Arachnews: March 16, 2020
The week in arachnid art, news, events, and science.
Published in
11 min readMar 16, 2020
In this week’s edition: incredible nature photos, spider with gun, mouse vs. scorpion, #PruittData developments, the return of the horseshoe crab debate, cute new African jumping spiders, and more.
Art & Media
- Photographer Aloke Sahu found this tiny jumping spider on a tree in Cebu, the Philippines. It is in subtribe Simaethina, but beyond that its identity is a mystery. Coleopterist Ainsley Seago speculates it might be mimicking a pachyrhynchine weevil. The find has also provoked an interesting discussion on Twitter about the threat of poaching and smuggling for rare, photogenic spiders like this. [Instagram]
- Shahan Derkarbetian posted a photo of a Sitalcina harvester from southern California, which reminded Steven Wang of a similar one he’d found near Nevada’s Hoover Dam. Marshal Hedin chimed in to say it’s probably an undescribed species of Texella. [Twitter]
- This quick test, “made as a joke”, was so popular that indie dev Trixelized put it on itch.io as a pay-what-you-can download for Windows. (The source code is available on their Patreon.) [Itch.io]
Education & Outreach
- In a tense scene in Netflix’s new nature documentary series Night on Earth, a tiny grasshopper mouse battles a scorpion in the Sonoran Desert. NPR’s podcast Short Wave breaks down the fight with the California Academy of Sciences’ Lauren Esposito (repping scorpions; she’s also appeared in Arachnews for her work on face mites) and the University of Oklahoma’s Ashlee Rowe (grasshopper mice). [NPR Short Wave] [Transcript]
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By the way, if you don’t have Netflix, here’s a similar video from National Geographic.
- This great drawing from last weekend’s Staffordshire Invertebrate Science Fair shows all the different animals commonly called “daddy long legs”: cellar spiders (Pholcidae), crane flies (Tipulidae), and harvesters (order Opiliones). [Twitter]
- “Explosions, cars on fire, gun shots, homemade flamethrowers?These are actually just a few of the haphazard, dangerous, and sometimes disastrous responses people have had to the arthropods in their lives. As entomologists, we often try to defend arthropods from people, but how can we also protect people from themselves?” Dr. Ryan Gott’s new article has advice and best practices for talking to the public about arthropods. [The American Entomologist]
Events & News
- Tonight, 8 PM EST, face mite Demodex goes up against the Australian feral camel in the March Mammal Madness AnthropoSCENE bracket! Demodex is the sole arachnid competitor in #2020MMM. Tune in to @2020MMMletsgo for the live updates.
#PruittData
- Act II of #PruittData has commenced. In Science, Elizabeth Pennisi reports that Jonathan Pruitt has lawyered up; some editors and collaborators have gotten letters warning them not to proceed with retractions until his current institution, McMaster University, has finished investigating widespread allegations of data fabrication. American Naturalist editor Daniel Bolnick has also taken down the spreadsheet where collaborators and other community members were tracking papers with possible data anomalies or in the process of being retracted.* [Science]
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* Disclosure: I made minor contributions to the spreadsheet (formatting changes and standardization to make it easier to sort and filter entries). - Science journalist Leonid Schneider reports that in a DM to him, Pruitt took issue with Pennisi’s piece: “I realize the report made it sound like I legally carpet bombed people; that’s not the case…I’m happy for folks to engage in public discourse about my data integrity.” Schneider has posted one of the letters, apparently sent to an editor. Feel free to evaluate whether it comes off as a “gag order” or not. [For Better Science]
- Jeremy Fox comments, “I was most interested in the letter because it reveals how Pruitt will defend himself against allegations of misconduct, at least in one case. He claims that, in at least one case, the data anomalies are not in the data file on which his paper was based, but are only in a different data file that was provided to investigators by mistake.” [Dynamic Ecology]
COVID-19-Related
In case you just crawled out from under a rock, there’s officially a pandemic on. In many countries, the new coronavirus COVID-19 has spread too widely to be contained, and governments and other institutions are now implementing policies attempting to flatten the curve—that is, slow the spread of the virus to lessen the strain on healthcare systems. Schools and workplaces are closing and big events are being cancelled. Yes, this affects the arachnological world as well.
- The Entomological Society of America joint branch meeting scheduled for this week in Oklahoma City, OK has been postponed. (Also, probably not looking good for the Vector-borne Infectious Diseases Conference later this month in Galveston, Texas.) [ESA]
- T̶h̶e̶ ̶A̶m̶e̶r̶i̶c̶a̶n̶ ̶A̶r̶a̶c̶h̶n̶o̶l̶o̶g̶i̶c̶a̶l̶ ̶S̶o̶c̶i̶e̶t̶y̶’̶s̶ ̶a̶n̶n̶u̶a̶l̶ ̶m̶e̶e̶t̶i̶n̶g̶ ̶i̶s̶ ̶c̶o̶m̶i̶n̶g̶ ̶u̶p̶ ̶a̶t̶ ̶t̶h̶e̶ ̶e̶n̶d̶ ̶o̶f̶ ̶J̶u̶n̶e̶ ̶i̶n̶ ̶D̶a̶v̶i̶s̶,̶ ̶C̶a̶l̶i̶f̶o̶r̶n̶i̶a̶.̶ ̶M̶a̶y̶b̶e̶ ̶k̶e̶e̶p̶ ̶a̶n̶ ̶e̶y̶e̶ ̶o̶u̶t̶ ̶f̶o̶r̶ ̶a̶n̶y̶ ̶n̶e̶w̶s̶ ̶a̶b̶o̶u̶t̶ ̶t̶h̶a̶t̶ ̶o̶n̶e̶.̶ Update: Aaaaaand it’s been cancelled. [AAS]
- Online outreach and education is in demand. Nick Keiser is doing Skype a Scientist LIVE on Wednesday, March 18 at 2 PM Eastern. Here’s the Zoom. [Twitter]
Research
- An as-yet-unpublished study from Switzerland finds that populations of the European garden spider (Araneus diadematus) have drastically declined since the 1970s. The authors argue this is because of the overall decrease in their prey, flying insects. This is called a bottom-up trophic cascade—when the collapse of a population affects organisms higher up the food chain. (However, A. diadematus’ cousin Larinioides sclopetarius, which likes building webs near water and artificial lights that attract lots of insects, is doing quite well.) [Preprint 🔓️]
- The wood tiger moth (Arctia plantaginis, until recently known as Parasemia plantaginis) has a bright “danger!” colour scheme, and it’s not just for show—it secretes two kinds of nasty chemicals that protect it from birds and ants, respectively. But will they protect it against spiders? No! Golden silk orbweavers (Trichonephila senegalensis, until recently known as Nephila senegalensis) happily ate the moths, as well as special gelatin capsules treated with the chemicals. (You may wonder why they used a southern African spider with a Holarctic moth. Apparently it’s because T. senegalensis is willing to eat gelatin capsules. Many spiders are pickier eaters and will only eat actual insects.) [Paper 🔓️]
- Spider sex chromosomes are wild. The basic system is X₁X₂0. There are two different X chromosomes; males have one of each, and females have two of each. In some families, there are three or four X chromosomes; in some mygalomorph spiders, there are as many as thirteen. Other systems include X₁X₂Y; X0; XY; and “neo-sex chromosomes”, which seems to be when X chromosomes randomly fuse to become a brand new Y. The number of other chromosomes can vary hugely too. So spider karyotypes are very interesting! We know relatively little about chromosomes in spiders from sub-Saharan Africa, which is why these researchers produced karyotypes for 38 species across 16 families. Read the whole thing to see how African species compare to other family members around the world. [Paper 🔓️]
- One way organic farmers control weeds in fruit orchards is covering the ground around trees with mulch. But how does it affect other natural sources of pest control, like web-building spiders? A study of four different kinds of fruit orchards in South Africa analyzed the makeup of weeds, spiders, and spider prey to test the effects of mulch. Different spiders gravitated to certain types of plants and environments. It turns out that microhabitat, not mulch, has the biggest effect. [Paper 🔓️]
- The great “Are Horseshoe Crabs Arachnids?” debate roils on with a new paper from Team “Nu-uh”. Choosing 27 fossils to calibrate* the molecular clock, they construct a new evolutionary “family tree” of arachnids and their closest relatives. In this scenario, a group of arachnids moved from the sea onto land about 500 million years ago and rapidly split into most of the lineages we know today—mites, ticks, scorpions, spiders, and so on. Arachnids’ older sisters, the horseshoe crabs, remained in the sea.** This would make arachnids “potentially the first carnivorous animals on land”! [Paper 🔓️]
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* Disappointingly, this paper came out a bit too late to fully incorporate Ivan Magalhaes et al.’s recent recommended fossil calibrations.
** Team “They Are Too Arachnids” is salty.
Taxonomy
- This isn’t your average faunistic record paper. These mites were found on larder beetles “colonising experimental pig carcasses” used for a forensic entomology study in the woods of northern Spain. Nothing against good ol’ leaf litter, mind you. But a change every once in a while is refreshing. [Paper]
- These taxonomists have had it up to here with the notable early 20th century German arachnologist and entomologist Embrik Strand. Some select quotes: “He did not illustrate type material from 181 [spider] species and one subspecies and described them only in an insufficient manner”, “This is in remarkable contrast to his usual habit of not indicating where he deposited the type material”, “Strand described these species in his characteristic manner, this means, he sometimes delivered long descriptions but useful diagnostic aspects and comparative discussions regarding other (similar) species were often missing”. Several of the museums Strand’s specimens were stored in were destroyed in World War II, so we literally have nothing to go on. Hence the authors want to strike these species names off the books, freeing us from the meaningless “taxonomic ballast” of the past. [Paper 🔓️]
- The pseudoscorpion Apocheiridium ferum has been found in Hungary for the first time. The only 1mm-long arachnid ranges from Portugal to Uzbekistan, and this find fills in a gap in its distribution. [Paper 🔓️]
- Spiders collected by hand “during short, mainly spring vacation trips” to Albania represent 242 species across 30 families. This brings the total number of species found in Albania to 569, though the authors believe there could be “at least twice as many”. Complete with the lovely photos, this is really selling me on Albania. [Paper 🔓️]
- A new species of uropodid mite, Origmatrachys mahnerti, described from Côte d’Ivoire—the first Origmatrachys species to be found outside the Americas. The paper’s title, “Out of the Neotropical region”, is also a reference to Out of Africa, itself referring to Pliny the Elder’s aphorism “Ex Africa aliquid semper novi”, “always something new out of Africa”. [Paper]
- The orbweavers Larinia chloris and L. lineata are more common in North Africa than previously thought. A new paper lists locations they have been found so far. [Paper 🔓️]
- Several species of aellurine jumping spiders from across sub-Saharan Africa have been put into a new genus, Manzuma. And they’re adorable! [Paper 🔓️]
- Two new Opopaea goblin spiders from Myanmar. Upon looking at the specimen photos I was puzzled; it looked like the abdomen had split along the sides and the inside partly squeezed out, like an edamame bean. I thought maybe it was damage from preservation. But no, Opopaea really do look like that. [Paper 🔓️]
- In the “taxonomy is my passion” file, two new oribatid mites from Thailand: Diplobodes parakanekoi, named for its similarity to D. kanekoi; and Machadocepheus pararachii, named for its similarity to M. rachii. [Paper 🔓️]
As always, thank you for reading, and to Sebastian Alejandro Echeverri for edits and proofreading. Suggestions, corrections, and feedback are welcome! Just drop us a (silk) line at @arachnofiles. 🕷️
Glossary
- araneomorphs: the group of spider families that includes pretty much any ordinary spider — orbweavers, wolf spiders, jumping spiders, sac spiders, etc. — except tarantulas and other mygalomorphs. You’ll sometimes hear araneomorphs called “true spiders” (though likely not by us). Araneomorphs tend to be smaller and shorter-lived, and their fangs swing in towards each other, like tweezers or scissor blades.
- Holarctic: found across the northern hemisphere.
- karyotype: a chart that shows the size and shape of each set of chromosomes an organism has.
- microhabitat: where an animal lives, on a very small scale. E. g. tree trunks, leaf litter, densely branching plants, widely spaced plants, under rocks…
- molecular clock: a way to put dates to evolutionary “family trees” using rates of genetic mutation. If you know how fast a sequence of genetic code changes, you can compare two species’ different copies to see how long ago their common ancestor lived. Fossils give us a way to calibrate molecular clocks by giving us a minimum age for the group they belong to. Here’s a fuller explanation.
- mygalomorphs: the group of spider families that includes tarantulas, trapdoor spiders, and other long-lived, chonky spiders. Their fangs move up-and-down, like a snake’s or a vampire’s. Scientists think that the first spiders to evolve were similar to mygalomorphs. See also araneomorph.
- trophic cascade: when the decline in a population of organisms has rippling effects through the rest of the food web. This can happen with top predators (think wolves in Yellowstone) or organisms at the “bottom of the food chain” (like plankton in the ocean). The scare quotes are there because a food chain is really just one small part of the food web, a non-linear, often reciprocal network of relationships.
- type material: the specimens collected when a species is officially described. They are preserved—for squishier creatures like spiders, that means popped in a vial of ethanol; for beetles, butterflies, etc., pinned on a card—and stored in a museum as the official representative of the species. Kind of like how up till recently the kilogram was a literal hunk of metal in France.
