Leafminers are larvae of certain moths, flies, beetles, and sawflies that feed between the epidermal layers of leaves. These insects are typically quite host-specific, and the form of the mine varies considerably depending on what insect produces it. As a result, it is often possible to identify the responsible insect using only the hostplant and mine characteristics, but no one has previously attempted to organize this information into a usable guide.
For nearly a decade, I have been compiling all of the published natural history information for leafminers occurring in the continental US and Canada, integrating my own observations and rearing records, as well as those from various online sources. I have traveled extensively to search for leafminers in different bioregions, and have written or coauthored 30 peer-reviewed publications documenting some of my new discoveries, including the description of 45 new species.
In June 2019, I completed the first edition of Leafminers of North America, a self-published e-book that I made available in 18 monthly installments of searchable PDFs. It is 1857 pages long (plus a 54-page table of contents, 20-page glossary, and 68-page bibliography), illustrated with thousands of color photographs. The book begins with a 30-page overview of the natural history and terminology of leafminers, followed by over 100 pages about their parasitoids and predators, and then nearly 250 pages devoted to overviews of all the different groups of leaf-mining insects, supplemented with photographs of adult and immature stages. These introductory chapters include checklists of the described species of North American leafminers: 37 sawfly species, over 200 beetles, several hundred flies, and over 1200 moths. The remainder of the book consists of photographically illustrated dichotomous keys to leaf mines organized by hostplant genus, along with species accounts detailing the larval habits, hostplant species, and geographic distribution. Literature references are provided throughout.
The entire first edition is now available for $90 (US). Anyone who has purchased it before the end of 2019 will receive a free subscription to the second edition, which I plan to complete by the end of 2020. For those who would prefer to spread out the cost, monthly, semiannual, and annual subscriptions to the first edition are still available. For those who feel moved to contribute to my research* beyond a book subscription, I will offer the same “thank you” gifts as on my Patreon page:
- $120 or more per year ($10 or more per month): a 1-year subscription plus a signed 8 x 10 print of one of my photographs (you get to choose which one; it could be one from the book, or one you’ve seen on my blog or on BugGuide).
- $240 or more ($20 or more per month): all of the above plus a 12-month leafminer-themed calendar, which will be sent out in October.
To pay by check, please email me at firstname.lastname@example.org for my mailing address.
The main reason I’ve decided not to pursue putting this book in print just yet is that I want it to be a complete guide, and after eight years I’m still finding new things to add on an almost daily basis. I will wait at least until Fall 2019 to prepare the first installment of the second edition, because:
- I want to give people using the book (including participants in my week-long course at the Eagle Hill Institute in Maine) a chance to give me feedback, including alerting me to any mines found that don’t seem to be represented in the keys, or to any additional host and distribution records.
- I have numerous manuscripts in progress that I would like to finish up, including a big one on leaf-mining beetles; others on muscoid and agromyzid flies (describing still more new species of the latter); and several involving various groups of leaf-mining moths—I have an essentially unlimited supply of new moth species to describe, but unfortunately a very limited supply of microlepidopterists with the expertise and time to help with those; nevertheless I’m optimistic that some progress will be made this year. I’m also hoping to make some headway with papers on leafminer parasitoids, but the supply of microhymenopterist time and expertise is similarly limited.
- My wife Julia and I have received three small grants to cover leafminer collecting trips in summer 2019: we will be exploring some prairies in the Midwest; visiting Black Rock Forest in New York’s Hudson Valley; and completing our ninth annual surveys for galls and leaf mines on Nantucket Island, Massachusetts.
- I’m excited to begin work on a similarly hostplant-based guide to North American sawfly larvae (both internal and external feeders).
* I am conducting this research independently, and my expenses are considerable: travel; photography equipment; collecting vials; pins, vials, and other materials for preserving insects; postage for sending specimens to specialists around the world; page charges for publishing my discoveries in scientific journals; and so on. If you are aware of a foundation that gives grants to fund projects of this sort (to unaffiliated researchers without PhDs), please let me know, and if you would like to make a donation of your own without purchasing the book, you can do so here:
If you are interested in supporting this ongoing project in non-monetary ways, there are a few other ways you can help. Working as a field botanist, I have a good grip on plant identification in New England, but I need help figuring out some of the leafminer host plants I’ve found elsewhere in the US. I have uploaded photos of these on my Flickr page here, organized by location, and I would appreciate any comments. As of February 2019 I am posting mystery plants on iNaturalist instead.
I am also interested in seeing photos of leaf mines. Feel free to submit images of unidentified mines to this page on BugGuide.net, which I check regularly. Reviewing these helps me refine the keys, and often alerts me to the existence of leaf mines that are unknown to science. Ideally, photos should show both sides of the leaf, and backlit shots can be very helpful. If you prefer iNaturalist, please add your photos to this project; there is no need to tag me.
For an introduction to the world of leafminers, see chapter 10 of my first book, or you can see all of my blog posts about leafminers here. There are also several great websites dedicated to European leafminers: