Galls and Leaf Mines of Nantucket and Tuckernuck

Report submitted in fulfillment of a 2011 Nantucket Biodiversity Initiative grant.

The galls and leaf mines produced by insect larvae (and mites, in the case of galls) are often distinctive enough to identify their makers. In fact, there are species of both gallmakers and leafminers that can only be reliably identified by the signs they leave on their host plants, in the absence of DNA analysis. Insects such as gall wasps (Cynipidae), gall midges (Cecidomyiidae), and small moths (microlepidoptera) are often underrepresented in biodiversity surveys because of their small size and the difficulty of identifying them without host material. We reviewed the species listed by Johnson (1930) and were confident we could detect many additional species in a few days of focusing on galls, leaf mines, and other invertebrate signs. We conducted surveys on Nantucket from September 7-10, 2011, and Tuckernuck on September 10. On Nantucket, we focused our searches in several 10 ha biodiversity plots established by the Nantucket Biodiversity Initiative: Squam Swamp on Sept. 7, Madequecham on Sept. 8, and Coskata on Sept. 9. We visited a few dune and grassland plots, such as Wyer’s Point, but did not find any galls or leaf mines in these habitats. For the three biodiversity plots and Tuckernuck, we recorded every species we detected, and this location information is given in the species list accompanying this report. We found a number of additional species opportunistically at other locations, indicated on the species list in the “GPS” column and shown on the accompanying map.