0.01 mg kg −1 . CONCLUSION: The residue in different substrates sampled from seed treated cotton plants was below LOQ. However, its foliar spray at bloom time resulted in imidacloprid residue in flower, nectariferous tissue, pollen and honey sampled from hives placed in plots.
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