Tag Archives: Arachnids

June Morphology Fail

28 Jun

Here’s another Taxonomy Morphology Fail for your edification and/or entertainment.  See if you can spot this one.

I present:

Pedipalps are not, as it would happen, gonads.  In male spiders these modified mouthparts* are sometimes called “boxing gloves.”  While they are used to transfer sperm from the male spider’s reproductive organs to the female’s, they are not in any way involved with sperm production.

I would expand upon the boxing glove sperm delivery analogy but it gets unsettlingly pornographic very quickly.

via Discovery News

*To be more accurate pedipalps are probably homologous to crustaceans’ second pair of antennae.

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Pseudoscorpions

31 May
Pseudoscorpion.

Pseudoscorpion.

Here’s a tiny little predator I picked out of a leaf litter sample.  Pseudoscorpions are another cool bug that I had no idea existed until I started studying entomology.  These charming little arachnids are named for their resemblance to tiny, stingless scorpions.  At only a few millimeters in size, they prey on other small organisms such as insect larvae, mites, ants, and lice.  Although fairly common and widespread, they often go unnoticed.  (When found they are sometimes mistaken for ticks or small spiders.)

A tiny pseudoscorpion perched on a finger.

A tiny pseudoscorpion checks its claws.

Like scorpions, the front ‘claws’ of the pseudoscorpion are derived from the pedipalps (a type of mouthpart). Although they lack a stinger, most pseudoscorpions have a venom gland and duct in their pincers instead, which they use to immobilize their prey.  (Their claws are too small to enable them to sting humans.)  They then digest their prey externally by pouring digestive fluids over their captive in a method similar to spiders.  Like spiders, pseudoscorpions have spinnerets and can spin silk to construct shelters.

Pseudoscorpion perched on a finger.

Pseudoscorpion perched on a finger.

Sources and additional reading:

Q&A

3 May

Today I am answering RANDOM QUESTIONS FOUND IN MY BLOG SEARCH HISTORY.  Just for fun.

Let’s get started.

do insects have legs on their abdomen

Nope.  They have legs on their thorax.

what does dead lice look like

Pretty much like live lice.

do ants sting or pinch

Both, depending!

spider has how many legs

Eight.

Large wolf spider on face (8legs2many)

how ants carry food

In their jaws or as liquid food stored in their crop.

is ladybug one word

Yep.

did you mean: black hairy spider with white face

…no?

what adaptations do fire ants have

Lots! One cool example is they can form living rafts of ants to survive floods.

do katydid nymphs sting?

Nope.

carpet beetles bite

Not people.  They will wreck natural fibers and insect collections, though.

do carpenter ants live alone or with family?

With family.

Dimorphic carpenter ant workers at a nest entrance.

a bug with six legs and looks like a lady bug

Sounds like a ladybug.  😀

…or it could be a mimic, taking advantage of the ladybug’s warning coloration.  There are a number of beetles (and even spiders) that do this.

small bugs in bathroom
insects that live around the toilet
bug that eat toilet paper
silver bugs in bathroom
bathroom bugs tiny
little silver bugs in my bathroom
little bugs in bathroom
silver insect, bathroom
tiny little bugs in the bathroom
bugs in bathroom

Could be silverfish.  Or…baby roaches?

silverfish with legs

Mostly a thing that is true, yes.

i found a weird insect in my bathroom how do i recogbize it

Try posting a picture to BugGuide’s awesome ID Request section.  Or describing some recognizable features.

wasp or beetle?

I like beetles, personally.

different types of insects and their names with pictures

This is an excellent description of my blog!

6 legged reptile

That is definitely 2manylegs.

ant – mini spider queen

What.

show me a picture of a fuzzy worm

Okay.

A tiger moth caterpillar (Arctiidae) climbs a grass stem.

That’s actually a caterpillar, though.

small bug 6 legs

Wow, that’s kind of…all of them.  Here’s a cool one.

small jumping bugs

That could be a planthopper!  Or a flea.  Or a springtail.  Or…a baby grasshopper.  Or something else.

fire ants go to war with jumping spiders

That sounds awesome. O_O

Black on Black

8 Mar
Face view of camouflaged daddy-longlegs spider.

A cryptic black harvestman blending in to the scorched bark of a tree in a post-wildfire zone in the Chiricahua Mountains in Arizona.

One interesting ecological factor to explore in the Chiricahua Mountains in Arizona is the vast areas that have been swept by wildfires in the past few years.  For example, the Horseshoe 2 wildfire in 2011 was the fifth largest wildfire in Arizona history, affecting more than 220,000 acres.  When I visited the mountains, acres of still-scorched trees surrounded by wildflowers and new growth sat side by side with untouched forest and thick underbrush making for an interesting environmental mosaic.  In some of the burned habitat I spotted the above harvestman blending in perfectly with the scorched bark–perhaps a something of a lucky break for this species?

Black daddy-longlegs spider on burned tree.

Camouflaged black harvestemen on burned tree.

Havestmen, more commonly called daddy longlegs, are a type of arachnid in the order Opiliones.  Although they are often mistaken for spiders harvestmen have very different biology and morphology, with a single pair of eyes, a wide connection between head and body, and no venom glands!  In addition, many opilionids are omnivores and scavengers, eating all manner of small insects, fungi, plant material, dead things, and even feces.  One other cool fact– paternal care has evolved in 5 independent lineages of Opiliones (Machado 2007).

Fluourescent Scorpions: Love and Danger in the Dark

8 Feb
Scorpions fighting at night in the desert, viewed with a blacklight.

Scorpions  at night in the desert, viewed with a blacklight.

One of the coolest night collecting tricks is to take a black light out to look for scorpions.  In the desert (and even in the woods where I live) these cryptic stinging critters emerge at night to hunt, and although they are well camouflaged a simple black light reveals them in glowing color.  There’s a lot of debate about why scorpions fluoresce under ultraviolet light but it may be a further mechanism to help them avoid light (which makes them vulnerable to predators and dehydration).

Scorpions that are not hungry reduce activity on brightly moonlit nights.  Being able to detect and head towards dark areas can also help an organism with relatively poor eyesight to quickly identify refuges such as rocks and bushes (Camp & Gaffin 1999).  Gaffin et al. found that, when blindfolded, scorpions could use their entire exoskeleton as a sensor to detect UV light (2011).  I am now enjoying picturing scorpions in tiny blindfolds.

Two scorpions fighting in the desert at night.

Two scorpions fighting (or courting?) in the desert at night.

I encountered this particular pair of scorpions in the desert in Arizona.  At first I thought they might be engaged in courtship behavior, but later I thought they might just be fighting (possibly both?).   Yes, I know the pictures look a bit violent with the wrestling and the stinging, but scorpion courtship is, well, probably only fun for scorpions.  I can’t find the excellent clip from Life in the Undergrowth, but there are some lovely videos of scorpion mating dances on Youtube.  For many species, stinging is involved.  Also elaborate dancing, and chewing on each other’s faces (“kissing”).  The courtship is completed when the male manuevers the female backwards onto a spiky spermatophore he has placed on a flat surface.

Scorpion chews on the face of a smaller scorpion with its chelicerae while pinning its telson in a claw.

Two scorpions: fighting or making out?

 

Giant Jumping Spiders

18 Jan
Paraphidippus basalis, a cousin of the bold jumping spider.

A large jumping spider from the Arizona desert.

I ran into this lovely individual while attending the Ants of the Southwest course at the Southwestern Research Station in Arizona.  I’ve always had a soft spot for the charismatic jumping spider, and the widespread bold jumping spider –similarly marked in Halloween orange and blacks– is one of my favorites (and one I’ve posted about here before).  The spider pictured here, however, has the distinction of being easily the biggest jumping spider I’ve ever seen.

Black and orange spotted jumping spider on arm.

Paraphidippus basalis jumping spider on a human arm for size reference.

In fact, this individual turns out to be a close cousin to the bold jumping spider, a member of the genus Paraphidippus (“beside Phidippus”) rather than the genus Phidippus.  Other than that, I can’t find much information about P. basalis.  There are pictures of it tagged from Arizona and New Mexico, and Discover Life’s only data point comes from the New Mexico biodiversity collection.  Two people on Bugguide report finding it on agave plants in Arizona (mine was found crossing a trail in the vicinity of agave).

This spider may also look familiar to you for other reasons:  According to Wikipedia, its more common sister species, Paraphidippus aurantius, was the model for the giant mutant spiders that terrorized the Arizona mining town in the humorous horror movie Eight Legged Freaks.

Jumping spider attacks cop car in Eight Legged Freaks (photo via IMDB).

Jumping spider attacks cop car in Eight Legged Freaks (photo via IMDB).

Spiders raiding ant nest

3 Sep
Spider predating on Pogonomyrmex nest at night.

Spiders slip inside a sleeping harvester ant nest to prey on the worker ants.

Last week I had the pleasure of attending the new Ants of the Southwest course at the Southwest Research Station in Arizona, and I thought I’d jump right and share with you my favorite entomological encounter.  While black lighting in the desert we happened across a harvester ant nest that was being raided by dozens of small hungry spiders.  The spiders would slip inside the nest entrance individually and emerge some time later, dragging worker ant prey.   It was pretty impressive to watch, particularly as there was no evidence that the spiders’ raiding was provoking any kind of response from the colony.  Harvester ants (or “pogos,” from Pogonomyrmex) are a group of ants with a fairly vicious sting, and the workers dwarfed their tiny spider predators.

I’ve included more pictures as well as a video below, with bonus excited chattering commentary.

Spider entering Pogonomymex nest and killing workers.

A spider drags its harvester ant prey from the sleeping nest.

I don’t have an ID for the spider as of yet.  Several group of spiders are known to mimic ants, either to help them obtain prey or to help them avoid predators.  If these spiders don’t look like ants to you, it’s possible they may smell enough like ants to fool the colony.  Cosmophasis jumping spiders use this scent-disguise tactic to enter weaver ant nests and prey on workers and larvae.  Meanwhile certain spiders in the genus Masoncus take this a step further and live only inside harvester ant nests, where they prey on another nest symbiote, collembolans.

Spider feeding on its harvester ant prey.

A spider hangs from a grass blade, feeding on a harvester ant many times bigger than itself.

Update:

Thanks for the feedback here and over at Bugguide.  These spiders appear likely to be members of the family Theridiidae and the genus Euryopis.  Many members of this genus appear to be specialist predators of ants.  I poked around in the literature and there are a couple of papers about the species E. coki, a specialist predator of another species of harvester ants, Pogonomyrmex owyheei.  (I believe the harvester ants pictured above were P. maricopa.)  There were a number of similarities to the behavior I observed.  E. coki was observed to lurk outside nest entrances and ambush ant workers, first tacking down a leg with silk and then biting the ant.  When bushes or grasses were nearby the spiders employed a dangling feeding behavior (Porter and Eastman 1982).  Dale Ward has a great shot of a male Euryopis mating with a female spider near the nest entrance of P. rugosus.  Tetramorium’s Ants of Arizona page also has some great shots and info.  I haven’t been able to find any literature on thespiders actually entering the ant nests, though.

Wiggle Wiggle Wiggle

25 Jun

Here’s one more picture of the mama wolf spider from last week that I kind of liked even though it was taken through plastic of the container:

Lycosidae mother wolf spider with babies on back.

Also, so that you can enjoy the full effect I made a little animated GIF for y’all to enjoy:

Wiggle wiggle wiggle

Spider Piggy-Back Rides

22 Jun
Lycosidae wolf spider mom with eggs

Wolf spider mother with egg sac.

I picked up this large mama wolf spider with her egg sac while out doing field work.  The trip home apparently disturbed her, because I was disappointed to see she dropped her egg sac and apparently abandoned it.  Then a few days later it vanished.  Then she constructed a refuge of webbing coated in dirt and debris and closed herself in.  A few more days later I noticed she had an egg sac again–and it was bigger than ever.   Intrigued, I sent the picture above to friend and former post-doc in my lab Shawn Wilder.  Shawn introduced me to working with fire ants and also happens to have done his Ph.D. work on sexual cannibalism in wolf spiders.

Shawn had this to say:

Beautiful spider.  It looks like the genus Hogna, most likely Hogna carolinensis (they’re one of the more common big Hogna in Texas).   I studied Hogna helluo for my Ph.D. but they’re not quite as pretty as carolinensis because helluo doesn’t have the mottling on the legs.
That’s typical Hogna behaviour.  They will build a silk-lined burrow and will eat their egg sacs if they lose sight of them and refind them.  It looks like she is trying to warm up her egg sac in the sun. That’s a mega-huge egg sac she has.  It should be very fun when the babies crawl out and onto her body because when there are tons of babies the mom has to use her pedipalps like windshield wipers to keep the babies away from her eyes!
I had managed to completely forget that wolf spider mothers carry their babies around on their backs so I was pretty psyched.  And mama spider delivered this week.
Lycosidae piggy back rides from mom.

Mother wolf spider with a back full of baby spiders.

Shawn also pointed out that the spiderlings don’t need to eat at this point.  For a week or two they ride around on their protective mother, clinging to special barbed hairs, and then gradually begin to disperse.  Every so often a few spiderlings will drop off and walk away from the mother, providing a very effective way for the young to disperse over a wide area in nature.  Of course, if sufficiently disturbed the spiderlings may scatter early–probably accounting for urban legends of wolf spiders that “explode into little spiders” when stepped on.

Lycosidae spider covered in little spiders.

Close up of mother wolf spider carrying babies.

Lycosidae newly hatched wolf spiderling on finger.

One of the spiderlings explores a finger.

Lycosidae Baby Wolf Spider

Newly emerged wolf spiderling under 80x magnification

Zebra Spider

18 May
Close up of black and white striped zebra jumping spider.

Stripey zebra jumping spider.

Here’s a particularly adorable jumping spider I found being adorable on a dead tree by the Red River in Oklahoma.  Like most jumpers this fellow did not want to let the camera get close–I’ve cropped the above photo way down so we can all admire his stripey splendor.  This is a member of Salticus, the zebra jumpers, so called for the black and white stripes seen in many species.

This particular species (Salticus austinensis Gertsch; Det. Joe Lapp, 2012) is a conspicuous predator, with an active period in the brightest part of the day that is shorter than many similar jumping spider species it cohabits with.  They prefer large, vertical foraging areas such as walls, rocks faces, or in this case, the broad flat side of a dead tree.  Such well lit, open expanses may help them avoid ambush predators.  (Horner et al 1988)

Zebra striped black and white jumping spider on swirly tree bark.

Jumping spider against tree bark.