Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 28, 2006
Publication Date: December 1, 2007
Citation: Leopold, R.A. 2007. Colony maintenance and mass-rearing: using cold storage technology for extending the shelf-life of insects. Book Chapter. In: Vreysen, M.J.B., Robinson, A.S., Hendrichs, J., Editors. Area-Wide Control of Insects: From Research to Field Implementation. The Netherlands: Springer, Dordrecht. p. 149-162. Interpretive Summary: This article describes two strategies for increasing the utility of insects as models for research and as agents to be used in pest control programs. Both strategies involve the use of cold temperature to store insects. Using cryogenic technology to lengthen the life of an insect involves a chemical and physical manipulation of the insects to enable them to be stored in liquid nitrogen at a temperature of -196 centigrade. Two related cryogenic procedures, conventional cryopreservation and vitrification, are described and the research on the cryopreservation of 5 different forms of insect germplasm is discussed. Storage in liquid nitrogen is long-term and protocols for this process exist for just 10 species of mainly dipteran insects (flies). The other strategy for lengthening the period time that insects can be utilized is the application of an insect's innate ability to deal with harsh environmental hazards such as cold temperature. Insects often respond to harsh conditions by becoming dormant. Two dormancy mechanisms that many insects possess are diapause and hibernal quiescence. Placing insects into a dormant state involves a manipulation of the insect's external environment such as slowly lowering the temperature or shortening the day length. The technical aspects of cryopreservation and dormancy are compared along with the advantages of using either of these two approaches for extending insect shelf-life. Both approaches have specific requirements for employment and both yield situational benefits relating to short- or long-term insect storage needs.
Technical Abstract: Implementation of area-wide pest control programmes using the Sterile Insect Technique (SIT) is fundamentally dependant on the ability to rear large numbers of insects and to precisely release them oftentimes at some distance from the production site. This process of producing purely biological agents for pest control frequently demands that periods of low temperature be utilized to store, stockpile or immobilize the insects to maintain quality and gain economy and effectiveness. Likewise, rearing and maintenance of often numerous laboratory colonies for the purpose conducting research to develop and improve SIT programs can also benefit from the use of this technology. Two approaches that can be used to maintain quality and to extend the utility of insects are cryopreservation and dormancy. Using either of these methods to extend the shelf-life of mass-reared or laboratory-colonized insects requires that they be closely aligned with the physiological and developmental capabilities and characteristics of a particular species. The technical aspects of this alignment are discussed, along with the advantages of using these two approaches for extending insect shelf-life. Both approaches have specific requirements for employment and both yield situational benefits relating to short- or long-term storage needs.