Lower organisms often provide less complex model experimental systems. Moreover, an evolutionary perspective by providing an understanding of how a more complex system emerged step by step can yield unique insights into the function of such complexity. The study of invertebrate host defense systems can also be expected to lead directly to useful applications, such as the discovery of unique molecules of pharmacological importance and the development of strategies for control of harmful insects and parasites. In addition, increasing public awareness is focused on the use of mammals for routine investigations. The high price of feeding and housing vertebrates renders the use of invertebrate model systems an attractive, and perhaps necessary, alternative.
Invertebrates are noncontroversial, inexpensive and economical to maintain as experimental animals.
Invertebrate cell culture systems are as easily maintained and are as practical as vertebrate systems.