Arachnews: April 6, 2020
A week’s worth of news, art, and science about amazing arachnids.
It’s been a fairly eventful week in the arachnid world, full of news both good and bad; educational podcasts, threads, and videos; and plenty of scientific research.
Terms in bold are defined in the glossary at the end.
Art & Social Media
- Roses are red,
Huntsmen are placid,
This Aussie wood scorpion
Fell prey to a sparassid. [Twitter]
Education & Outreach
- On the Human Biology Association’s podcast Sausage of Science, UNL’s Eileen Hebets talks to Cara and Chris about her scientific career, and how spider communication is surprisingly like human communication. [Sausage of Science]
- In response to a follower’s question, Alexandre Michelotto explains the various ways spiders fly—using the wind, the Earth’s electrical field, and their bodies and legs. (Portuguese) [Twitter]
- The British Arachnological Society is hoping to get people to discover the wildlife in their own houses. They have just launched their Cellar Spider Survey, asking people to send in pictures and details of cellar spiders they find in their homes. [British Arachnological Society] [Twitter]
- Related: Chris Cathrine shows how to sample and identify spiders from the yard like an arachnologist, using a bug-vac and dissecting microscope. See the description for a list of books and equipment (including the tea). He also has a second video on an essential technique: sifting through leaf litter with a garden sieve. [YouTube]
Events & News
- Tone Killick passes on terrible news about eminent arachnologist Norman Platnick, who is in hospital after suffering a fall and a stroke. [Twitter]
- Leanda Mason and Patricia Kennedy have written a tribute to the trailblazing Australian arachnologist Barbara York Main, who passed away last year. [Pacific Conservation Biology]
- Erin Powell, who did her PhD on the exaggerated, weaponized chelicerae of New Zealand opilionids, is now Dr. Erin Powell. Congratulations! [Twitter]
- A news story on the latest excavation at Germany’s famous Messel Pit, which uncovered a fantastically preserved fossil spider, Lutetiana neli. (Here’s the paper, mentioned in the Jan. 27 Arachnews.) [Der Standard]
- The Asian Society of Arachnology’s conference, which was to be held this November in Kochi, India, has been postponed for a year. It is now scheduled for November 22–25, 2021, still in Kochi. [ASA 2020]
- The organizers of the European Congress of Arachnology (August 16–21, Greifswald, Germany), say they are “monitoring the situation carefully”, and will give another update in mid-April. [ECA 2020]
- Likewise, the organizers of the Latin American Congress of Arachnology (December 13–18, Buenos Aires) are continuing to plan the conference, but will re-evaluate in mid-June. They are accepting symposium and logo proposals. [VICLA]
- If you want to study the genes controlling embryonic development in spiders, your go-to “lab rat” is the American house spider (Parasteatoda tepidariorum). There are several labs and researchers around the world doing this right now (see, e. g., this recent Dev Genes Evol issue). Here’s a very useful overview of the questions and problems they’re working on, and exactly how to study P. tepidariorum’s genes in the lab. [Paper 🔓️]
- Our blood uses hemoglobin, a protein with iron in it, to help carry oxygen around. The arthropod equivalent is hemocyanin, which uses copper. But it isn’t just for oxygen—it can also carry around other molecules, like fats and hormones. It is also involved in immune responses and healing wounds. A chapter in a recent book on body fluid proteins covers what we know about the many functions of arachnid hemocyanin. [Paper] [Sci‑Hub]
Ecology & Behaviour
- What’s eating Cuban scorpions? Other scorpions, mostly. A study of 368 instances of predation found that the vast majority—about 80%—involved scorpion cannibalism. Metal. [Paper 🔓️]
- Researchers have gotten Eremobates pallipes solifuges to mate in the lab! This is a rare sight, especially because solifuges are very difficult to keep alive in captivity. [Paper]
- Hawaii’s kīpuka are fragments of tropical forest surrounded by old lava flows — islands within islands. They are largely untouched by non-native plant species, but is it the same for arthropods? Scientists collected hundreds of spiders from kīpuka and the surrounding lava and compared the results with a similar study from 1998. While no native spiders had disappeared, non-native spiders like Cheiracanthium and Steatoda grossa have gained a foothold. [Paper 🔓️]
- There’s an ongoing debate in ecology about the factors that influence which organisms live where. To what degree does environment determine the kinds of organisms in a community? What role do randomness and geographic distribution play? Soil mites are a good kind of organism to study with regards to these questions, because there are lots of pretty similar species that all live pretty much the same way; they’re not able to travel very far; and they’re tiny, so you’re working on the scale of hundreds of metres instead of hundreds of kilometres. This study on mesostigmatid mites in Brazil’s Atlantic Forest found that different kinds of mites lived in leaf litter vs. soil, but that the kinds of mites that lived in leaf litter were better explained by environmental conditions, and the kinds that lived in soil were better explained by randomness. [Paper]
- Some oribatid mites engage in phoresy: dispersing by hitching rides on other animals, like birds. Could we get an idea of bird populations at archaeological sites by looking for the remains of mites that might have tagged along? [Paper]
Agriculture & Pest Control
- In 2000, a mysterious plant virus started spreading through Japan’s shiso-growing regions. Shiso is a leafy green herb, used as a green and a garnish in Japanese cuisine. The virus caused mottling (a. k. a. “mosaic symptoms”) on the frilly leaves, making them unfit to use; some people lost their whole crop. Over the past ten years or so, scientists have been narrowing down the cause. It’s an emaravirus*—a genus of plant viruses transmitted by Aceria and Phyllocoptes eriophyid mites. A new paper shows that perilla mosaic virus is quite different from other emaraviruses—not just genetically, as sequencing shows, but in etiology: it’s spread by Shevtchenkella mites. Controlling the mites is key to stopping perilla mosaic virus. [Paper] [Sci‑Hub]
* Named after one of the diseases they cause, European mountain ash ringspot-associated virus.
- Hey, in case anyone’s been living under a rock, humans catch a lot of diseases from bats. (Also, please go back under your rock, it’s safer there.) Is Lyme disease one of them? Probably not, at least not in Ontario. [Paper 🔓️]
- Cheletogenes ornatus is a predatory mite that shows a lot of promise as biological pest control. To find the most effective way to rear them en masse, researchers tested how the mites did with different prey: Acarus siro, a mite that infests stored foods; ye olde two-spotted spider mite Tetranychus urticae; the red palm mite Raoiella indica; and the date scale insect Parlatoria blanchardii. A. siro was the winner…or loser, depending on your perspective. [Paper 🔓️]
- In lab experiments, the predatory mite Stratiolaelaps scimitus reduced populations of parasitic root-knot nematodes (Meloidogyne incognita) living among spinach roots. The mites can successfully live and reproduce on an all-nematode diet. The next step: testing them in the field. [Paper 🔓️]
- Eutetranychus africanus, a kind of spider mite, is invasive in Taiwan, where it poses a threat to the papaya crop. A recent study shows that as temperature increases, the mites develop faster, reproduce more, and die sooner; their optimal temperature is around 27°C. [Paper]
- Related: the predatory mite Amblyseius swirskii, used to control the two-spotted spider mite Tetranychus urticae, develops faster the hotter it gets, until 37.5°C. [Paper] [Sci-Hub]
- Mildly interesting: a predatory thrips (Scolothrips longicornis) as a possible way to control the spider mite Schizotetranychus smirnovi, a pest of almond trees in Iran. Usually thrips are pests themselves. [Paper]
- In Iran, Granny Smith apple trees are particularly susceptible to the spider mite Eotetranychus frosti; Golab Kohanz trees are the most resistant. (We’ve previously seen a similar study on mite-resistant lychee varieties.) [Paper]
- Prodidominae is a group of spiders which was briefly considered its own family, but is now classified as a subfamily of the ground spiders, Gnaphosidae. A new cladistic analysis finds that some genera should be placed in a sister subfamily, Molycriinae. [Paper]
- While examining phoretic mites on beetles from the US and the Philippines, researchers realized they had found two new species of oribatid mites. Perscheloribates paracuriosus is the first phoretic oribatid found on the passalid beetle Aceraius lamellatus, and P. parakontumensis is the first found on any beetle from the Zopheridae family. [Paper 🔓️]
- A while back, these researchers concluded that the tick species Ixodes aragaoi was really I. fuscipes all along, but I. spinosus, which had previously been folded into I. fuscipes, should have stayed a separate species. Confused? Yeah, me too. Anyway, they were going through a bunch of ticks to update the classifications when they found some that didn’t fit with either species. Some belong to I. lasallei and I. bocatorensis, two species previously not recorded in Brazil; and one is a brand new species, I. catarinensis. [Paper]
- A new oribatid mite, Cerocepheus osornoensis, from the rainforest of southern Chile (specifically, Osorno Province, hence the name). The paper also includes a key to identifying mites in the family Cerocepheidae. [Paper 🔓️]
- Pholeoixodes ticks, a subgenus of Ixodes, live in their hosts’ burrows and so are rarely caught by typical tick sampling methods that involve sweeping fabric through tall grass. Researchers collected ticks from red foxes* in Slovakia to get an idea of which Pholeoixodes ticks can be found in the country. [Paper 🔓️]
* The foxes were neither cute nor alive.
- The “small, enigmatic” European harvester Dicranopalpus brevipes, originally from Sicily, Italy, is found in Sardinia for the first time. [Paper]
- Embrik Strand strikes again! Two species he named, currently in a Berlin museum, are reclassified: a sac spider from Rwanda is moved to Cheiracanthium, and a Madagascar spider originally classified as a corinnid is actually a liocranid. [Paper]
- The latest part in František Kovařík et al.’s “Scorpions of the Horn of Africa” series covers Buthus scorpions from Ethiopia and Somaliland, including two new species (B. pococki and B. somalilandus). [Paper 🔓️]
- A survey of guardstone spiders (family Phrurolithidae) across Azerbaijan, Iran, and Tajikistan turns up a new Phrurolithus species, P. azarkinae (named after arachnologist Galina Azarkina). Three more new species belong to a whole new genus, Bosselaerius. [Paper] [Sci‑Hub]
- “The cunaxid mites of the Asian part of Russia remain completely unexplored,” writes Alexander A. Khaustov in this new paper on cunaxids from Western Siberia. He has found a new species, Parabonzia sibiriensis. [Paper] [Sci‑Hub]
- Two new buthid scorpions, Isometrus tamhini and I. amboli, from Maharashtra, India, in the Western Ghats. Isometrus species are hard to tell apart from physical attributes alone, so the authors also used genetic sequencing to show that the species were different. [Paper 🔓️]
- Two new eriophyid mites, Cymedia indica and Neoacaphyllisa alangia, found on the undersides of leaves in West Bengal and Assam, India.[Paper] [Sci‑Hub]
- A new species of eriophyid mite, Phyllocoptes maackis, has been found on spindle-trees (Euonymus maackii) in Jilin, China. They don’t seem to hurt the tree, so they’ve got that going for them. [Paper 🔓️]
- cladistics: a method of constructing evolutionary “family trees”, based on figuring out which traits came from a common ancestor and which ones evolved later. (Here’s more explanation.)
- hemocyanin: the copper-containing protein used to carry oxygen around (among other things) in many arthropods’ and molluscs’ “blood”.
- phoresy: when an organism travels by hitching a ride on another one. Phoretic mites and pseudoscorpions are very common.
- solifuge (also solifugid, solpugid): an arachnid in the order Solifugae. These bizarre-looking but harmless desert dwellers are commonly known as camel spiders, sun spiders, wind scorpions, etc.