It is especially dangerous for those with tender feet - which means most Westerners. The main trails often used bridges to cross the many rapids occurring throughout the countryside. It turns out that Styrax serrulatus is very rare in Nepal, only occurring in the lowland sub-tropical forests. It became apparent that to find the plant would be difficult enough, but to find one with living aphids would be quite an occasion. We got lucky on the fourth day.
Further study indicates that the aphids collected are in all likelihood a new species.
This is not that surprising, since the aphids have only been well-studied in Southeast Asia, and the galls are known to occur throughout east Asia. Styrax serrulatus was subsequently analyzed for DNA sequence variation with respect to the other members of the genus that have been looked at thus far. Although the data is still preliminary, it appears that this species' closest relatives also occur in Asia and this whole group is most closely related to the two species of Styrax native to the southeastern United States, an example of intercontinental disjunction. The disjunctions in the genus are thought to have arisen through the range contraction of once widespread species beginning as early as the Tertiary period and extending to the Pleistocene. The information gathered on my trip to Nepal will help scientists to understand the composition, relationships, and biogeographic history of forests in the northern hemisphere.