I have recently contemplated how a given observation might tell us more than just time and place. If we look really closely - here 1:1 macro - we might be able to say something about the age of a moth, and perhaps its sex. The moth here was collected Feb 13, 2015 in Roura, French Guiana. It exhibits more damage than most specimens I've observed. The last image below is an example of a moth that has to be much younger, from Yale's collection. I notice in particular the spray of hairs at the wing bases - these are nearly absent from the French Guiana specimen.
Because Inaturalist records have associated photos, I sampled some of these with two ideas in mind.
1) Photos sometimes exhibit damage (e.g., evident bat/bird attack) or wear. This will be more prevalent as the moths age. So, if you examined a set of images from one area, recorded in different seasons (same seasonality), and found the most perfect moths in May-June, and beat-up moths in Aug-Sep, you could infer something about the life cycle. I looked at 17 photo records from one region--Costa Rica. No pattern. Of course the sample size is tiny, and there are confounding variables. 2) Photos could be examined for small morphological variations, to see if there is a clinal change - e.g., a gradual change in some feature on a north-south gradient. I looked a set of 18 images, half from the northern extent of ww range, half from the most southerly extent. No pattern. But, 1) the sample size is small; 2) the photos are of varying quality and difficult to compare; 3) I have little idea about how to evaluate pertinent features. A much better study could be done with museum specimens, or high quality images of them. If only the British Museum were convenient ... I haven't quantified this, but my sense is that the vast majority of ww observations are of stationary moths on tree trunks. And several anecdotes suggest that a given moth will be on the same tree on successive days. Chances are, this is because the moths are nocturnal, and spend their days trying to look lichens on bark. What if an observer watched that stationary moth until after dark? It would probably be impossible to track. But what if the resting place was close to oviposition sites? Or the location of mating?
Within 24 hours I have 10 responses from the 60 Inaturalist observers of white witch. Every accompanying anecdote is helpful. Further, I am hoping that we have raised the profile of ww - more people looking a little more closely.
One intriguing item: Sandra Lambert has observed WW near Rio de Janeiro. She also posted an image (here) of a caterpillar, a good fit for T. zenobia (Janzen images here). But there are no other T. zenobia observations on Inat south of Costa Rica. I DO have museum records for T. zenobia near Rio, but these date to 1933. Could Sandra's caterpillar be white witch? The last blog post here was in Nov 2015, which was just before my trip to French Guiana to look for the white witch. Truth is, that trip was an excuse to capture the attention of my students, who followed my investigation from our school in Hartford CT (blog here). I collected 2 white witch specimens after 10 nights of light sheets and bait trapping, and learned nothing new about white witch. It had been a long shot: previous trips by others had encountered dozens of moths, which would have been a data bonanza.
I'm ready to re-engage. I've documented here the effort to accumulate records from museum collections. It is a lot of work to find <200 data points from a dozen collections. Only a few of these have associated photos. Many are incomplete, without accurate localities or collector identification. And follow-up is problematic, as most records are decades old. Recently I have become a huge fan of Inaturalist, a citizen science project that shares user observations of organisms. It is a deep dataset (<10,000,000 records). This includes some 70 observations of white witch, all of which include photos, precise locality and date info, and a user that I can email. So my next effort will be to add these to my white witch spreadsheet, and to contact contributors for more detail. |
AuthorDavid Cappaert Archives
December 2019
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