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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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May Taxonomy Fail: Insect Tattoos

24 May
insect tattoo art book

And when they say “insect” they mean…

It’s been a while since I’ve posted a good taxonomy/morphology fail.  This one’s got a little of both.

A friend gave me this wonderful little booklet of temporary “insect tattoos” a few months back, and my fellow entomology graduate students and I had a lot of fun picking out which tattoo best suited each of us.

As you can see from the cover, this collection played fast and loose with the definition of “insect.”  (Wait, scorpions are insects, right?)

Something is awry with this spider.

Something is awry with this spider.

My personal favorite was the tarantula.  At least, I’m assuming that’s what it was.  You can see the artist has made the common mistake of counting the pedipalps (essentially a leggy sort of mouthpart) as a pair of legs.  This would-be arachnid has, not eight, but six legs.   It seemed appropriate.

As an alternative theory, perhaps they were trying a little too hard to fit the spider into the “insect tattoo” classification.

I wore it with pride.

I wore it with pride.

 

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

May Taxonomy Fail: Everybody wants to be an ant

28 May

Here’s a fun one for my bug blooper series of mislabeled and misidentified bugs from around the interwebs.

Drumroll, please….

“Fire Ant”

Ta-dah!

This is a very cool one.  Take a close look, because I love these little guys.  This is not a fire ant.  And it’s not an ant.  This is a nifty little ant-mimicking spider.

Some very cool ecology here.  Ant mimicry is fairly widespread in the arthropod world.  In some cases it allows predators to blend in with ants–either to steal their prey or assasinate and devour the ants themselves.  In many cases, however, this mimicry serves a defensive purpose.  When you’re a centimeter long, looking like an ant makes you a bad ass.  For example, check out this ant-mimicking mantis nymph:

Nobody’s messing with him.  For more great photos check out  Up Close With Nature’s  excellent post on ant mimicry.

—-

“Fire ant” spider via Connemara Conservancy Meadow Tour Guide

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.

Meal Time

30 Sep
Crab spider eating a mirid.

Crab spider devouring a web-wrapped plant bug (Miridae).

Just a random picture of a crab spider with a mirid lunch all wrapped up.  Plant bugs seem to be a popular lunch item in my neck of the woods. Of course, they’re the largest true bug (Hemiptera: Heteroptera) family, mostly herbivores, and conveniently snack-sized.

A Heap of Queens – Foundress fire ants

26 Aug

Fire ant alates pile up on a sidewalk after a rain.
We finally had rain again.  I think it has rained twice this summer.  And with the rain come fire ant queens!

Fire ants mate in nuptial flights hundreds or thousands of feet in the air.  They use environmental cues to both synchronize mating flights with other colonies and ensure that conditions are good for founding new colonies.  This means that the afternoon following a rain (particularly if it’s been dry for a while) hundreds and thousands of newly mated queens can be found wandering the ground in search of a good nest site.  (The dying males are also in abundance.)  The foundresses may start colonies alone, in groups, or even join existing colonies.  In the meantime these ants explore every available nook and crevice which may provide both refuge and a good start on a nest tunnel.

Winged sexual fire ants cluster together

A pile of newly mated fire ant foundresses is revealed from under a twig.

The alates are easiest to find in areas where they have trouble going to ground.  For instance, on a hard gravel pathway or a paved road you may turn a leaf or a stone and find a dozen queens wedged underneath.  In some cases, like the picture at the beginning of this post, I have even found piles of fire ant alates apparently attempting to hide under each other (or at least conserve moisture).  When not hiding, the wandering alates are  easy to spot due to their large, shiny abdomens and awkward, trundling walk.

Male alate (Solenopsis invicta) is predated by jumping spider following a mating flight.

A jumping spider (Salticidae) devours a male sexual fire ant.

The sudden surge in these slow, mostly defenseless sexuals (the queen’s stinger/ovipositor is modified for egg-laying) makes a tasty meal for many predators.  Don’t think a queen is completely helpless however.  I’ve personally observed a foundress with an egg clutch tear a dozen invading fire ant workers limb from limb with her mandibles alone.