A Brief History of Texas Lepidoptera Observations on iNaturalist

As part of a research project on the distibutional biases of citizen science data such as iNaturalist, I have been examining the uploads of Lepidoptera observations (butterflies and moths) in my home state of Texas. I chose Lepidoptera because of my own particular taxonomic interests and because it offers a finite set of data to analyze. Here I present some details of the history of iNat uploads as background. All the data recited below are complete as of December 31, 2020, with most of the statistics accessed through the Explore page in the first few weeks of January 2021.

Figure 1a (below) shows a heat map of all the available Lepidoptera observations in Texas at the end of 2020. This can be compared to the distribution of all forms of life as shown in Figure 1b. These are intriguing maps but I'll reserve more discussion of them until I complete my research project. As of 31 December 2020, a total of 541,588 observations of Lepidoptera in Texas had been uploaded to iNaturalist by 26,022 observers (Fig. 1a). By iNaturalist's calculation, these document a total of 3,429 species or about 62% of the total Texas Lep fauna, which stands at about 5,502 species (Knudson & Bordelon 2018, fide @krancmm).

Fig 1a-b

History of uploads, observations, and observer base. iNaturalist was established with the first uploads by the U.C. Berkeley-based developers of the platform in March 2008 (@kueda et al.). The first Texas observation on the platform was, appropriately, an image of Texas Bluebonnets uploaded on 25 March 2008 by @lisa_and_robb:
The next three years saw only limited and apparently experimental uploads of a few Texas observations. The first Texas Lepidoptera upload of a recent living example was a Gulf Fritillary larva observed 23 August 2011 and uploaded 31 August 2011 by Kari Gaukler (@atxnaturalist):
In that first year of uploads (2011), just three observers uploaded a total of five observations documenting four species. Since those early uploads, several hundred observers have uploaded thousands of historical observations which predate the rollout of iNaturalist; the earliest "observations" of Lepidoptera in Texas now available on iNaturalist are actually digital images of museum specimens collected as far back as 1938:
Because of such uploads of historical records, a compilation of Texas Lepidoptera observations on the platform now shows some 7,587 observations through calendar year 2011. More widespread use of the platform started in 2012. Over the next five year period (2012-16), 2,664 contributors uploaded over 49,000 additional observations. The next watershed moment in the use of the platform came in 2017 when Texans began participating in the City Nature Challenge (organized by California Academy of Science and the Natural History Museum of LA County). From 2017 through 2020, 24,422 contributors uploaded nearly a half million additional observations. Table 1 (below) charts the growth of Lepidoptera uploads for the ten year time frame from the first uploads through 2020.

Growth of TX Lep Uploads

The set of figures below present heat maps of Texas Lepidoptera observations (including "historic" observations uploaded more recently) for periods representing (a) the entire 20th Century, (b) 2000 through 2009, (c) 2010 through 2019, and (d) just the observations for calendar year 2020. Available "historic" observations (i.e. through 2007) are still modest in number, particularly for the period of the 20th Century (Fig. 2a, b), predating the era of widespread digital photography. Numbers of available observations vastly increased after 2010 (Fig. 2c), mostly representing uploads of contemporary observations. For a variety of socioeconomic reasons in 2020, not the least of which was the Covid-19 pandemic, an increase of 44.5% in the total number of observers lead to a 50.6% increase in the total number of observations compared to the total number through the end of 2019 (Fig. 2d).

Fig 2a-d

My ongoing research will examine the geographic aspects of such data including comparisons to the distribution of the Texas population (an obvious comparison) and the distribution and efforts of iNaturalists who have contributed the observations.

I'm grateful to @sambiology, @mako252, @krancmm, @tiwane, and @loarie for help with some of this data and their early input on the direction of this project.

Posted by gcwarbler gcwarbler, January 22, 2021 16:59



Interesting research, Chuck. Thanks for sharing! I look forward to future posts.

Posted by tadamcochran 3 months ago (Flag)

Cool stuff! An explosion of use and interest, huh? Looking forward to the next post...

Coincidentally, I just saw two Juniper Hairstreaks today at Cedar Hollow - Lake Georgetown. I believe those are my earliest ever for Williamson County.

Posted by jcochran706 3 months ago (Flag)

Great work, Chuck!

Posted by tiwane 3 months ago (Flag)

"distributional biases of citizen science data" sounds really intriguing! I've heard it said about eBird data that you can learn as much about humans as you can about birds from it. I'm sure the same is true for iNaturalist data.

Posted by mikaelb 3 months ago (Flag)

very cool chuck!

Posted by loarie 3 months ago (Flag)

I adore this. Chuck got me started into moths (among many other things!). Really cool stuff.

Posted by sambiology 3 months ago (Flag)

This is great stuff. Hopefully it will add interest so that folks can get their 2020 Summary reports to me as the new Texas coordinator for Moths for LepSoc. Thanks for doing this Chuck and thanks again for your 2020 records of new species you have documented.

Posted by stuartmarcus 3 months ago (Flag)

Thanks Chuck. This is interesting and important. iNat is a truly amazing project.

Posted by ptexis 3 months ago (Flag)

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