Arachnews: January 6, 2020
Art, news, and science about all things arachnid.
Published in
12 min readJan 6, 2020
Welcome to the first weekly Arachnews! Because there was just too much goodness for a monthly digest. Still a bit of a hefty read as there’s a backlog of articles, so grab yourself a cup of tea before digging in. A new feature: technical terms bolded in the text are defined in a glossary at the very end.
Art & Social Media
Social Media
- [Spanish] An image circulating recently in Argentina claims to show the differences between harmless and medically important scorpions. @Arachno_Cosas shares the facts in a Twitter thread.
- “Pygmy Possums quickly took up residence in the nest boxes we erected in restored habitat at our Monjebup North reserve in southwest WA. What we didn’t expect were the large colonies of social spiders that also moved in!” Media coverage: ScienceAlert, Republic, ABC.
- Javed Ahmed has started a Discord for Indian spiders. Get an invite here.
You’re big, they’re small, and they want to live. So they act out in a way they think will help their survival.
- Kali Clark (@LycosidaeLove) explains why spiders are defensive, not “aggressive”.
- On Reddit, this Sydney resident shared a photo of a huntsman spider having a very bad day.
- Mystery social spiders in Cameroon, possibly Paraplectana. Anyone know?
Photography
Video
Art
Education & Outreach
- Piter Boll profiles the lovely linyphiid Florinda coccinea for Earthling Nature.
- Wayne Maddison reflects on the use of 95% ethanol to preserve spider specimens, which is currently better for recovering DNA but makes specimens more brittle and distorted.
- [Swedish] Children’s magazine Eos has an article on Helsinki’s LIBRe Lab’s recent Spider Sorting Day.
- Learn about the largest pseudoscorpion in the world, the critically endangered Garypus titanius of Ascension Island.
- Tone Killick has created a video showing Steatoda nobilis, the noble false widow, from egg to hatching.
- Gustavo de Miranda has collected almost all the literature on Amblypygi — over 260 years’ worth! — in a Zotero list.
Events & News
- A lovely obituary of Australian arachnologist Barbara York Main, as part of “The Lives They Lived”, the NYT’s year-end notable obituaries.
- Arachnologist Eileen Hebets of the University of Nebraska has been named a 2019 AAAS fellow “for distinguished contributions to behavioral and evolutionary biology, particularly animal communication, sensory biology and mating strategies, as well as science communication outreach and informal science learning.”
- Catherine Scott, known for going viral livetweeting spider mating, the Great Black Widow Race, Recluse or Notl, and more, is finally a Spider Doctor! She celebrated with a spider cake and getting an awesome western black widow tattoo. She’s now doing a postdoc at Kirk Hillier’s lab at Acadia University, Nova Scotia.
- Venom researcher Volker Herzig is getting his own lab at the University of the Sunshine Coast, Australia.
- The University of Veracruz’s Dulce Rodriguez Morales has won the “Arte, Ciencia, Luz” prize for research on how insects perceive crab spiders on flowers.
Research
Silk
- The southern house spider (Kukulcania hibernalis) can produce a stronger and more complex three-dimensional capture thread simply by moving pairs of spinnerets at different speeds! This lets it capture more prey than smaller species with more fibrous silk. [Paper 🔓️]
- Why silk (including spider silk) becomes stiffer as it gets colder. [Paper 🔓️]
- An artificial spider silk, about as tough and stretchy as the real thing, has been produced “by the water-evaporation-induced self-assembly of hydrogel fibre made from polyacrylic acid and silica nanoparticles”, which I’m not even going to pretend to understand. [Paper 🔓️]
- Another new spider silk-like fibre incorporates hydroxyapatite, a mineral in bone, to create extra-tough tiny ropes. [Paper] [Sci-Hub]
Pest control
- In tick bait boxes, acaricide rubs off on mice lured in by food, killing ticks that could pass diseases on to humans. They’re effective in the short term, but what are the long-term effects of providing a bountiful food source for the mice? [Paper 🔓️]
- A single spraying of the synthetic pyrethroid pesticide bifethrin in spring, before tick season really gets under way, is surprisingly effective. [Paper] [Sci-Hub]
- Can farmers keep more spiders in their vineyards by pruning less or using fungus-resistant grapes? [Paper 🔓️]
Heat stress
- The spider mite Tetranychus evansi is a major pest of crops in the nightshade family, like tomatoes, potatoes, eggplant, and tobacco. It’s voracious, resilient, and it’s gonna love global warming. [Paper 🔓️]
- Related: on the upside, the closely related Tetranychus ludeni can’t tolerate either cool or very hot weather, limiting the regions it can get established in. [Paper 🔓️]
- The name Sicarius thomisoides or “sand recluse spider” might not ring a bell, but you probably know them. They are bad at hiding, and they are wimps. Yeah, those guys. Anyway, they live in the deserts of Chile, which are hot during the day and cold at night. However, these nocturnal predators like it cool during the day and hot at night. [Paper 🔓️]
- Adult sheetweb weavers (Hylyphantes graminicola) stand the heat better than spiderlings — but why? This paper looks into what their enzymes do under heat stress. [Paper 🔓️]
Hunter & hunted
- Acarodomatia — literally “mite houses”, little pouches or tufts on plant leaves that serve as shelter for mites that prey on the plant’s pests — have been found on 75-million-year-old plant fossils from Utah, by far the oldest yet. [Paper 🔓️]
- On “a tick-infested island in southwestern Finland”, researchers find signs that the parasitic wasp Ixodiphagus hookeri is preying on castor bean ticks (Ixodes ricinus). [Paper 🔓️]
- The spartaeine jumping spider Phaeacius was observed preying on a two-tailed spider (Hersilia) in Karnataka, India. “Since Hersilia spp. are fast-moving predators that surround themselves with trap lines for the detection of prey, this is no mean feat.” [Paper 🔓️]
- Usually, spiders that use webs to capture prey will run out, grab it, and wrap it up. Occasionally, they do something else: gathering in the web to pull the prey towards them, like a fisherman reeling in a fish. Why do they do this? Here’s a study exploring the behaviour in the orbweaver Verrucosa arenata. [Paper] [Sci-Hub]
- It’s the predatory mite Hunger Games: three species of phytoseiid mites pitted against each other. Without their main prey (spider mites) available, who eats whom? [Paper]
- By hunting together, social spiders can capture bigger prey than they’d be able to catch alone. At least, that’s how it seems to work for little spiders like Anelosimus. But the less social species of Stegodyphus are actually bigger than their social cousins and can already catch anything they want. Here’s an intriguing hypothesis to explain this apparent contradiction. [Paper] [Sci-Hub]
Mating, reproduction, & parental care
- Neobrettus tibialis jumping spiders in West Bengal, India have been observed eating their own eggs; eating mysterious flecks on the silk covering their eggs; and mating while guarding their brood, all very interesting behaviours. [Paper 🔓️]
- Title of the year? “Another one bites the gift: sexual behaviour in a Trechaleoides species”. The paper describes Trechaleoides keyserlingi males offering silk-wrapped “gifts” to prospective mates. [Paper]
- The elaborate dance of peacock spider Maratus aquilus. [Paper 🔓️]
- A spider mite (T. urticae) mother’s social environment — e. g. whether she shares a plant with a population of rivals or kin — affects her sons’ mating strategies (“fighter” vs. “sneaker”). A novel aspect here is that T. urticae are arrhenotokous: fertilized eggs are female, unfertilized eggs are male. So a female spider mite’s sons inherit from her alone. [Paper 🔓️]
Evolution
- Today, jumping spiders in the Habronattus tarsalis species complex live in isolated oases in the deserts of the western United States, but thousands of years ago their habitats were connected by ancient lakes. These environmental changes have left traces in their genetic history, showing evidence of ephemeral speciation. [Paper] [Sci-Hub]
- Can natural selection work on the level of groups, not just individuals? In Anelosimus studiosus social spiders, where females can choose to stay with their colony or go off to found their own, multiple levels of natural selection may be operating. A group of researchers created an evolutionary simulation to test the idea. [Paper 🔓️]
- Related: surprisingly, A. studiosus has genes for boldness! [Paper 🔓️]
- Eurypterids — extinct chelicerates commonly called “sea scorpions” — had unusual compound eyes that are strikingly similar to those of modern-day horseshoe crabs. [Paper 🔓️]
Theses
- Amblypygids can learn to use combined scent and tactile cues to find their way back to their shelters! [Paper 🔓️]
- Here’s how to mess up their brains to test that. [Paper 🔓️]
Miscellaneous
- Not arachnid-specific, but relevant: only a fraction of arthropod specimens in North American collections are identified and digitized. To track biodiversity, we not only need to be digitizing faster but collecting more. [Paper 🔓️]
- Unsurprisingly, spider-eating spiders’ venom works best on spiders; ant-eating spiders’ venom works best on ants; and general bug-eating spiders’ venom worked the same with both. [Paper 🔓️]
- Peptides from the venom of the buthid scorpion Hottentotta jayakari could be used to treat Dravet syndrome, a rare kind of childhood epilepsy. Obligatory IN MICE. [Paper 🔓️]
- It’s important to learn where scorpions live, both to avoid dangerous encounters and to protect endangered species. Researchers in Iran are combining data on climate, land use, and soil types to predict where burrowing scorpions are likely to be found. [Paper] [Sci-Hub]
- DNA barcodes can make it easier to identify what animals are eating, but distinguishing the predator’s DNA from the prey’s can be difficult—especially when the predator feeds on its close relatives, as happens with spiders. Researchers have developed a new PCR primer, NoSpi2, to barcode whatever Pardosa wolf spiders are eating. [Paper 🔓️]
- Karyotypes for two Turkish buthid scorpions, Hottentotta saulcyi and Buthacus macrocentrus. The authors mention advancing our understanding of “one of the most important and dangerously venomous members of the family Buthidae” but, troublingly, do not mention which one it is. 🤔️ [Paper 🔓️]
Taxonomy
Americas
- A new recluse species, Loxosceles tenochtitlan, found in the heart of Mexico City! [Paper 🔓️]
- A survey of the spiders of El Triunfo Biosphere Reserve, Chiapas, Mexico. [Paper 🔓️]
- Amilaps mayana is a new genus and species of jumping spider belonging to the Lapsiini, a Central and South American jumping spider tribe whose diversity is still being explored. [Paper 🔓️]
- The Central American scorpion Centruroides mahnerti is actually just an immature female C. koesteri. [Paper 🔓️]
- A checklist of the pseudoscorpions of Colombia—65 species, with many more yet to be found. [Paper] [Sci-Hub]
- Almost 80 years after it was last seen, the cosmetid harvestperson Eulibitia ectroxantha has been found again (and redescribed) in Colombia. [Paper] [Sci-Hub]
- A new solifuge from Brazil, Gaucha cabriola. The name comes from a legend originally from Portugal: “The ‘Cabriola’ goat throws fire and smoke through her eyes, nose and mouth at anyone wandering deserted streets on Friday nights. Also, it enters the houses through the roof or door, looking for spoiled and mischievous boys to become its meal. So luckily, there is no material evidence of its existence, and it only lives in the local folklore and in this solifuge species name.” [Paper] [Sci-Hub]
Africa
- The stunning Phinda button spider (Latrodectus umbukwane) is a newly described widow spider from South Africa. (You may recall a blog post about its discovery from February 2019’s Arachnews.) [Paper] [Sci-Hub]
- An “amazing” new flat mite, Phytoptipalpus occultuae, found under hook-thorn bark in South Africa. What’s so amazing about it? The adult females’ very short back legs. Acarologists, everyone. [Paper 🔓️]
- A survey (with identification key) of the spiders of Assiut Governorate, which spans a stretch of the Nile in Upper Egypt. [Paper 🔓️]
- In 2014, researchers studying the castor bean tick (Ixodes ricinus) in the Mediterranean and North Africa realized some belonged to a different species, which they called Ixodes inopinatus. So for the past several years, people have been double-checking for populations of I. opinatus they might have overlooked or misidentified. In Tunisia, I. opinatus and I. ricinus have been living side by side. [Paper] [Sci-Hub]
Europe
- A survey of the many, many mites of a broadleaf forest in Norway. [Paper]
- A new species of plant-eating mite, Brevipalpus sulcatus, found in native ivy from the Azores archipelago. [Paper] [Sci-Hub]
Asia
- God, I love weird cave spiders. A new genus of cave-dwelling dysderids, Kut, from Turkey. [Paper 🔓️]
- A new stilt-legged soil mite, Tycherobius banehiensis, found in Kurdistan Province, Iran. [Paper]
- A new predatory mite, Scutascirus hechiensis, from China. [Paper]
- Many years ago, some scientists named a Chinese sac spider Clubiona transversa. Unknown to them, the name was already taken. Since then, the other C. transversa has been renamed (to C. maritima), but using the name is still against the rules. A fitting new name: Clubiona zhangyongjingi, after one of the guys who found it in the first place. [Paper 🔓️]
- Najadicola loeiensis is a new water mite that parasitizes freshwater mussels in Thailand. [Paper 🔓️]
- A survey of wolf spiders in the Philippines. [Paper]
- A new ray spider from Japan, Wendigardla ruficeps. [Paper 🔓️]
- Coelotine funnel-weavers from Kyushu previously identified as Iwogumoa insidiosa are actually I. songminjae; a spider described as Coelotes iyoensis is just the male of C. mohrii. [Paper 🔓️]
Oceania
- Three new Corambis jumping spiders from New Caledonia, including C. jacknicholsoni. [Paper 🔓️]
Thanks to Sebastian Alejandro Echeverri for helping with this edition of Arachnews. Corrections, ideas, and items are welcome! Seriously, send in your papers and art and stuff. Leave a comment or drop us a (silk) line on Twitter at @arachnofiles.
Glossary
- acaricide: tick-killing pesticide.
- DNA barcodes: differences in DNA that can be used to tell two species apart quickly and reliably. These can be anything from how many bits the DNA gets chopped into when digested by a certain enzyme, to the actual sequence of bases.
- chelicerate: a member of the subphylum Chelicerata, the group of arthropods that consists of arachnids and a couple of weird outliers like pycnogonids (sea spiders) and xiphosurans (horseshoe crabs).
- ephemeral speciation: when new species evolve and also disappear quickly.
- karyotype: a chart that shows the size and shape of each set of chromosomes an organism has.
- PCR primer: a short bit of DNA that tells a PCR machine (a DNA copier) where to start and stop the copying process.
- peptides: the building blocks of proteins.
- species complex: a group of closely related species that may require molecular analysis to tell apart.
