#Arachtober 2: anystid renaissance! Commonly called whirligig mites for their constant frantic and erratic running, these large (~1 mm*) predatory mites in the family Anystidae have a population boom in early to mid-June and seem to increase in numbers again in autumn, at least around here. They eat aphids, small midges, each other, etc. This one seems to be eating some kind of barklouse (Psocodea)?

* Given that many mites are microscopic, any mite one can clearly see with the naked eye counts as "large".

#ArthroBeauty #LichenSubscribe #arachnids #mites #Acari #Acariformes #Prostigmata #Anystidae

#Arachtober 3: meet a representative of another order of arachnids, Opiliones (a.k.a. harvesters, harvestmen, daddy-long-legs [though this can also refer to a kind of spider, crane flies, and even a plant]). They have some key differences from spiders: head and abdomen segments fused together; no silk or venom (i.e. they are entirely harmless); only two eyes; and instead of using pedipalps to transfer sperm during mating, they have an intromittent (insertable) organ, a penis or aedeagus.

I think this is the common species _Phalangium opilio_, introduced from Europe. There are several thousand different species in this order!

#ArthroBeauty #arachnids #Opiliones #Phalangiidae

#Arachtober 4: March mating mesostig madness!

These are an ubiquitous sort of soil-dwelling predatory mites, likely in the family Parasitidae (ironically, primarily predators) in the order Mesostigmata in the superorder Parasitiformes. They are only very distantly related to the whirligig mite I posted the other day, which is in superorder Acariformes. While the two superorders are traditionally grouped together under Acari, it is likely they don't share a common ancestor and should be treated separately. So I'm counting them as a different group!

#iNaturalist observation: https://www.inaturalist.org/observations/275521159  

Some pro-level photos and info about mesostigs: https://www.chaosofdelight.org/all-about-mites-mesostigmata

#ArthroBeauty #arachnids #mites #MiteSex #taxonomy #Acari #Parasitiformes #Mesostigmata #Parasitidae

#Arachtober 5: the last order of arachnids I have found, pseudoscorpions! They look kind of like scorpions without tails; they are found basically everywhere on earth but Antarctica, but they are absolutely tiny and live in places like under tree bark, under rocks and logs, in leaf litter, etc., so you will rarely see them unless you're looking for them. Sometimes they can be found clinging to the legs of larger flying insects with their little claws, or indoors eating booklice and other tiny household insects.

The ones in my garden are so small you might take them for mesostigmatid mites at first glance. This one has captured a soil-dwelling mite of some kind.

#iNaturalist observation: https://www.inaturalist.org/observations/99203146  

#ArthroBeauty #arachnids #pseudoscorpions #Pseudoscorpiones #Cthoniidae

#Arachtober #MiteMonday: just a good old red velvet mite (_Allothrombium_).

Just imagine having a guinea pig-sized one, as a pet. It would be soft and squishy. It would enjoy squeezing into little crevices to nap. You could brush it, very gently. It wouldn't see very well. It could climb up things with little retractable claws. You could probably feed it mealworms.

#ArthroBeauty #arachnids #mites #Acari #Acariformes #Prostigmata #Parasitengona #Trombidiidae

#Arachtober 7: can't go wrong with a classic, the photogenic bold jumping spider (_Phidippus audax_). In my experience they are shy at first, but if you take a little extra time and are patient, they become curious and friendly.

#ArthroBeauty #JumpingSpiders #spiders #Araneae #Salticidae

#Arachtober 8: these small, delicate dish-shaped webs are made by mesh-web weavers, family Linyphiidae. Look for a small smooth spider with thin tapered legs hanging upside down, waiting to size any small insects that fall onto the web.

#ArthroBeauty #spiderwebs #spiders #Araneae #Linyphiidae

#Arachtober 9: a very cool orbweaver, _Gea heptagon_! Named because of its seven-pointed abdomen. So far I have only found them low among the grass in a particular marshy meadow. The juveniles have similar circular web decorations as young _Argiope_.

#ArthroBeauty #spiders #Araneae #Araneidae

#Arachtober 10: happy #InternationalJumpingSpiderDay! Here is one of my favourite species, the peppered jumper _Pelegrina galathea_, seen recently. I find the females' patterns so mesmerizing. This one is brown but they can also be just black and white.

While I've found them in all manner of places, I've found that tansy flower heads are a good place to look for them. They like to make little silk retreats under the dense canopy of flowers.

#ArthroBeauty #JumpingSpiders #spiders #Araneae #Salticidae

#Arachtober 11: a little thin-legged wolf spider (_Pardosa_) on a blade of grass in a marshy meadow. They can be practically as jumpy as jumping spiders and are very hard to get close enough to to photograph.

#ArthroBeauty #WolfSpiders #spiders #Araneae #Lycosidae

#Arachtober 12: a small yellow sac spider (_Cheiracanthium_) perches on a fence post and releases a stream of silk strands that are separated and carried aloft by the breeze and (as we've learned in recent years) atmospheric static electricity. If the silk catches on something, the spider can use it to bridge a long gap. Smaller spiders can be borne aloft entirely and traverse long distances, a behaviour called ballooning.

#ArthroBeauty #SpiderSilk #SpiderBehaviour #spiders #Araneae #Cheiracanthiidae