An inventory of the butterflies of Plummers Island, Maryland documented 35 species. The data were collected from four sources: a transect survey (2006) (n=23 species), diurnal collecting (2005) (n=19), Malaise trap sampling (2005-2006) (n=8), and historical records (1904-1997) (n=10). Each of the four sources contributed species not recorded in the other three.

Introduction

Plummers Island, Maryland, a small part of the C&O Canal National Historical Park, has been a focal point of biological investigations for over a century (e.g. Shetler et al. 2006). The Lepidoptera have been sampled both recently and historically (e.g. Brown 2001). However, because most recent sampling was conducted using black light traps at night, a small but important diurnal component, the butterflies, was largely under-sampled. In order to remedy this shortcoming, we studied the butterflies of Plummers Island.

Materials and Methods

Transect survey (2006). A meandering transect approximately 1700 m in length was walked twice a week from 31 May to 2 August 2006. Every butterfly observed was identified and tallied.

Diurnal collecting (2005). John Brown made three trips to Plummers Island to collect butterflies in August and September 2005.

Malaise trap samples (2005-2006). Malaise traps were deployed on Plummers Island from April to September in 2005 and 2006 and samples were collected every two weeks.

Historical records (1904-1997). The butterfly collection of the National Museum of Natural History, Smithsonian Institution was reviewed for specimens.

All species documented, with the number of individuals collected from each source, were compiled into a table.

Results

Transect survey (2006)

• 23 species observed
• 66% of total species recorded
• 6 species not found in other sources

Diurnal collecting (2005)

• 19 species collected
• 54% of total species recorded
• 7 species not found in other sources

Malaise trap sampling (2005-2006)

• 8 species collected
• 23% of total species recorded
• 1 species not found in other sources

Historical records (1904-1997)

• 10 species discovered
• 29% of total species recorded
• 3 species not found in other sources

Discussion

The transect survey (2006) resulted in the highest number of species (23) and individuals (344), but was second to diurnal collecting (2005) in the number of species not found in other sources (7 vs. 6). The Malaise trap was the most ineffective method (8 species, 17 individuals), but still provided one species not found in any other source.

Acknowledgements

We thank the following people for their assistance: John Burns, Marie Metz, Robert Robbins, and Stanwyn Shetler. We express our gratitude to the NMNH Office of the Director for funding.

References

Brown, J.W. 2001. Species turnover in the leafrollers (Lepidoptera: Tortricidae) of Plummers Island, Maryland: Assessing a century of inventory data. Proceedings of the Entomological Society of Washington 103: 673-685.

Shetler, S.G., S.S. Orli, E.F. Wells, and M. Beyersdorfer. 2006. Checklist of the vascular plants of Plummers Island, Maryland. Natural history of Plummers Island, Maryland XXIX. Bulletin of the Biological Society of Washington 14: 1-58.