Possible methods to differentiate Asian form of Lymantria dispar from the European form
The Asian form of Lymantria dispar (of which the females fly more freely that in the European form and have different host plant preferences) has been introduced into North America by trans-Pacific trade (RS 94/136). Research is being carried out in United States and Canada to differentiate these two forms. By comparing mitochondrial DNA restriction fragment length polymorphisms and sequences, it has been possible to reveal differences between Asian (from China, Japan and Russia) and North American populations. In a survey carried out in the Pacific Northwest in 1990 and 1991, the presence of the Asian form was detected in Vancouver (British Columbia), Washington and Oregon. The authors (Bogdanowicz et al., 1993) concluded that mtDNA was a useful genetic marker which provided a basis for undertaking efforts in 1992 to eradicate Asian Gypsy moth. (Note that in 1992, it was then reported that Asian Gypsy moth was successfully eradicated from British Columbia, CA).
However, as DNA analysis is a time-consuming and expensive method some work is being done on other possible detection methods. Wallner et al. (1994) have shown that it was possible to discriminate between Gypsy moth populations from the former Soviet Union, northeastern United States and from the laboratory (known lineage) by analyzing the colour spectrum of head capsules. This method was then tested on populations from Japan, China, Yugoslavia and Maryland (US) and provided separation as well as a high level of correct classification. The authors concluded that this method is a reliable tool for identifying progeny from geographic regions and perhaps families from that region, and could be used to try to discriminate between Asian and European races and also other insects.
Bogdanowicz, S.M.; Wallner, W.E.; Bell, J.; Odell, T.M.; Harrison, R.G. (1993) Asian gypsy moth (Lepidoptera: Lymantriidae) in North America: evidence from molecular data.
Annals of the Entomological Society of America, 86 (6), 710-715.
Walner, W.E.; Grinberg, P.S.; Walton, G.S. (1994) Differentiation between gypsy moth (Lepidoptera: Lymantriidae) populations by spectral colour discrimination of head capsules.
Environmental Entomology, 23 (3), 659-664.