It is photograph of a mottled black and white Catocala-like caterpillar with numerous white setae, posted to Instagram and Twitter. It was taken in 2014, and collected in Belem by Fernando Carvalho-Filho. The larva pupated and emerged, and it was a white witch moth. Dave Wagner, who should know as well as anyone, confirms that the morphology is consistent with Thysania.
0 Comments
Article from France24: https://www.france24.com/en/20191226-in-an-african-forest-the-enduring-mystery-of-a-giant-butterflywww.france24.com/en/20191226-in-an-african-forest-the-enduring-mystery-of-a-giant-butterfly
The article concerns a swallotail, Papilio antimachus, "the largest butterfly to appear by day on the African continent, virtually unrecorded in scientific annals." So, like white witch, we have an iconic "biggest" insect, about which we know little, including the caterpillar stage. A recent expedition of 20 people hunted for the immature stages in tCentral African Republic, exploring the entirety of a canopy liana species, the presumed host plant. No luck. It would certainly be interesting to put 20 people onto the white witch question, in the environs of one of the geographic hotspots we know of for this species. I've deleted the page on this site offering a reward for eggs or larvae of white witch. The original idea was good: if we can create excitement and incentive to rear immatures from captured females, that would be a huge step towards unraveling the basic biology. However the reward idea is inconsistent with ethics and regulations in the current era. So if the occasion arises, we would be happy to help anyone negotiate the regulatory constraints on a cas-by-case basis.
Thanks to Costa Rican correspondents for raising this issue. I exchanged some information with @gernotkunz after his recent post of a white witch observation on iNaturalist. He in turn added a white witch post to
@Renata posted a white witch observation to iNaturalist (the 152nd) for a moth in Manaus, on Dec 5, 2019. She notes that this is the second she has seen this year (uncommon luck). The first observation was from four months earlier, Aug 4. This suggests two possibilities. 1) white witches emerge as a synchronized brood before August, and individuals of that brood live as long as 4 months, or 2) white witches emerge over a period of several months, thus are not closely synchronized with respect to local seasonal conditions.
A second point: there are 6 ww observations on iNaturalist within a few km of Manaus. Either the iNaturalist members in the area are particularly diligent, or ww's are uncommonly abundant locally. The graph here shows average monthly precipitation in Manaus, and the months in which iNat observations were made. Not obvious that there is a seasonal pattern, though the data are scant. It would be additionally helpful to estimate the ages of the moths, but the photo quality makes that difficult. Phil Torres - "tropical entomologist, TV host, conservationist, science reporter, photographer, and fan of adventure" - posted a YouTube video of a white witch he happened upon in Rio Negro, Brazil. The moth is shown in the typical vertical orientation on a tree trunk. Then it flies. Nice clip. At https://youtu.be/LOZMVRi6li8
I've corresponded with Peter Møllmann, who watches witches in Bolivia. He is one of the few that have collected eggs from a female - though unfertilized. He has also recorded the white witch in flight: LINK.
A link from the above opens Mariposas de Bolivia | Witches from Bolivia, which displays photos of the witches--species related to the white witch--by Peter, Lars Anderson, and Ole Anderson. The last couple of posts discussed the recent publication of Thysania winbrechiini, a new species split from T. agrippina by Brechlin and XXX. My initial position was skepticism--is this a careful and valid revision of the genus? My new position is outrage, based on what I have learned about "taxonomic vandalism." An excellent piece in Smithsonian* discusses the general issue of "scientists" that name scores of new species based on thin evidence, not to enhance understanding (in fact, to obfuscate it), but to fuel their egos.
In the case of the T. Winbrechiini lead author: Ronald Brechlin has named 1,420 species of Lepidoptera. This is prima facie absurd. Linneaus himself managed only 166. One writer** has referred to a special category: "Brechlin and Meister" species" There is no doubt a case for investigating the genus Thysania. It even seems likely that the species designations made in 1776 (agrippina and zenobia) and 1924 (pomponia) will change when examined with modern data and technique. Hopefully a serious and careful researcher will engage this task, and repair any taxonomic vandalism that may have been committed. -------------------------------------------------------------- * A Few Bad Scientists Are Threatening to Topple Taxonomy. https://www.smithsonianmag.com/science-nature/the-big-ugly-problem-heart-of-taxonomy-180964629 ** Brechlin and Meister Species. https://breedingbutterflies.com/brechlin-meister-species/
In the last post I reported on T. winbrechiini, a newly described species split from T. agrippina. I can't authoritatively discuss the validity of this recent nomination--I am not a taxonomist--but I can ask some questions. The strength of a claim for a new species designation should be strong. Some factors that help:
Another trickier issue: is the describer conservative in considering these factors, knowing that new designation will affect how others assess the taxon long term? Or is there a predisposition for he/she to discern new species from relatively weak evidence? The case of T. winbrechiini seems to be the latter. The primary author of the new species paper is Ronald Brechlin, a German entomologist with >200 taxonomic publications. In the year 2010 alone, he put out 33 papers, describing 51 new species and many lesser taxa. That is, Ronald Brechlin made the case for a new species once a week in that year, and in many other years. This leads me to skepticism. It is not possible to rigorously make that many IDs. Where were these many taxonomic papers published? Nearly all were contributed to Entomo-satsphingia a journal founded in 2008 by ... Ronald Brechlin (and Frank Meister). My skepticism deepens. I highly doubt that true authorities on the relevant taxa reviewed the claims made in this journal. There is one small piece of follow-up that I can do, to assess the reliability of Brechlin's report of a morphological distinction between agrippina and winbrechiini. He states that "Externally in winbrechlini we ... found both a double 3rd transveral line (from the base/body) in forewing and double 2nd line in hindwing (vs. almost single lines in agrippina). I examined photos available to me (most from iNaturalist) and mapped the occurrence of these two morphologies. Red symbols indicate records for moths with double transverse lines in the hindwing, and blue symbols show a single line. There is a pattern here - the "agrippina" type alone in the north and south, "winbrechiini" type central. However this needs more data. The overlap (also noted by Brechlin) is interesting. Final note: I collected two agrippina in Roura, French Guiana, on consecutive nights at one location. Based on the Brechlin wing pattern distinction, one of these was "agrippina," one was "winbrechiini." The Bolivian iNaturalist observer petermoellmann recently obtained a white witch and held it for oviposition. After the moth died, he dissected and recovered a clutch of eggs (pictured here, from his iNat posting. Very close (!) to the holy grail, eggs from which we might first observe the larvae. However Peter has been told, and I also have the opinion from David Wagner, that these are unlikely to have been fertilized. Nonetheless, this is a significant data point: it tells us that on this date in this place, we might expect gravid females. I do not have that information in any other case. It happens that January in La Paz, Bolivia (near the observation locale) is perhaps a month or two into the rainy season. This would roughly fit the scenario predicted by David Wagner, where the larval stage occurs during the flush of new foliage with the onset of the rainy season. Peter also recorded a video clip of the flight of a white witch, HERE.
White witches might be seen almost anywhere in the New World tropics, at any time of the year. But typical observations are one-offs. If I chose the best locality (perhaps from the map in the previous post) and went there at the optimal time, I might see one or two or zero white witches (or 40--it has happened). In fact, I have visited French Guiana--a hot spot--at the onset of the rainy season, spent 10 days lighting and baiting, and saw 2 moths. So it is frustrating to know that certain individuals, or groups, routinely collect large numbers of white witches that are then sold on Ebay. The number of moths in the market is unquantifiable, but the prices (as little as $30) suggest an abundant supply. And the photo above is interesting - a stack of at least a dozen moths. The collector is in a position to know the date and time of the collection, and the size and sex of the specimen. Even one of those variables (sex) would be enormously helpful. Problem: there is every reason for the collectors, and their brokers, to hide information that might aid their competitors. Message I have sent to an online seller:
I have geo-referenced records for 214 T. agrippina, and 179 records for the sister species T. zenobia. Most are from labels for specimens in various museums. Some from personal correspondence. And more recently I have added the dozens of sightings from Inaturalist.
I placed all of these data points onto the google map embedded below. Blue symbols are T. agrippina and black symbols are T. zenobia. You can expand the map, and click on individual datapoints to ID the collector/observer. What does the map tell us? Less than I wish it did. Certainly it puts some bounds on the range, which for agrippina extends from Uruguay to Texas. The zenobia range strays much farther north, and includes the Caribbean. As to the relative abundance of both species, the map is misleading. The many records for Costa Rica are certainly related to the intensity of scientific attention for that country. Conversely, the paucity of records for the heart of the Amazon are certainly related to the remoteness from scientists and tourists. Wing details of the specimen in last post below. I am still thinking about what we can learn from wear and tear. In a 2002 paper (https://doi.org/10.1093/beheco/13.4.456), Kemp cites numerous butterfly studies that estimated age from wing wear. Specifically:
The wing wear assessments utilized the degree of fading of darker wing regions and feathering of the wingtips, rather than the extent of lost wing area per se, and are hence more sensitive to the cumulative effects of wing scale loss due to aging. Browsing Google Scholar, I find many references to some kind of "wing score index." I would need journal access to see the method details. Or a decent collection of pinned specimens from which to experiment with quantifying scale wear. I DID try to evaluate wing wear in a series of Inaturalist photos (all Florida) of Ascalapha odorata, a close ww relative. No association between wear and date. However: most photos were insufficiently clear to score. After 3 years in the freezer, my last witch from French Guiana, 2015, is mounted. My motive: when the wings of a mounted moth have dried, a critical detail is obscured. Working with the frozen specimen, I can view the frenulum, a structure that connects hind and forewings. Male moths have a single strong bristle, females have multiple smaller bristles (info here). The closeup photo below shows the stout single bristle of a male.
For nearly all of the 200+ records I have, sex is unknown. It would be enormously helpful if observers could ascertain the sex of moths encountered. This would be easy to do: white witches are most often observed in the day time, stationary on trees. It should be simple and minimally disruptive to the moth to flip it over and examine the wings, from the ventral side. 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? |
AuthorDavid Cappaert Archives
December 2019
Categories |