Arachnews: April 13, 2020

Your week in arachnid art, photography, news, and science.

This week: strange and wonderful photos; one of the 20th century’s greatest arachnologists passes away; ECA 2020 postponed; and a small but mite-y assortment of new research.

Art & Social Media

A Holconia huntsman covered in mites and pseudoscorpions. “I didn’t notice the pseudoscorpions until I processed the photo. Never stop looking closer!’ • Caitlin Henderson

The peacock jumping spider Maratus volans with prey • Michael Doe

Soft ticks (family Argasidae)! These ticks were collected from domestic chickens. • Matt Bertone

This striking tetragnathid was photographed by Thomas Shahan several years ago in Puerto Rico • Thomas Shahan

• iNaturalist’s Observation of the Day for April 9 is this long-jawed orbweaver (Alcimosphenus licinus), photographed by Thomas Shahan back in 2015 (but only uploaded to iNat now). [Twitter]

An Argiope appensa orbweaver feeding on a blue-tailed skink in Guam • Tony Azios

• Roses are red,
  Skinks’ tails are blue,
  This Argiope appensa
  thinks they’re tasty, too. [Twitter]

• Zoos are posting cute videos of animals exploring the suddenly human-free exhibits. The Queensland Museum joins in the fun with this spectacular peacock jumping spider puppet. [Twitter]

• The Danish tennis star Caroline Wozniacki was alarmed to find three spiders in her pool in Missouri, “alive walking around under water”. Probably Dolomedes fishing spiders, which are known to do this, but it’s hard to tell from the photo. [Twitter]

Education & Outreach

• Ah, springtime in Canada. The very first “watch out for ticks” news articles are beginning to appear here and there. This article reminds people of basic safety precautions to take when outdoors, as well as how not to remove ticks. [Swift Current Online]

• Black widow researcher Laura Gatch reads Bethany Barton’s I’m Trying To Love Spiders on video “for a teacher friend”. [YouTube]

• A reminder that the British Arachnological Society is putting out the call for people stuck at home to send in observations of their household cellar spiders! Everything is explained in this video; there’s also this PDF, and you can tweet at @BASSurveys for help. [YouTube]

Events & News

• The preeminent arachnologist Norman Platnick has passed away after (as we reported last week) suffering a fall at home. Over his long career (starting with getting his bachelor’s in science at the age of 16!) he described thousands of species, founded the indispensable World Spider Catalog, and transformed the way we classify spiders. His hundreds of publications span almost 50 years, including a forthcoming book. His son Will Platnick is starting a fund to carry on his work in spider taxonomy. His colleagues have prepared a wonderful obituary; this 2005 NYT article also provides a vivid glimpse into Platnick’s life and impact on the field.

[The] conceptual cobwebs in the attic of systematics had grown rather dense by the late 1970s, and it was high time to give the field a thorough cleaning. He was one of the more prominent members of a group stripping the attic to its bare wood…

His theoretical inclinations may have been seen as a denial of advances in molecular and statistical methods, and to a certain extent they were, but it is more productive to see them for something else they also were: an affirmation of the value of the simple, permanent, and central discovery of what is: the organisms of this earth and their visible traits.

• Wayne Maddison reflects on Platnick’s work and legacy in spider systematics. [Reflections on a Spider’s Eyes]
• The European Congress of Arachnology, originally planned for this summer in Greifswald, Germany, has been pushed back a year. The new date is August 22–27, 2021. More details can be found on the conference website. [ECA 2020]

Research

New articles in Experimental and Applied Acarology and Systematic and Applied Acarology mean this week is basically all mites.

• Science soldiers on, cataloguing the acaricidal potential of every essential oil in existence. (I’m still not sure to what degree this is a sophisticated multi-level marketing scheme run by scientific journal publishers.) This week, it’s lemongrass oil vs. the longhorned tick (Haemaphysalis longicornis). Results are promising. [Paper] [Sci‑Hub]
• The red palm mite (Raoiella indica) is spreading throughout Brazil. How vulnerable are Brazil’s native palms? A study compared how red palm mites fared on their favourite tree, the coconut palm, versus five palm species native to northeast Brazil. Luckily, the mites don’t do as well on the Brazilian species, except for the carnauba palm (Copernicia prunifera). (Previously: red palm mites spotted on ornamental palms imported to Paraguay from Brazil.) [Paper] [Sci‑Hub]
• Tiny Pyemotes mites can cause galls on trees, infest grain, and so forth; many are known as “itch mites” because it itches when they bite you. It’s not all bad, though: Pyemotes zhonghuajia might help kill fall armyworms (Spodoptera frugiperda), a serious agricultural pest recently detected in China. [Paper]
• Right now, scientists studying the honeybee mite Varroa destructor have to collect the mites from infested honeybee colonies, which is not only a pain in the ass, but very dangerous for the bees. A group of researchers at the University of Florida are working on a way to raise V. destructor mites in the lab. They report the results of four different methods in a new paper. [Paper] [Sci‑Hub]

The spread of tracheal mites through Japanese honeybee colonies, expanded with new data from Maeda & Sakamoto 2020.

• Over the past 10 years, the tracheal mite Acarapis woodi, which infests Japanese honeybee (Apis cerana japonica) colonies, has spread across Japan. The mites cause many more bees to die over the winter. This interesting paper discusses how hobby beekeepers can detect the mites, how traditional beekeeping methods have kept mites at bay in some areas, and what can stop the spread of mites going forward. [Paper] [Sci‑Hub]
• There’s a bunch of different ticks that can transmit Rickettsia bacteria, which cause Rocky Mountain spotted fever and similar diseases. Researchers in the northern Mexican state of Tamaulipas, just over the border from Texas, collected ticks from humans and animals (mostly dogs) and tested them to find out which species were carrying Rickettsia. They found that the widespread brown dog tick (Rhipicephalus sanguineus) is the most likely vector for tick-borne rickettsial disease in the state. [Paper] [Sci‑Hub]
• What disease-causing bacteria are in the ticks of Greenbelt National Park, MD? Basically just our old pal Borrelia burgdorferi, which causes Lyme disease. At the moment this is kind of moot, because the park is closed to prevent the spread of a much more dangerous disease: COVID-19. [Paper]
• Related: Amblyomma ticks collected from wild birds in Panama mostly carry the potentially disease-causing bacteria Rickettsia amblyommatis. No signs of other bacteria like Borrelia, Bartonella, Babesia, etc. [Paper]
• Okay, I just want to say that I love the word ecdysteroid. It’s a steroid that regulates arthropod molting (ecdysis)—get it? Ecdysteroid molecules are kind of like keys. The “locks” are nuclear receptors, molecules that also act as transcription factors. So they basically “unlock” genes related to molting. Anyway, these researchers sequenced the gene for a nuclear receptor in the red citrus mite (Panonychus citri). It is mostly active when mite nymphs start their last molt before adulthood. Turning the gene “off” before that point results in underdeveloped mites that mostly die. So they figure it probably has something to do with molting! This is basically like in insects, but you have to check, because you never know. [Paper]

A scorpion glowing under UV light in California’s Mojave Desert • Jerry Kirkhart

• What makes scorpions glow under UV light? We’re still not 100% sure! Researchers in Japan and Egypt have isolated a new fluorescent compound from the exoskeleton of Liocheles australasiae, a scorpion found across Asia and Oceania. But what’s it for? It might protect scorpions from antifungal infections; it doesn’t seem to act as a sunblock, which is another hypothesized function of scorpion fluorescence. [Paper] [Sci‑Hub]
• Hey, you know how we constantly talk about the possible medical applications of arachnid venom? Well, here’s an example: a peptide from scorpion venom reduces some motor skill learning impairments IN MICE affected by prenatal alcohol exposure, which is kind of like FASD in humans. [Paper] [Sci‑Hub]

Taxonomy

Americas

• “Fifty-five pats of cattle manure….moist inside and dry on the top surface…” Researchers in Brazil sequenced DNA from macrochelid mites found in cowpats to complement traditional identification methods. Become an acarologist, they said. See the world, they said. [Paper] [Sci‑Hub]
• A new mite, Eutrombidium carajas, found parasitizing Phalangopsis crickets in Brazil. [Paper]
• How diverse are populations of cattle ticks (Rhipicephalus microplus) in northwestern Colombia? Not very. [Paper] [Sci‑Hub]

Europe

• No one knew exactly what the larvae of the water mite Hygrobates prosiliens looked like…until now, in this paper on specimens from Russia. [Paper] [Sci-Hub]

Africa

• Several laelapid soil mites are recorded in Egypt’s Assiut Governorate for the first time. [Paper]
• A new species of mite, Leptus cameroonicus, found parasitizing lamenting grasshoppers (Eyprepocnemis plorans) in Cameroon. It’s a first for the grasshoppers too, as this is the first time anyone has found Leptus mites on this species. [Paper]

Asia

• Two new Wanniyala cellar spiders from Sri Lanka. [Paper] [Sci‑Hub]
• Two new ptyctimous steganacarid mites, Plonaphacarus chuxiongensis and Hoplophthiracarus jianchuanensis, from Yunnan, China. [Paper]
• Two new Trachygamasus parasitid mites from China. [Paper]
• Two new Pholcus cellar spiders, P. jingnan and P. longlin, from Guizhou and Guangxi, China. [Paper] [Sci‑Hub]
• A checklist of the ticks found on the island of Pulau Tioman, Malaysia. The island doesn’t have many kinds of terrestrial vertebrates, which means there aren’t as many kinds of ticks. There are a few “specialist” ticks, though, like Haemaphysalis traguli, which feeds on the greater mouse deer, and H. atheruri, which feeds on porcupines. [Paper] [Sci‑Hub]

As always, thank you very much for reading! Many thanks to Sebastian Alejandro Echeverri for looking this over. Suggestions, corrections, and other feedback is most welcome. Just drop us a (silk) line at @arachnofiles. 🕷️

Glossary

• acaricide: a pesticide against mites and/or ticks.
• ecdysteroid: a hormone that kick-starts the molting process in arthropods by activating a nuclear receptor.
• nuclear receptor: a transcription factor that, when activated by a matching steroid hormone, can regulate the expression of certain genes (that is, turn them on/off/up/down). You may be wondering if that’s how it works in humans, too, and the answer is hell yes.
• peptide: a molecule made of a bunch of amino acids strung together. A bunch of peptides strung together is a protein.
• ptyctimous: capable of ptychoidy, the ability to fold up into an armoured ball or box like a little mite Transformer. More on ptyctimous mites here.
• systematics: the study of how different groups of organisms are related, which reflects how they should be classified. Our Taxonomy section, which also includes faunistic data and phylogenies, should arguably be called Systematics. Cladistics, phylogenetics, systematics, and taxonomy are closely related, often overlapping concepts. Understanding the differences between them kind of makes us want to cry, so instead here are some resources: Wikipedia, the UC Museum of Paleontology, Mike Taylor.
• transcription factor: a type of protein that gloms onto DNA and affects how often genes are expressed. Because there are so many different kinds of transcription factors, their effects can be varied: some turn genes on and off; others only do so in specific parts of the body or at specific times in development. Changes in how genes are expressed, as done by transcription factors and other systems, are a big reason that we can share most of our DNA with other animals and yet look so different.