Summarized Project Data

County List

A county list of species has been prepared in tabular format. This list is in systematic order, based on Pohl et al, 2016 “Annotated taxonomic checklist of the Lepidoptera of North America, North of Mexico”, but including more recent revisions. Several species have yet to be described and these have been given provisional positions in the list. Also included in the list are several complexes of difficult-to-identify species. The number given in the first column is the traditional number used by the Moth Photographers Group, based on the Hodges Checklist (1983), see: http://mothphotographersgroup.msstate.edu/Plates.shtml

A symbol is given for each occurrence of a species in a county, based on the most recent date seen. The legend to the symbols can be found at the top of the first page. Additional columns give the first and last year seen, the Massachusetts classification for State-listed species, a general status (mainly indicating which species are introduced) and an automated assessment of each species’ status in Massachusetts. This file will be regularly updated.

The automated status assessment includes an estimate of how well distributed each species is across the State, based on the number of regions recorded, plus an estimate for the species abundance, based on the number of 5×5 mile grid squares it was found in. These have been calibrated differently for the microlepidoptera and macrolepidoptera to account for the difference in the number of records available for these two groups. These should be used as a rough guide only, especially for the microlepidoptera. Species not found since 1950 are given ‘uncertain status’. Those species for which the existing records are doubtful are given ‘uncertain occurrence’. How to cite this document: Mass Moths Team, 2022. County Records of Massachusetts Moths. Version [date]. Downloaded from MassMoths.org [date].

Download the County List (PDF):

Past Massachusetts Moth Lists

Massachusetts was the first US State to publish a list of Lepidoptera, in 1833. This was prepared by Thaddeus William Harris for E. Hitchcock’s ‘Report on the geology, mineralogy, botany, and zoology of Massachusetts’. The list contained 430 species of Lepidoptera, of which 50 were butterflies and 380 were moths. Harris states 428 Lepidoptera in his summary list, but it seems he miscounted his own list. However, of these 380 species of moths, only 105 were named and only 93 of those are identifiable to species recognized today.

The next list was published a century later by D.W. Farquhar in 1934 as part of his Harvard Thesis covering the Lepidoptera of New England. Extracting the Massachusetts data in this list results in 1253 species. This list was prepared by going through published literature and various collections, in particular that held by the Boston Society of Natural History.

The only other list of Lepidoptera published from the State was by Kimball & Jones in 1943, but covering only the islands of Nantucket and Martha’s Vineyard. They included a more comprehensive list of microlepidoptera and were therefore able to list more species than Farquhar, despite covering a much smaller area: 1383.

Literature

• Farquhar, D.W. (1934): The Lepidoptera of New England. Thesis submitted to Harvard University. Cambridge, Mass.
• Harris, T.W. (1833): VIII. Insects. pp. 566-595, in Hitchcock, E.: Report on the geology, mineralogy, botany, and zoology of Massachusetts: made and published by order of the government of that state. Part IV. A Catalogue of Animals and Plants. Amherst [Mass.]: Press of J.S. and C. Adams, 1833.
• Kimball, C.P. & Jones, F.M. (1943) The Lepidoptera of Nantucket and Marthas Vineyard Islands, Massachusetts. The Nantucket Maria Mitchell Association.

County Coverage

The graph below plots the number of species found so far in each county. Middlesex has by far the most species, whereas Suffolk (Boston) has the least. Middlesex is the most populous county and the third largest, whereas Suffolk is the second smallest and the third most populous. Middlesex is large enough to harbor a lot of (semi-)natural areas and many naturalists to record the natural history (although one single naturalist – Tom Murray – has found the majority of the moth species). Suffolk on the other hand is very urban, with proportionately far fewer moth-friendly areas. Nevertheless, Suffolk, like all counties, still has plenty of scope to add new species. Graph from Mar 2023.

Grid Square Coverage

For mapping, locality data are allocated to grid squares. Each grid square is approximately 5 x 5 miles. There are 423 full or partial grid squares covering Massachusetts (land only) and we have moth records from 95% of these squares. However, only 4 squares have more than 1000 species and only 42 (10%) have more than 500 species. There is therefore a huge potential for finding new grid square records. The map shows the number of species recorded for each grid square (as of Jan 2022).

Recent additions to the Massachusetts List

The graph below shows how many species have been found new to Massachusetts over the last 21 years. There was a steady increase in new species with a peak of 76 species in 2016. The reason for this increase is certainly due to the increased interest in moths resulting from the new websites, especially the Moth Photographer’s Group and Bugguide, which have made identification a lot easier, especially for the smaller moths. It is certain that there are many more species to be found and 10 to 20 species per year for the next few years is realistic.

Have we lost any species in Massachusetts?

Based on the year each species was first recorded and the year when each one was last seen, we can construct the graphs below. The blue line represents the cumulative numbers of species as they were found over each 20 year period. The red line shows the cumulative number of species not seen for at least the previous 20 years. The green line is the difference between these two numbers and represents the number of species potentially still occurring in the State. The upper graph shows the numbers for all species and the lower graph shows just the numbers for macro-moths, i.e. the better studied group of moths.

The upper graph shows that 318 of all species (11%) have not been seen for more than 20 years, i.e. they were all last recorded prior to the year 2000, many long before that. Among the macros, 114 species (9%) have not been found over this time period. This ‘loss’ has been counteracted by a tremendous increase in species found over the last several years, so the net number of species is still increasing, even for the macros. Negative data is notoriously difficult to interpret and some of these species could well be refound, in the same way that new species are still being found. A few of these species, especially those taken from older literature sources, may have been wrongly identified. It must be remembered, however, that Massachusetts in the 19^th and early 20^th centuries was a very different place than today and the biomass was probably considerably higher. The proportions of the various habitats were different and there were considerably more natural areas available, with hardly any light or pesticide pollution.

The number of ‘lost’ species tends to increase from around 1940 and appears to be still increasing, but maybe at a lower rate. This could represent the effects of increased pesticide use and other pollutants during this period, but also the increase in urban development. Some species may have been pushed out of Massachusetts due to changing habitats or climate change.

These numbers may change in future as the database is developed and more historical data, especially from collections, are captured.