Green fluorescent protein (GFP) is a protein in the jellyfish Aequorea Victoria [8] that exhibits green fluorescence when exposed to light. The protein has 238 amino acids, three of them (Numbers 65 to 67) form a structure that emits visible green fluorescent light. In the jellyfish, GFP interacts with another protein, called aequorin, which emits blue light when added with calcium. Biologists use GFP to study cells in embryos and fetuses during developmental processes.

Another closely related exotic species, the apple ermine moth (AEM) Yponomeuta malinellus (Zeller) was found in B.C., Canada, and northwestern Washington State in the early 1980's. AEM and CEM larvae and adults are essentially identical in appearance, biology, and time of occurrence. The primary difference in the two species is their development on different host plants, with AEM larvae feeding exclusively on apple foliage. The AEM has rapidly expanded it's distribution in the Pacific Northwest, and in 1995 is found in most of Washington State and northwestern Oregon in the U.S.. This dispersal, apparently through natural spread of adult AEM, has been monitored by both the Washington State (WSDA) and Oregon Departments of Agriculture (ODA). Surveys for AEM have used an AEM pheromone attractant developed in 1986 by the USDA ARS Yakima Research Lab. Defoliation of apple trees by AEM has been severe in some areas of northwestern Washington, and biological control agents from Europe and Asia have been introduced in an attempt to reduce AEM populations, damage, and pesticide usage (Unruh et al. 1993). Discovery of CEM in 1993 in B.C., Canada, prompted an initial detection survey in Washington State by WSDA that same year. However, although the pheromone attractant for CEM is known from European research, survey results were obscured by the inability to identify collected adults as either AEM or CEM. Differentiation of AEM and CEM adult moths became possible when DNA-based identification techniques were developed by researchers in 1994 (Sperling et al. 1995). The presence of CEM in Washington State was first confirmed in 1994, based on larval collections from ornamental hawthorn foliage in Bellingham, Whatcom Co.. Distribution survey and evaluation of survey methods for CEM, using genetic identification techniques, were conducted in 1995.