A Couple of Tricks for Moth Identification Using MPG

I spend a lot of time trying to identify moths—my own images and moth observations from other iNatters. Aside from the mass of observations already identified on iNaturalist, the most prominent online resource in my arsenal is Moth Photographers Group, maintained by the Mississippi Entomological Museum of Mississippi State University,
There are lots of resources to help with identifications on MPG, including the very useful “Try Walking Through The Moth Families”,
Walk Through Moth Families
I highly recommend that page as a starting point if you are not familiar with moth families, especially the micromoths. I come back to that index time and time again, even though I’ve been studying these darned things for over two decades.

But undoubtedly the majority of my time on MPG is spent combing through the main plates of moth images to try and find a match to the moth of interest. You’ll find two slightly different sets of these plates, both with the same large set of images. The traditional one uses the “Hodges Check List” numbering sequence:
MPG Plate Index

MPG has also arranged the thumbnail plates under the newer “Phylogenetic Sequence”, which uses the “Pohl numbers” from a more recent checklist of Lepidoptera of North America.
It doesn’t really matter which index plate set you use because eventually clicking on any moth thumbnail on MPG will take you to the same species page.

Once you’ve decided which set of moth family thumbnails to look through (from either of the above lists), you have a choice of going to a set of index pages (known as “plates” in MPG terminology) showing either “Collection Specimens” or “Living Moth Photographs” (see the above screen capture). The Collection Specimens have square thumbnail images of the left wings of mounted museum specimens. Anything that has been photographed and uploaded to MPG will be seen on that set, and I’d guess that includes maybe 50 to 70% of the micromoth species and >95% of the macromoths of North America. You’ll see small button links to L, M, and S pages, meaning large, medium, or small size pages. Most modern internet connections and speeds handily support the large format; choosing the “L” format gives you more species on a page and thus fewer thumbnail pages to wander through. Here’s a link to a typical page of Collection Specimen thumbnails and a screen capture of an example of the first line of thumbnails you might see on a typical page of Collection Specimens:
MPG Collection Specimens - Acontiinae
Note that an MPG “plate” for a given family or subfamily will usually have two to several “pages” of images (small numbered buttons just above the family header). Don’t forget to look through all of the pages before moving on to the next (or previous) plate.

The “Living Moth Photographs” are an alternative to the Collection Specimens and it’s tempting to go right to those pages since we are normally trying to identify an image of a live critter, but keep in mind a very important caveat: IF a moth species has NOT been photographed in the field (and the image made available to MPG), it WON’T be on the Living Moth index pages. And a great many moths, especially micromoths, don’t have live photos available, so using only the Living Moth index plates can lead to overlooked possibilities. Always check a potential ID against the Collection Specimen plates to look for similar species. Also, the Living Moth index plates have two options, Slow and Fast. The Slow set displays one line of images per species and often has multiple image for a given species—very useful! Here's a link and a screen capture for a typical Slow page of living moths:
MPG Living Moths - Slow
The Fast set offers only a single image per species, which of course can’t include all the variation within a species—and a reminder, these are only for species which have been photographed alive. Here's a link and a screen capture for a typical Fast page of living moths:
MPG Living Moths - Fast
Again, modern internet and wifi download speeds are such that in most areas, the Slow index plates, with their multiple examples, are very convenient and most useful.

Another fairly recent innovation on MPG which can be useful is the “View by Region”, which allows you to subset all the possible species to view only those for which MPG records are available in a given region of North America or a given state.
MPG Viewing Regions
Links on each side of the View by Region button take you to an explanation of these viewing options and the list of available subsets. But another important caveat: When you look at only a regional subset of all images, it ONLY displays those species for which the MPG database (and map) have an explicit record in that state or region. For common species that’s not a problem, but for uncommon species or something you might be looking for at the edge of its range, MPG may not have a state or regional record for the species—even though the species is illustrated on the full set of MPG plates—and the species won’t show up in your geographical subset. ALWAYS check the full array of species for all of North America if you can’t find a species match in the geographic subset you look through.

One final trick I employ when I really settle into a detailed image search involves the window setup on my desktop computer screen. These searches can involve a lot of clicking back and forth between windows and browser tabs. So I have an advantage with a large screen on my desktop Mac which allows me to set up a search like this:
CWS Screen Arrangement copy
In the above example, you can see that I have my browser open to the MPG Collection Specimen plate, but I also have tabs available back to the original iNat observation and to MPG Living Moths, and to BugGuide as well. To minimize having to click back and forth among tabs (e.g., to iNat), I have downloaded an image from the iNaturalist observation—in this case an unidentified moth from @jcochran706—opened the downloaded image in Preview, cropped the image closely, duplicated it, and rotated the two versions to give me standard MPG angles of view. I arrange the two versions of the image side by side with my browser page so that the visual comparison with either the left-wing museum specimens or the right-facing live moths (standard for MPG) are immediately comparable to the subject iNat moth. The ease of finding a match for a given image of a moth (or any critter) has a lot to do with visual perception and our brain’s pattern recognition abilities. Anything I can do to facilitate those visual and mental processes will make moth identification that much easier.

Easy-peasy, right?!

Acknowledgements: I must always thank Founder Bob Patterson, Editor in Chief Steve Nanz (@steve_nanz), and all the staff and volunteers (such as @krancmm, @blocky, etc.) working on MPG who make this incredible resource available.

p.s. The screen captures of the MPG site above are sourced from the website itself but individual images are copyrighted by the listed photographers.

Moth Photographers Group. 2022. http://mothphotographersgroup.msstate.edu. [accessed 5 May 2022].

由使用者 gcwarbler gcwarbler2022年05月05日 21:50 所貼文


Excellent advice!! I started using MPG's plates for moth ID about a week ago, especially for micromoths. It has been really helpful for the grass veneers (Crambus) so far, but I didn't consider flipping/rotating live moth images to help keep the POV consistent with MPG's plates!

發佈由 owlbyr 約 2 年 前

YES. This is so great, Chuck -- I'm going to be linking this to a lot of folks.

發佈由 sambiology 約 2 年 前


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