Arachnews: May 12, 2020

Your regular round-up of all things arachnid.

Neville Park
May 12, 2020 · 10 min read

Welcome back, everyone. I wish I could say our hiatus was because of These Uncertain Times, but honestly it was just plain old depression. In this edition: fascinating observations, enchanting arts and crafts, news about venom research, organic pesticides, educational videos, and more.

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

Art & Social Media

This striking solfugid was found in Bengaluru, India by iNaturalist user harshithjv.
A Caerostris bark spider photographed by Colin Hutton.
A fascinating thread by Tone Killick on an unusual observation.
An amazing papercraft amblypygid from Twitter user 紙切虫.
A lovely “spider nest” embroidery by Adam Pritchett.
  • Buenos Aires’ Museum of Modern Art has uploaded Tomás Saraceno: Cómo atrapar el universo en una telaraña (How to entangle the universe in a spiderweb), a book on the artist’s installations there. One involved a colony of thousands of social spiders taking over a gallery; another translated the vibrations of a golden silk orbweaver’s web into music. (Previously.) [Issuu]
“Tarantula tea party” girl is now 10, still loves tarantulas. • /u/DefiantButterscotch6
  • Years ago, a photo of a little girl hosting a tea party for three tarantulas racked up hundreds of thousands of likes and reblogs on Tumblr (probably originally from Arachnoboards). Recently her mother posted an update to /r/spiderbro: “Carly is now 10 and she has had many tarantulas since her tea party.” Read more about the famous photo in the thread. [Reddit]

Education & Outreach

  • [In ASL] In this quick video for Atomic Hands, Barbara describes all the different kinds of webs spiders make. [YouTube]

News & Events

The Australian bushfires pose a grave threat to shallow-burrowing trapdoor spiders • Leanda Mason
  • The recent Australian bushfires devastated Western Australia’s Stirling Range National Park, the home of ancient, slow-growing and little-understood trapdoor spiders. “It is too early to know if any species have been wiped out — or are under existential threat — after the latest fires. Detailed surveys will have to be carried out and it could take years to understand the full impact.” [The National]
  • The tick monitoring project eTick.ca is rolling out in Nova Scotia, Newfoundland and Labrador, and Saskatchewan. It’s already up and running in Quebec, Ontario, and New Brunswick. Users can submit photos of ticks they find to be identified by experts and added to a public database. [Halifax Examiner]
  • Calling all Nebraskans! Eileen Hebets reports that a UNL PhD student cannot get to her field site due to COVID-19-related restrictions and needs new locations to study the wolf spider Schizocosa retrorsa. Please spread the word. [Twitter]
  • For PNAS, Amy McDermott reports on the growing interest in developing drugs from animal venom. Glenn King’s tarantula venom research gets a mention, as well as tozuleristide, a diagnostic drug derived from scorpion venom that’s currently in clinical trials. [PNAS]
  • Zoe Cormier’s article for BBC Future covers much of the same ground—why venom is so promising, the recent technological advances that have made research more viable, and new drugs in the pipeline. There’s also a shout-out to ArachnoServer, a spider venom database. [BBC Future]
  • The joint meeting of the Entomological Society of Canada and the Entomological Society of Alberta, originally planned for this October in Calgary, has been cancelled. [JAM2020]

A couple of general science-related items that could use arachnologists’ contributions:

  • The journal Behaviour is planning a special issue on “Anecdotes in Animal Behaviour”. “Narrative accounts of unique behaviours are on a stark decline…We hereby invite scholars who have anecdotal evidence of unique behaviour in any species, to submit these as a commentary to Behaviour.” [Behaviour]
  • As a newcomer to scientific literature, I was thrilled to find some papers included short, jargon-free “lay summaries”—then shocked to learn that they are routinely required but almost never published. The website WikiFindings is an attempt to remedy that, providing headline-length, plain-language descriptions of newly published research. The site is a few years old, but could use help getting off the ground. [WikiFindings]

Research

  • Arthropocalypse research: a large new meta-analysis, spanning 166 surveys over 93 years, paints a more complex picture of arachnid and insect population declines. Overall, land-dwelling arthropods are declining 9% per decade; losses are accelerating in Europe but have largely flattened off in North America, and seem to be associated with urbanization. Freshwater arthropods are increasing by 11% a decade—possibly driven by environmental protections like the Clean Water Act, deindustrialization after the collapse of the Soviet Union, warming temperatures, or other factors. However, the available data isn’t representative of the whole world. There’s little data from places outside North America and Europe, many of which are experiencing much bigger changes; and freshwater accounts for only a fraction of the earth’s surface. One of the biggest takeaways should be that these population changes vary hugely by location, and generalizations about worldwide trends might not be that helpful. For more context, see coverage in the Guardian. [Paper] [Sci‑Hub]
  • Ticks took a gene from bacteria for an anti-microbial toxin that protects them from pathogens they might encounter on a host’s skin — like staph — but not their own bacterial symbionts, like Borrelia. [Preprint 🔓️]
  • A soft tick (Ornithodoros hasei) found on a bat from Argentina was carrying Rickettsia bacteria related to species that cause spotted fever. (Don’t freak out; it’s one tick on one bat, out of five that had ticks on them, out of 143 bats searched.) [Paper] [Sci‑Hub]
  • Can you make a long-horned tick vaccine based on proteins found in their muscles? (No.) [Paper 🔓️]
  • Is a new species of the predatory mite Neioseiulus californicus evolving in China? Nope, despite looking different, the Chinese population is still the same species as the one from California. [Paper]
  • Spinosad, one of the “natural”* pesticides that’s okay to use in organic farming, disrupts orbweavers’ web-building. The authors note that this is a small case study and they couldn’t find enough spiders and webs in the unsprayed control area, so take the results with a grain of salt. [Paper] [Sci‑Hub]
    ________
    * The active ingredients come from fermentation of a soil bacterium. It works by messing up arthropod nervous systems. As with other pesticides, bugs can develop resistance to it.
  • Kind of related: here’s a study on another “natural” pesticide, an acaricide based on oxymatrine, an alkaloid from the legume Sophora flavescens. It’s pretty good at killing Oligonychus ilicis, spider mites that are major pests of coffee trees. However, we still don’t know possible negative side effects on other organisms, or how well it will work in the field. [Paper] [Sci‑Hub]
  • Some tarantulas seem to be able to adjust their metabolism to keep from dehydrating in hot, dry conditions. A recent study compared two species of tarantula from the Uruguayan Pampas. Grammostola quirogai’s habitat is closer to the ocean and experiences climate fluctuations caused by El Niño, while G. anthracina lives in a more temperate region. The authors predicted G. quirogai would be better at adjusting to adverse conditions. However, in experiments neither of them really showed much change in metabolism or water loss rate. Maybe tarantulas that don’t live in deserts didn’t have to evolve those mechanisms. [Paper] [Sci‑Hub]
  • Ticks are known for “questing”, a behaviour where they climb up plants and sit around waving their arms, o̶f̶f̶e̶r̶i̶n̶g̶ ̶f̶r̶e̶e̶ ̶h̶u̶g̶s̶ looking for passing animals to latch on to. Temperature, humidity, and wind all affect how high ticks climb when they quest, as these experiments with Gulf Coast ticks (Amblyomma maculatum) show: “A. maculatum nymphs randomly select stems to quest upon and climb upward until environmental conditions are prohibitive/ideal.” [Paper] [Sci‑Hub]
  • Can the modern* male spider have it all? An otherwise pretty ordinary Australian pirate spider, Australomimetus maculosus, is unique in that the male spiders’ spinnerets have spigots for making cylindrical silk. Nearly all araneomorph species have cylindrical silk spigots, but it was a general rule that only females had them…until now. Female spiders use cylindrical silk for making egg sacs. Do males use cylindrical silk for anything? We’ll have to find out. [Paper 🔓️]
    ________
    * By which the authors mean araneomorph. Araneomorphs are often referred to as “true” spiders, which is misleading because ALL SPIDERS ARE VALID. I am not sure “modern” is an improvement, though.

Taxonomy

Where in the world did golden silk orbweavers come from? A new study traces their history through evolutionary time, from their origins in the West Burma Block to a worldwide distribution. • Turk et al 2020
  • The golden silk orbweavers and their closest relatives— either family Nephilidae or subfamily Nephilinae, depending which side of the ongoing heated debate you fall on—are found all around the world. But where did they come from? The oldest fossils that might be nephilid spiders come from amber from Myanmar, but Africa has the greatest diversity of living species. Team Nephilidae constructed a family tree using genetic data and found that they probably originated from the West Burma Block, a chunk of land that split off from the supercontinent Gondwana at some point in the Cretaceous. [Paper 🔓️]

Americas

  • North-east Brazil’s Caatinga is a unique dry scrubland increasingly threatened by climate change and human activity. And until now, we didn’t know anything about which pseudoscorpions lived there! The authors found nine species, but suspect they’re only scratching the surface. [Paper 🔓️]
A male Leptostygnus yarigui. Look at those massive chelicerae! • Garcia and Villareal 2020
  • A new species of harvester, Leptostygnus yarigui, found in the Andean cloud forest of Colombia. It’s named after the Yariguí, the Indigenous people who used to live there before European settlers, and later the oil industry and the state, destroyed them. If you didn’t expect taxonomy to veer into discussion of genocide, boy are you in for a surprise.[Paper] [Sci‑Hub]
  • Researchers in Colombia studied how two tick species, Amblyomma mixtum and Rhiphicephalus sanguineus, make sperm cells. This is important not just because it sheds light on tick reproduction, but because the different ways sperm cells form could be a way to tell identical-looking species apart. [Paper] [Sci‑Hub]
  • Five new species of Pavania phoretic mites found on scarab beetles in French Guiana. [Paper]

Europe

  • A new list of spiders from Molise, Italy includes 98 species across 21 families, 48 of them recorded for the first time. [Paper 🔓️]
  • New descriptions of the life stages of Fuscozetes coulsoni, an oribatid mite from Svalbard, Norway. [Paper]

Africa

  • Two new species of oribatid mites from Madagascar. [Paper]
Male (A) and female (B) Lepthercus engelbrechti. Rios-Tamayo & Lyle 2020
  • Lepthercus, a genus of funnel-web trapdoor spiders from South Africa, gets a second look after more than a hundred years. This brings nine new species, which seem to be divided into two distinct branches of the “family tree”. Also, the family Nemesiidae is misspelled as “Nemessidae” three times but otherwise I’m sure the paper is fine. [Paper] [Sci‑Hub]

Asia

  • Pediculaster mites are pretty cool—they eat fungi, and females come in two distinct forms. One form travels by phoresy (hitching rides on flies), the other stays put. Three new Pediculaster species have been found in Siberia. [Paper 🔓️]
  • The sac spider species Clubiona milingae was first described based on a single specimen. Luckily, there’s more out there. The description can now be fully fleshed out, based on specimens collected from Hainan Island, China. [Paper 🔓️]
  • “To the best of our knowledge, this study is the first to propose the term ‘flower-visiting spiders’.” This two-year survey catalogued the spiders in the gardens of a large park in Xiaogan City, Hubei, China (mostly crab spiders, on tulips). [Paper] [Sci‑Hub]

Thank you very much for reading! And thanks to Sebastian Alejandro Echeverri for the edits. Additions, corrections, and other feedback is always welcome; just drop us a (silk) line at @arachnofiles. 🕷️

Glossary

  • acaricide: a pesticide against mites and ticks.
  • alkaloid: a kind of nitrogen-based compound. Many plants produce alkaloids—maybe to make themselves taste bad to predators, maybe as a byproduct of metabolism, maybe for other, mysterious reasons. We don’t really know.
  • 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.
  • meta-analysis: a study that compiles and analyzes data from lots of previous studies. Meta-analyses can help identify larger trends that smaller-scale studies can’t.
  • 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.
  • phoresy: hitching a ride on another animal. Mites and pseudoscorpions are especially known for this behaviour.

Arachnofiles

Arachnids are fascinating.

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