Expanding our knowledge of the aphids of the park
Expanding our knowledge of the aphids of the park
Aphids are small plant-feeding insects with complicated life cycles. Species of aphids are generally restricted to a narrow taxonomic range of hosts, and host identity is usually necessary for correctly identifying an aphid. A preliminary survey conducted in 2003 indicated that the Smoky Mountains harbor a diverse aphid fauna. This survey was general and did not target any area or host taxon in particular. In 2004, areas of the National Park that contain particular plants known to host aphids will be targeted for sampling. Some of the targeted hosts will be oaks, poplars, asters, sedges, and ferns. Furthermore, many aphids are tended by ants, and working out these aphid-ant relationships will be a secondary focus of the project.
The second of three proposed years of sampling aphids took place in the Great Smoky Mountains National Park in 2004. Aphids are small plant-sucking insects with complex life cycles, and knowledge of their host plant is often critical in being able to identify the species. Aphids excrete large amounts of honeydew which attracts attendant ants. Colin Favret and undergraduate student Joshua Duggan spent a combined total of seven weeks collecting in the park in May and June, making almost 200 collections of aphids directly off of their host plants. Host plant vouchers and attendant ants were also collected.
During the fall semester Colin and Josh mounted a series of adult aphids from each collection, making almost 500 microscope slides in the process. All the slides were databased and labeled with collection locality and host data. The specimens were identified as possiple in early 2005. In 2003 we identified 37 species of aphid. In 2004, we determined 63, 48 of which were new records.
In December, Colin and Josh attended the DLIA ATBI annual meeting in Gatlinburg where they presented their preliminary results. One interesting find is the near ubiquity of the foxglove aphid in the park. This cosmopolitan species is one of the few polyphagous aphids. In mid- to late May it was in very large numbers in the park, and we found it on a large number of hosts. In 2003, we even found it on squawroot, the first record of an aphid feeding on a parasitic plant.
