Arachnews: March 23, 2020
Your weekly roundup of arachnid art, news, and science.
In this week’s edition: conferences postponed, 3D jumping spiders, 20 years’ worth of scorpions, spiders with noses and harvestpeople with horns, lots of research about repelling ticks, and more.
Terms in bold are defined in the glossary at the end of the post.
Art & Media
Education & Outreach
- DigitalLife3D, in collaboration with the Morehouse Lab, has released their (CC-licensed) 3D models of the fiery-haired paradise jumping spider (Habronattus pyrrithrix)! There’s a courtship pose and a sitting pose. You can use the model in engines like Unity and Unreal. [Sketchfab]
- Kelly Brenner has put together an easy-to-follow guide to finding your own face mites, including three leading methods: tape, nail polish, and super glue. Do try this at home, kids! [Kelly Brenner]
- “Steve Buchanan’s illustrations are top notch and I love that some of them have shadows, giving the impression that they are standing on the page. In most cases, both males and females are shown and any reservations I may have had with a guide such as this quickly went away after going through the illustrations.” Dave the Bug Guy reviews Richard Bradley’s Common Spiders of North America. [Dave the Bug Guy]
Events & News
𝔶𝔢 𝔬𝔩𝔡𝔢 𝔭𝔩𝔞𝔤𝔲𝔢
- The ninth Symposium of the European Association of Acarologists, EurAAc, is scheduled for July 13–17 in Bari, Italy. Due to travel restrictions in the wake of COVID-19, the deadlines for early bird registration & abstract submissions have been postponed till April 30. Keep an eye on the site for more announcements. [EurAAc]
- The International Society for Behavioural Ecology conference planned for this year has been pushed back two years. It will now be held September 11–16, 2022 in Melbourne, Australia. [Twitter]
- The schedule for the yearly American Arachnological Society meeting has been pushed back: this year’s (now cancelled) meeting at University of California Davis has been transferred to 2021, and the 2022 meeting will be at the University of Akron. In the meantime, society president Dr. Greta Binford requests “that we add some buoyancy to the situation by sharing photos of inspiring arachnids, interesting anecdotes, stories about field work, comics, songs, videos, lists of the spiders we see in our backyards, recent publications…to our AAS social media feeds including Facebook (American Arachnological Society), Instagram (#americanarachnologicalsociety), Twitter (#AmericanArachnologicalSociety) and others.” We’re on it, Dr. Binford.
- Behavioural ecologist Niels Dingemanse sets the record straight on questions raised by the recent Science piece and Leonid Schneider’s blog post. Journal editors and co-authors have not been silenced by lawyers’ letters, he says; they have been quiet on social media and in the press to avoid misunderstandings. “Many interviewed before were not interested in reporting to Science Magazine. Science just retracted a quote of Pruitt due to a ‘misunderstanding’…exactly what we wanted to avoid.” [Twitter]
Parasitism & Predation
- That amazing footage of Ariamnes sneaking up on prey is from research written up in the latest journal of the Tokyo Spider Study Group. Several species of cobweb spiders (family Theridiidae) are known for hunting other spiders. Each species has a unique way of using their hind legs to throw silk over their prey. (In Japanese.) [Paper 🔓️]
- Here’s a rare case of two ant spiders (family Zodariidae) parasitized by flies! The parasitized spiders didn’t eat, and constructed little silk-and-sand moulting retreats for themselves within a day. One of the flies made it to hatching. You can read more about the process in the full paper, which is open access. [Paper 🔓️]
- Phytoseiid mites can help spread entomopathogenic (bug-killing) fungal infections to the two-spotted spider mites (Tetranychus urticae) they prey on. This has interesting implications for agricultural pest control. [Paper] [Sci‑Hub]
- A little detail I liked in this study from India: testing a plant-based acaricide for the tea red spider mite involved sending the tea leaves to professional tea tasters to make sure it didn’t affect the taste of the final product. [Paper 🔓️]
P. S. I went down a 19th-century acarology rabbit hole trying to figure out why the tea red spider mite is called Oligonychus coffeae. Does it plague coffee, too? They’re quite different plants. Or is it named after some guy called Coffe? Don’t laugh, it happened with Sickius.
Ticks and Tick-borne Disease
- Piling up leaves where lawn meets forest creates a fantastic environment for black-legged ticks (Ixodes scapularis). To reduce ticks on a property, the authors suggest removing the leaves entirely or mulching the leaves. (Or, perhaps, get rid of your lawn?) See the Entomology Today story. [Paper 🔓️]
- In lab experiments, clothing treated with the pesticide permethrin repels nymphs of the Asian longhorned tick Haemaphysalis longicornis, a recent arrival in the United States. [Paper 🔓️]
- Researchers measure pesticide resistance by seeing what concentration of the chemical kills only 50% of the target pests. For lone star ticks (Amblyomma americanum) and the acaricide fipronil, used in tick products for pets, that threshold is very low (0.0208%). In other words, you need to really water that stuff down to leave half of the ticks alive. This means fipronil is really powerful against lone star ticks. [Paper]
- Related: in some parts of India, cattle ticks are becoming resistant to fipronil. 😬 [Paper] [Sci‑Hub]
- Related: are some cattle breeds less susceptible to being fed on by ticks? If it has a genetic basis, that opens up a lot of interesting possibilities. [Paper] [Sci‑Hub]
- Dermacentor silvarum are home to a rich variety of bacteria, particularly in their saliva, but also throughout the rest of their digestive system. This study compared the microbiomes of partially and fully fed ticks found on sheep in northern China. [Paper] [Sci‑Hub]
- Ticks have very interesting metabolisms. They spend a lot of their life not eating, waiting for a host to come by. Some can survive months without food! One way scientists study insect metabolism is with a type of spectrophotometry. After mashing up a bunch of bugs and adding chemicals that cause colourful reactions with protein, fat, carbohydrates, etc, the colour can be measured very precisely with a device called a spectrophotometer. This tells you how much protein, etc., is in the mixture. Two researchers wanted to see if this technique would also work with ticks. [Paper 🔓️]
- Okay, so if you’re like me and are running on half-remembered high school biology lessons and pop science, you may have heard of “junk DNA”—stretches of DNA that don’t code for any proteins. A lot of that DNA still gets transcribed into RNA. That RNA doesn’t make any proteins, but that doesn’t mean it doesn’t do anything. It still affects how genes are expressed (which is why scientists don’t really talk about “junk DNA” anymore). Anyway, this study looked for a particular sort of this RNA—long sequences found in between genes, a. k. a. lincRNA—in the transcriptome of house dust mites (Dermatophagoides farinae). The authors think house dust mites’ lincRNA might affect the production of the proteins people are allergic to. [Paper 🔓️]
- Tyrophagus putrescentiae is a fungus-eating mite commonly found in stored food products. An earlier study found that its mitochondria were missing three of the genes that code for tRNA (transfer RNA, molecules needed to build proteins), which is weird because those genes are really important. This group of researchers sequenced T. putrescentiae’s mitochondrial DNA from scratch, this time using mites from several different populations. A careful search turned up the “missing” genes. [Paper] [Sci‑Hub]
- Happy 20th birthday to scorpion journal Euscorpius! For their anniversary issue, they’ve put together a paper cataloguing the hundreds of new species and dozens of genera first described in the publication. There are also excellent photos. [Paper 🔓️]
- Three new Arnoliseus amycine jumping spiders from Brazil. Check out the weird little horns on the males’ chelicerae! [Paper 🔓️]
- Brazil’s little-known “Pinocchio cobweb spider” (Craspedisia cornuta) has a nose. And now there are high-quality scanning electron microscope photos of it. [Paper] [Sci‑Hub]
- The red palm mite (Raoiella indica) has been steadily spreading through South America since 2008. Now it’s been spotted in Paraguay on ornamental palms imported from Brazil. [Paper] [Sci‑Hub]
- Until now, we had only found larvae of the soft tick Ornithodoros peruvianus, a bat parasite in Peru. A new paper adds descriptions of their nymph and adult stages, and notes that contrary to previous findings, nymphs were able to moult to the adult stage without feeding. This might be a characteristic common to bat ticks. [Paper] [Sci‑Hub]
- This dataset of over 15,000 spiders collected in Argentina’s Atlantic Forest includes not only what species or genus they were, but a ton of other information: body size, leg length, whether they were active during the night or the day, and so on. [Paper 🔓️]
- I’m screaming because this paper, ostensibly the first part of a revision of the western Cuban scorpion genus Tityopsis, is basically an extended dunk on the work of another Cuban arachnologist. They don’t have a single good word to say about Luis F. de Armas, man. Anyway, it’s also an enlightening look at the hard work it takes to find scorpions. Two juvenile T. pumila in captivity were wiped out by parasitic flies. The elusive T. canizaresorum was only found because it got into a collector’s hotel bed and stung him in the back, “[causing] him excruciating pain for about two hours”. The authors tried to raise some in captivity to see if they were indeed parthenogenetic, but a citywide anti-dengue spraying killed them all. And so on. [Paper 🔓️]
- Related: the much-maligned Luis de Armas reports that the central Cuban scorpion Didymocentrus sanfelipensis was found further east than before, in a marshy area much different from its typical dry scrubland habitat.[Paper 🔓️]
- Unlike the vast majority of new species, this newly described scorpion, Vaejovis elii, got media coverage—in this 2016 news segment (starting at 2:53). As far as we know, it only lives on Mingus Mountain in Arizona. [Paper 🔓️]
- So in scorpion mating, the male, uh, sort of squeezes a special structure called a spermatophore out of his genital opening. (The bottom end is sticky, so it is fixed to the ground.) Then he guides the female over it so it goes into her genital opening. In scorpions, spermatophores are made of two identical halves called hemispermatophores. They also carry a mating plug used to keep sperm in the female’s genital tract (and other males’ sperm out). In recent years, scientists have realized scorpions’ spermatophores and mating plugs are quite unique and can be used to identify individual species and how closely they’re related to each other. The Official Specimen* of the species Vaejovis lapidicola didn’t come with a spermatophore. So these authors tracked down the quarry where it was collected in 1938 so they could collect a historically accurate one. [Paper 🔓️]
* In this case, the species was first described based on a group of specimens. But in 2006, when they updated the description, they picked one of those specimens to be the Official Specimen. There are specific terms for each of these things, but I am choosing to spare you the jargon.
- A survey of some 900 ground spiders collected in a military park in South Carolina, US found 85 species from 22 families and compares species richness across different types of habitats. [Paper]
- This inventory of spiders from around the Lammi Biological Station in southern Finland, collected by university students, is part of a project to assess biodiversity around the world with a standardized sampling protocol. [Paper 🔓️]
- This paper officially brings the number of phytoseiid mite species found in Slovenia to 22. [Paper 🔓️]
- Oh hey, this is the first record of an amblypygid in Jordan, ever! It was on someone’s bathroom wall. [Paper 🔓️]
- A bunch of Bryobia clover mites found in Latakia City, Latakia, Syria. One, B. syriensis, is new to science. Others are, like, weird mutant mites. [Paper 🔓️]
- Aceria eriophyid mites are agricultural pests on many kinds of plants (previously in these pages we’ve seen them on lychees, coconuts, and grass). This paper includes a list of Aceria mites found around the world on Solanaceae, or nightshades, the family that includes tomatoes, potatoes, peppers, and more. It also introduces a new species, A. ajabshiriensis, found on boxthorn (another nightshade) in Iran. [Paper 🔓️]
- Beierochelifer peloponnesiacus, found in the province of East Azerbaijan, is the first Beierochelifer scorpion found in Iran so far. [Paper 🔓️]
- Nine new species of Scorpiops scorpions from across Pakistan, India, Nepal, and China. Also, a specimen previously classified as a subspecies of S. petersii has been given its own species, S. vonwicki. You might think it was collected by its namesake, a Russian zoologist named Von Wick. But the authors figure it was found by a British officer, Noel Williamson, who was killed in 1911 by Adi, people from Himalayan hill-tribes who the British had previously tried and failed to conquer. In retaliation the British launched a “punitive expedition” against the hill-tribes. There was also a scientific element to the expedition, a dark reminder of how Western science and colonial violence have long been inseparable. [Paper 🔓️]
- The female of the sac spider Pristidia cervicornuta has been found for the first time, in the mountains of Hainan Island, China. [Paper 🔓️]
- The phytoseiid mite Amblyseius obtuserellus has been found for the first time in Vietnam, in a Mekong Delta citrus orchard. These predatory mites are much sought after in agriculture. [Paper 🔓️]
- Three new species of epedanid harvestpeople from Thailand. Species in this family are known for having a “surprisingly long pointed spine” on their eye-turrets. They’re magical unicorns! ✨ [Paper 🔓️]
As always, thank you for reading! Many thanks to Sebastian Alejandro Echeverri for edits. Corrections and suggestions are most welcome. Just drop us a (silk) line at @arachnofiles. 🕷️
- acaricide: a pesticide that kills mites or ticks.
- entomopathogenic: causing disease in insects (or other terrestrial arthropods).
- lincRNA: long non-coding intergenic RNA. Okay, so genes are stretches of DNA that get transcribed into RNA that gets translated into proteins, which make up like everything in your body, right? In between genes there’s a lot of DNA that doesn’t code for any proteins, but it still gets transcribed into long stretches of RNA. That’s lincRNA. It seems to affect how genes get turned into proteins.
- mating plug: a hardening glob of stuff that plugs up the female’s genital tract, serving to both keep her mate’s sperm in and keep other males’ sperm out. Mating plugs are found widely across the animal kingdom, from arthropods to mammals.
- microbiome: the community of all the bacteria and other microscopic organisms living inside an animal.
- parthenogenetic: able to reproduce without mating.
- spectrophotometry: a process that precisely measures the colors of light (“spectra”) reflected (or transmitted) by an object. In biochemistry, this is sometimes used to figure out what molecules/elements something is made out of. Different substances reflect light in their own particular way. So if you know what colours of light come off of the various things that might be in your sample, you can measure it with a spectrophotometer, and deduce which substances are actually in there.
- spermatophore: a “sperm-carrying” (that’s literally what it means) structure produced by some male organisms in order to inseminate females. It is fixed to the ground or a leaf or whatever, and then the female plops herself on top of it. In scorpions, the spermatophore consists of two identical halves, hemispermatophores. (Hemi = “half”, like your brain’s hemispheres.)
- transcriptome: all the RNA a cell (or a bunch of cells) produces. Cells all have a full copy of an organism’s DNA, but they only transcribe and translate some of it, depending on what the cell does. Looking at the DNA will tell you what genes an organism has, but you need to look at the RNA to see what genes are actually getting used at that particular time or by those particular cells. I think of the transcriptome as “the receipts”.
- tRNA: transfer RNA. Okay, so genes are stretches of DNA that get transcribed into (messenger) RNA that gets translated into proteins. tRNA is used to build those proteins from messenger RNA. Every piece of tRNA has a bit that matches a complementary sequence on the messenger RNA. And on the opposite side of the molecule, the tRNA carries an amino acid, the building block of protein. There are many different kinds of tRNA, each matching a different mRNA sequence, and each holding a different amino acid. As the tRNA matches with its complement on the messenger RNA, the amino acid it was carrying gets attached to the growing protein.