Arachnews: May 31, 2020

Your w̶e̶e̶k̶l̶y̶ r̶e̶g̶u̶l̶a̶r̶ periodical roundup of arachnid art, news, and science.

Neville Park
Jun 4, 2020 · 10 min read

After a long hiatus, we’re back! We are catching up on May’s news and will be splitting up the month into at least two parts. In this edition: #BlackLivesMatter, spider art, newly minted doctors, sexual warfare, climate change and cannibalism, tailless whipscorpion senses, and more.

Terms in bold are defined in the Glossary at the end of the post.


Systemic racism and police brutality scar all parts of our society, including science. We are a small organization with a relatively narrow focus, but recent events are too important to ignore. It would be disingenuous and unethical to just talk arachnids and pretend nothing else is going on. In the past week and a bit:

  • In New York City’s Central Park, a white woman threatened to call the police on a Black birder who asked her to leash her dog. Not just any Black birder — Christian Cooper, who sits on NYC Audubon’s Board of Directors. His recording of the encounter went viral. Many Black birders, as well as nature-lovers, naturalists, and scientists in general, spoke out in the news and social media about the dangers of being out in nature while Black.
  • The next day, outside a corner store in Minneapolis, a white cop killed a Black man, George Floyd, by kneeling on his neck. A bystander’s video went viral. Protests against police violence erupt into riots, with the police station and nearby buildings and businesses set on fire and looted. Demonstrations spread across the US and the world — not just in solidarity with Minneapolis, but also against local police brutality against Black residents. Police respond with repeated and deliberate violence, using batons, tear gas, and bullets to attack not just protesters but medics, bystanders, and journalists from major media outlets.

In response, various institutions and organizations are issuing statements condemning racism and pledging support for Black members and groups. Some specifically arachnological ones:

  • The American Arachnological Society: “Black members of our society, as a community the American Arachnological Society supports you…I also reach out with humility acknowledging that we can do more to wide and smooth the path into and through arachnology to make participation in our beloved field more accessible for all.” As part of this statement, AAS has created an anonymous survey for arachnologists to share “insights or detailed examples of ways in which racism has affected your path in arachnology, and/or ideas for how we can make sure the arms of inclusiveness in our society are opened as widely as possible.”[Email] [Survey]
  • The International Society of Arachnology: “There is no single image of an arachnologist…We need thousands of different eyes in a thousand different places watching and learning about our favourite creatures. We need every colour in the spectrum to reveal nature fully.” [Twitter]

Under the banner @BlackAFinSTEM, a group of Black scientists and naturalists have organized Black Birders Week, a currently ongoing series of social media events. Do check out #BlackInNature and subscribe to this Twitter list for more. [CNN, LiveScience, Audobon, Inverse, etc.]

Art & Social Media

Two absolutely wild threads:

  • Tone Killick discovers a wolf spider mother carrying two egg sacs, and tries to get to the bottom of the mystery. He also summarizes his observations in long form here. [Twitter]
  • In a garage science experiment gone wrong, Dr. David Boyce inadvertently breeds a giant, hyper-cannibalistic house spider. [Twitter]

Education & Outreach

  • In a livestream for Wired, which I can’t embed here because Facebook is a butt, arachnologist Lauren Esposito introduces their favourite arachnids and insects behind the scenes at the California Academy of Sciences. [Wired] [Facebook]
  • Allan Archer reviews Erica McAlister’s The Secret Life of Flies and Helen Smith’s On the Margins, which is about the rare fen raft spider (Dolomedes plantarius) in England. [YouTube]
  • On Twitter, Jolanta🕷️ explains how to gently reduce an arachnophobic friend’s fear of spiders and turn fear to fascination. Do read the replies for feedback from people who are, or were, afraid of spiders. [Twitter]
  • Our own Sebastian Alejandro Echeverri goes on Maya Higa’s Conservation Cast to talk spiders, with donation proceeds going to the Xerxes Society for Invertebrate Conservation. [Twitch]
  • For International Endangered Species Day, Mike Rix writes about the plight of the Kangaroo Island assassin spider (Zephyrarchaea austini), feared extinct after its habitat was wiped out by wildfire: “Its continued existence remains unlikely at best.” [Queensland Museum Network Blog]

News & Events

  • If any international students are interested in doing a spider-related PhD at Macquarie University in Sydney, Australia, do contact Marie Herberstein; applications for scholarships are open until July 31, 2020. [Twitter] [Macquarie University]
  • It’s flying (ballooning) spider season in Houston, as baby spiders lift off to find new places to live. (The article is only mildly alarmist.) [Click2Houston]
  • #PruittData: a correction has been issued for this 2013 paper after the authors found anomalies in data curated and partly collected by the last author, Jonathan Pruitt. See Nick Keiser’s thread for more context. [Behavioral Ecology]

Spider Doctors

Since last I wrote, two of #SpiderTwitter’s own have now finished their PhDs and are officially Doctors:

  • Dr. Shakira Quiñones-Lebrón, whose thesis is on extreme sexual size dimorphism in golden silk orbweavers. Why are males so tiny? Does it have anything to do with sexual cannibalism? [Thesis]


  • This recent paper in Conservation Biology, “Effects of amusing memes on concern for unappealing species”, is surely an Ig Nobel shoo-in. The authors studied Polish memes about proboscis monkeys and spontaneous conservation crowdfunding, but this is clearly applicable to other, less charismatic animals around the world (such as many of our beloved arachnids). Alas, I’m sorry to say there are no example memes in the paper. [Paper] [Sci‑Hub]
  • A preprint from Stefano Mammola and others finds that Italian media coverage of spiders is overwhelmingly alarmist and error-filled, “and in virtually none was an expert consulted”. Unsurprising, sadly. [Preprint 🔓️]
  • The spider Micaria sociabilis mimics the ant Liometopum microcephalum as protection from predators—and it actively follows the trail of that species and avoids following another (Lasius fuliginosus). It’s not picking up on scents, which isn’t surprising; that’s more a specialty of ant-mimics that prey on their models. But what chemical cues it’s using are so far unknown. [Paper 🔓️]
  • A new preprint from the Sharma lab sheds light on arachnid eye development, a subject still in its infancy. They compare the eye genes expressed in two closely related cave-dwelling amblypygids, Charinus ioanniticus and C. israelensis. C. ioanniticus has normal eyes, but C. israelensis has lost them. During C. ioanniticus’ embryonic development, two genes (Pax6A and OptixA) were expressed much more often than in its eyeless sister species. [Preprint 🔓️]
  • Related (and including the lead author of the previous paper): how does the amblypygid Charinus asturius use its antenniform (antenna-shaped) legs while hunting? Most of what we know about antenniform legs comes from Heterophrynus, an amblypygid from a different family, and scanning electron microscope images show that C. asturius’ have a slightly different array of sense organs. The next step would be to compare the hunting behaviour of amblypygids with normal and removed or disabled antenniform legs—but that will have to be another study. [Paper] [Sci‑Hub]
  • While studying Australian pirate spider spinnerets for this paper (included in the previous Arachnews), the authors found a weird mutant specimen! It had an extra spinneret, a silk gland in the wrong place, and three wonky pores. They think the abnormalities were caused by extreme temperature fluctuations (both high and low), which have been known to cause extra spinnerets in other spiders. [Paper] [Sci‑Hub]
  • What’s the best way to trap spiders for collecting? The traditional way is the pitfall trap (a container buried in the ground), but some studies have found better results from ramp traps (a ramp leading up to a container). One can also tie containers to tree trunks and branches to catch tree-dwelling spiders. Researchers compared four types of traps in action on a mountain in North Macedonia. They found pitfall traps were by far the best, but granted that other types are useful in certain situations—e. g., when digging a hole isn’t an option, or for catching exclusively tree-dwelling spiders. [Paper] [Sci‑Hub]
  • Climate change is selecting for larger and more fertile Arctic wolf spiders (Pardosa lapponica), but the benefits of these adaptations may be cancelled out by an increase in cannibalism. That is, the biggest wolf spiders are eating their younger competitors. See ScienceAlert’s coverage here. [Paper] [Sci‑Hub]
  • Sexual selection doesn’t stop at sex. Female St. Andrew’s Cross spiders (Argiope keyserlingi) aren’t picky about who they mate with. But when you look at which males’ sperm actually gets used to fertilize their eggs, patterns emerge! Males that performed longer courtships and copulated with the female longer were more likely to have their sperm used by the female. Also, very weirdly, females seemed to prefer males that had been irradiated to reduce their fertility, used as controls in the experiments. [Paper] [Sci‑Hub]
  • Many male harvesters have exaggerated, weaponized body parts used in fighting each other over females. And New Zealand’s harvesters have the most extreme and diverse weaponry of all. In the harvester Forsteropsalis pureora, males come in three forms: small with itty-bitty jaws, big with long jaws, and big with fat jaws. Why did these 3 forms evolve, and how do they interact with each other? Read on for what happened when they put ’em in a jar and made ’em fight. [Paper 🔓️]
  • What if you could detect pesticide resistance in spider mites (Tetranychus urticae)…in real time? Researchers in Japan have developed a new, faster way to test for gene mutations that makes spider mites resistant to three different pesticides. [Paper] [Sci‑Hub]


New species, species found in new places, “family trees”, surveys, and so on.

  • Three new slender long-jawed orbweavers (Tetragnatha) from around the world: T. megalocera from Brazil, T. renatoi from Venezuela, Argentina, and Brazil; and T. chiyokoae from China and Japan. [Paper] [Sci‑Hub]
  • Fun fact: you can tell what Caribbean island a spiny-backed orbweaver (Gasteracantha cancriformis) is from by the number of spines it has! Oddly, these spiders’ number of spines or colour schemes don’t correspond to genetic similarity. More revelations in this new paper. [Paper 🔓️]
  • A cute little harvester, Ethobunus oaxacensis, described from Oaxaca, Mexico. [Paper 🔓️]
  • A new caeculid mite, Caeculus veracruzensis, found in the soil in Veracruz, Mexico. I eagerly await the paper’s appearance on Sci-Hub, as caeculids are very interesting-looking. [Paper]
  • A new database of spiders from Spain and Macaronesia catalogues not only their physical traits, but also information like whether they’re ground dwellers or arboreal, nocturnal or diurnal, and native or introduced. [Paper 🔓️]
  • Two new spiders in the family Phyxelididae—yeah, I hadn’t heard of it either. Most species are found in southern and eastern Africa, with some in Turkey(!) and Indonesia(!!). Wild. Anyway, the new species are Xevioso cepfi, from Mozambique, and X. megcummingae (named after the collector, naturalist Meg Cumming), found in Zimbabwe and Malawi. [Paper 🔓️]
  • This surely can’t be the first time anyone’s found red velvet mites in Saudi Arabia?! Several species are reported from the country for the first time, as well as a brand new one, Allothrombium monosolenidion. [Paper]
  • A new flat mite, Cenopalpus umbellatus, was found on Rhaphiolepis indica var. umbellata in Japan. There’s also an identification key for all 70 Cenopalpus mites. [Paper 🔓️]
  • A whole new genus of goblin spiders, Promolotra, is described from Myanmar. It includes two new species, P. shankhaung and P. hponkanrazi, named after the places they were found. [Paper 🔓️]

Thank you very much for reading! I’m grateful to Catherine Scott and Sebastian Alejandro Echeverri for feedback and editing. We hope to get back to a regular schedule and chip away at the considerable backlog. Suggestions are always welcome; just drop us a (silk) line at @arachnofiles. 🕷️


  • model: A word with many different meanings in science. In the case of mimicry, the model is the animal or object that the mimic is pretending to be. In the case of statistics (“a statistical model” or “models show that…”), a model is a computer program or script that compares observed data with many possible rules that could explain that data, and makes some conclusions on which rules are the best explanations.
  • preprint: A draft of a research paper that is made available to the public before the research has gone through peer review. Preprints allows scientists to get early feedback on their ideas, but should not be viewed with the same confidence as a published paper.
  • sexual selection: A method of evolution selection that selects for traits and behaviors that increase an individual’s likelihood of mating, and the number of offspring they produce.


Arachnids are fascinating.

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