Insects are the most prosperous group of organisms on the earth. There are more than one million known species. Insects that are involved in human activities, such as useful insects and harmful pests, represent only a few of the many species of insects; most have little impact on our life.
Among the useful insects, silkworms and bees are well-known examples. Silk and honey are produced by silkworm and honeybees, respectively, and have been used by humans for a long time. Such use has been regarded as a kind of industrial applications of insects for human use.
Industrial use of insects can be divided into the following four categories: (i) utilization of individuals; (ii) utilization of their products; (iii) utilization of microorganisms related to insects; and (iv) utilization of their specific biological properties (Fig. 1).
Utilization of individuals
Well-known cases of utilization of individual insects are natural enemies and insect pollination. Natural enemies have been used since ancient times for pest management. In recent years, some companies produce large numbers of natural enemies to be sold for insect pest management. This can be referred to “natural enemy formulation”. Examples of taxa used for natural enemy formulation are spider mites and parasitoid wasps, which are mass-produced in the laboratory. In addition, by utilizing the pollen-borne behavior of insects, honey bees and bumble bees have been widely used for pollination of crops.
Utilization of their products
Since ancient times, humans have used polymeric substances produced by insects. Typical examples are silk and honey produced by silkworms and bees, respectively. Particularly, in Japan, since the opening of the country in the late 1800s, the sericulture industry had been a key factor in the economy of the country. For honeybee utilization, the recent trend is an increased demand for functional byproducts such as royal jelly and propolis in addition to honey. Also, in Southeast Asia, the production of white wax and rack, which is resin produced by scales, has been established as an industry.
Utilization of insect-related microorganisms
Parasitic insect-related microorganisms such as bacteria, viruses and fungi have been utilized as a microbial pesticide for pest control. As control agents of lepidopterous pests, Bacillus thuringiensis (Bt) has been studied since the late 1970s, and has been commercialized. Further, as a unique system using nuclear polyhedrosis virus (BmNPV), a virus pathogenic to silkworm, has been established for producing a useful substance in the silkworm and has been commercialized.
Utilization of insect-specific properties
The utilization of insect specific properties is attracting much attention in recent years as industrial applications of insect technology have expanded. It is a new field of research attempting to analyze the specific physiological properties of insects and establish a technology for helping humans by using the most advanced techniques such as molecular biology and genetic engineering. The target properties for utilization are certain insect-specific genes, metabolism, products and useful cells derived from insects.
This review provides an overview of the current state of research on utilization of insect properties as a new technology.