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Three different races of lepidopteron silk moth Bombyx mori were used in reciprocal and inter se crosses to determine heterosis effects at F(1) and recombination loss at the F(2) generation for three fitness traits (fecundity, larval duration, survival rate) and four productivity traits (larval weight, cocoon weight, shell weight, filament length). Eleven mating types were represented in the present study, including three pure breeds and a variety of F(1) and F(2) populations arising from regular and reciprocal crosses, respectively. Equations were derived to evaluate heterosis, maternal and overdominance effects for the above traits. Estimates of heterosis and overdominance effects revealed significant heterosis effects for all the traits, but overdominance was only seen for larval duration (favorable effect) and survival rate (unfavorable effect). Maternal effects were significant for the majority of the traits under study. The results revealed significant reduction for all the quantitative traits from F(1) to F(2), except for larval duration. The most obvious explanation for the reduction of fitness parameters and productive traits is the reduction in heterozygosity from F(1) to F(2) (it is expected that one half of the heterozygosity of F(1) is lost in F(2)). For larval duration this explanation seems insufficient and breakdown of epistatic gene effects (i.e. recombination loss) has been suggested.

Insecta is the biggest group of animals on earth. The insects are thought to be one of the biggest biological resources that have not been fully exploited by humans. China is one of the earliest countries to exploit insect resources in the world and has been the top producer for over one thousand years of many insect-related industrial products, such as silk, insect wax and Chinese gallnuts. The exploitation and industrialization of insect resources in China is generally classified into four different levels. The first level is the direct utilization of insect bodies and their secretions, the history of which can be traced back for thousands of years. This level includes the culture and utilization of the silkworm Bombyx mori, the Chinese honeybee Apis cerana cerana, the Chinese white-wax scale Ericerus pela, the Chinese gall aphid Schlechtendalia chinensis, and the lac insects Kerria spp. Additionally, numerous other insects are typically used for Chinese traditional medicines and food, such as Eupolyphaga sinensis, Opisthoplatia orientalis, Aspongopus chinensis, Martianus dermestoides, Polyrhachis vicina, Hepialus spp, Vespa, Hydrillodes repugnalis, and Tenebrio molitor. Pollinators (Megachile rotundata, Osmia cornifrons, O. excavata) and ornamental insects like butterflies, katydids Gampsocleis grafiosa, and fighting crickets Scapsipedes micado are also among the insects included in this level. Accordingly, a related industry is insect-breeding, including sericulture and apiculture, which lays the basis for all insect industrialization. The second level is the utilization of insects as enemies of pests and insect pathogens for biological control. The enemy insects, including the egg parasites tricogramma Trichogramma spp, the seven spotted lady beetle Coccinella septempunctata, the Chinese green lacewing Chrysopa sinica, and Anastatus sp. could be produced in large scale. The insect pathogens that have been extensively used for commercial biocontrol in China include Helicoverpa armigera Nucleopolyhedrovirus (HaSNPV), Ectropis oblique Nucleopolyhedrovirus (EcobNPV), Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV), Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), Plutella xylostella Granulosis (PxGV), Pieris rapae granulosis (PiraGV), and Bacillus thuringiensis (Bt). Related industries include the biopesticide industry and the enemy insect production industry. The third level of utilization is the extraction and synthesis of insect materials with diverse bioactivities. Some insect pheromones and hormones extracted from insect bodies or chemically synthesized have been used for insect pest control and for regulating the silkworm breeding. Toxins from honeybees and wasps have been used in medicine. Some insect materials from the larvae of honeybees, silkworms, tasar silkworms, and houseflies have been developed into health products. The fourth level is using the insects as bioreactors to produce peptides for medical and veterinary uses. Hundreds of foreign genes have been successfully expressed in the insect cells and larvae. The hGM-CSF expressed in silkworm pupae is commercially available. In this article, we review the culture and utilization of important industrial insects in China.

Sericulture has been on developing foot hills till today in Pakistan. It is for the past few years that this industry has received recognition through greater research on the nutritional aspects. Various experiments i.e., nutritional supplementation and searching alternate food plants have been on way with varying degree of success. The present approach includes the very much neglected aspect of trying mulberry varieties and working out their impact on the silkworm growth/ development and silk yield. In Pakistan three varieties of mulberry Morus alba, M. nigra and M. indica are commonly found, these were selected for the present studies and the already established mineral dose 0.2 %N +0.1%P+0.3%K+0.1%Ca+0.15%Mg+0.15%Mn was supplemented to them through dipping method. Amongst the so designed nine treatments those in which the silkworm larvae were fed on M. nigra leaves in any form /combinati-yielded best results, as the larvae in these treatments consumed more food (73.71 gm/10 larvae) and converted maximum (77.22%) of it into body matter. This improved silkworm growth, a primary parameter for increasing the over all production and resulted in better cocoon size which weighed heavier (2.43 gm/cocoon and 1.10 gm/shell) as compared to rest of the test treatments (0.67 and 0.70 gm/shell on M. alba and M. indica, respectively).