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Christmas Mystery Cocoon

25 Dec

In honor of Christmas and the season of giving I bring you this mystery stocking stuffer, encountered in Argentina.

First, the present all wrapped up and hung on the tree.

Peeking inside...

Removing the first layer of wrapping...

The mystery present all unwrapped.

Ta-dah!  Your present seems to be some kind of hymenopteran pupae.  And if you can tell me what they are, that will be my present.

…merry Christmas and happy holidays, y’all!

Lots and lots of leafcutters

19 Dec
Colony of leaf cutter ants

A busy crowd of polymorphic leaf cutter ants at a large nest entrance.

Leafcutters are one of the most striking ants I’ve encountered, with their giant spiky bodies and stilt legs.  Unlike most other ants, leafcutters no longer retain the ability to sting or spray venom.  These ants are specialized for doing what their name implies–cutting leaves–and this can be seen clearly in the powerfully-jawed major workers.  In fact, the jaws latch on so strongly, staying clenched even after death, that beheaded workers are sometimes used to close wounds.  While in Argentina, my labmate Paul tried this out on a papercut.  Cure possibly less pleasant than the ailment.  Very effective, though.

Leafcutter ant heads used to pinch a cut closed.

Leafcutter ant heads used to pinch a cut closed (Photo courtesy P. Lenhart).

In my occasional encounters with leafcutters of the genus Atta, I was particularly impressed by the truly gigantic, sweeping nests a single colony can make.  Although not particularly tall, these mounds can cover a lot of ground, littered with cast off plant material and abuzz with busily working ants.  Apparently the 10-15 foot mounds I’ve seen don’t even come brush the upper limits:  Wikipedia says the central mound can grow to more than 100 feet across.

Giant ant hill of leaf-cutter ants.

Paul Lenhart observing a large mound of Atta leaf cutter ants in Argentina.

I’ve hardly ever encountered leafcutters in my area of Texas, but there is one large colony of Texas leafcutter ants (Atta texana) deep inside our local Lick Creek Park if you know where to look.

Related posts:

Ant farmer – Leafcutter Ants

Leafcutters on Parade

First, Remove Cat from Ants

21 Nov

Fire Ant Treatment Step 1: REMOVE CAT (source: GotoAID)

I have updated my Things That Are Not Fire Ants page with 7+ new pest control sources.  Check it out!

In the course I stumbled across the above illustration for treating fire ant bites in cats which may be one of my favorite “fire ant” graphics of all time. Caption:

Step 1: Make sure you remove yourself and your cat from any fire ants and gently hose off ants if you need to get them off your pet.

GoToAID looks like a useful first aid resource, plus it has the added bonus of (presumably) unintentionally hilarious 3D rendered graphics.

I’m sold!

Dancing Ant

11 Nov

All I have for you today is this dancing acrobat ant.  They’re supposed to live in trees but sometimes they come in the window and hang out on my desk.  Please enjoy.

The Mummy – Aphids and Parasitoid Wasps

2 Sep
The remains of a parastized aphid mummy complete with wasp larva escape hatch.

The remains of a parastized aphid ("mummy") complete with parasitoid escape hatch.

My labmate Collin found mummies in his aphid colony.  It was kind of exciting, although maybe not up to horror movie standards.  Mummies are what happen to aphids when a parasitic wasp injects them with an egg.  As the wasp larva grows inside their bodies, feeding on their hosts, the still living aphids swell into pale, bloated, unmoving forms on the leaf surface.  Eventually, adult wasps burst from their hosts, leaving behind the kind of gruesome sight pictured above.

Close up of cotton aphid (Aphididae) feeding on cotton leaf.

Close up of cotton aphid (Aphis gossypii) feeding on a cotton leaf.

For comparative purposes, here are pictures of a healthy, live aphid, as well as the shed skin of an aphid following a molt.  For a frame of reference these guys are about a millimeter or two long.

The shed skin of a cotton aphid (Aphis gossypii).

Cotton aphid exuvia (cast off exoskelton) on a cotton leaf.

Special thanks to Collin McMichael for helping me with the digital microscope photography.  And thanks also to someone who featured a how to on manual focus stacking in photoshop a while back.  I cannot find this post again for the life of me.  There was a picture of an ant with a parasitoid I think.  It was awesome.  I have been wanting to try this technique for a while, so it was fun to experiment.  I should probably get a shot with the legs in better focus in the future.

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.

Thirsty Bugs

15 Jul
A thirsty honeybee (Apis mellifera) struggles after falling into the water.

A thirsty honeybee struggles after falling into the water.

It’s been a hot, exceedingly dry summer here.  In the African savannah, wildlife congregate at watering holes.  Here in Texas cattle land we have watering troughs.  These oases in the desert are not only attractive to the larger lifeforms, but their smaller six-legged compatriots as well.

During a very dry visit to the gorgeous Elephant Mountain Wildlife Management Area for EntoBlitz, the effects of the drought could be observed in the multitudes of thirsty honeybees seen clustering along the interior lip of a water tank.  Like the African watering hole, the tank wasn’t without its dangers:  as in the case of the unlucky bee above, who lost her footing and became ensnared by wet wings and clinging surface tension.

Honeybees drink water while one falls in.

Thirsty bees cling to the interior lip of a water tank during a drought (Elephant Mountain Wildlife Management Area, Texas).

Many thanks to Paul Lenhart for the pictures!  (And surprise to Drew, who didn’t know I was going to stick this picture on my blog.  Hi, Drew!)

Ant Bridge – Video

11 Jul

Video of the floating fire ant bridge, as promised.  The music is a bit odd, but I couldn’t resist.  🙂

Ant Bridge

8 Jul
A raft of flooded out fire ants (Solenopsis invicta) forms gradually form a path across the water.

A raft of flooded out fire ants gradually form a path across the water.

A few weeks ago we had a big downpour after a long dry spell.  A&M’s an old campus and doesn’t drain well, so a number of sidewalks and fields were temporarily flooded.  Walking along one of these sidewalks I spotted a fire ant colony that had flooded out into three large rafts of stranded ants.  This rafting behavior is a natural adaptation of fire ants to survive flooding, wherein the workers form a living floatation device to preserve their fellow workers, brood, and queens.

Flooded fire ants (Solenopsis invicta) form a living bridge to dry land.

Flooded fire ants form a living bridge across the water to dry land.

I went home to get my camera, and by the time I returned that afternoon, the rafts of fire ants had managed something I haven’t seen before.  They had spread out and connected up to form a living bridge across the water to dry land.  Ants ran back and forth along a path composed of their living sisters, while those at the surface of the water tested the area ahead with their antennae.  On land a trail of ants was busily moving brood into the dry refuge of a light pole.

An elite pest control agent battles a tentacle of sentient ants with a laser (Source: The Hive).

The reaching trails of ants called to mind a sci-fi/horror film wherein a sentient supercolony of ants formed huge hovering tentacles to drag the humans’ boat to shore.  The pest control people had lasers.  It was a pretty awesome film.  Actually, if you haven’t seen the movie The Hive I highly recommend it, if only for the bizarre plot and ridiculous pseudo-science.   Also, the best movie quote ever:

“We are NOT going to negotiate with ANTS.”

Fictional movies aside, reality is pretty impressive all on it’s own.  I took a whole bunch of pictures of the bridging fire ants, as seen below.  I took some video, too, so hopefully I’ll get that posted when I get the chance to edit something together.

Close up of rafting fire ants in a flooded field.

Forking trail of floating fire ants.

Two isolated rafts of fire ants converge to form a bridge to dry land.

Close up: A floating aft of fire ants bridges a flooded field.

A living raft of fire ants bridges a flooded field. To the right, an alate is visible traversing the bridge to safety.

Related posts:

Nuptial Flight – The Sad Plight of Male Ants

24 Jun
Winged sexual male and female sugar ants prepare for their nuptial flight under the guard of the small black worker ants.

Male and female alates prepare for a mating flight while worker ants stand guard (Brachymyrmex).

Earlier this week I was treated to my mailbox colony of Brachymyrmex (no official common name, but around here we call them sugar ants*) throwing a mating flight party.  They live in the bricks of the mailbox, so the whole exterior was aswarm with the winged male and female sexuals (alates)  as well as an abundance of defensive workers, guarding the reproductives as they prepared for their flight.  I was particularly taken with the tiny frenetic males, who were adorable in their yellow-orange splendor and half-pint size.

Winged male sugar ants (Brachymyrmex) swarm in preparation for a mating flight, under the guard of workers.

Winged male sugar ants (Brachymyrmex) swarm in preparation for a mating flight, under the guard of workers.

In most species, male and female sexual ants are fairly easy to distinguish.  While both genders have enlarged thoraxes to host their wing muscles, the females, who will go on to be queens, tend to be larger, with swollen abdomens the better for mass-producing eggs.  The males, on the other hand, are essentially one-time sperm-transfer units.  They will mate (if lucky), and then die.  In this simple role, they don’t need all the complicated mental circuitry of the future queens, so they also tend to have smaller heads.  As the joke goes: Big shoulders, tiny brains:  that’s how you know they’re males.

Sexual male and female sugar ants (Brachymyrmex) with sterile worker ant.

Sexual male and female sugar ants (Brachymyrmex) with sterile worker.

*edit:*  Thanks to Danny McDonald for pointing out the the common name ‘rover ant.’  The Brachymyrmex species B. patagonicus is invasive in the United States and becoming an increasingly common nuisance pest in households.

Also check out Alex Wild’s excellent pictures on Myrmecos, including a mating pair.