Feeds:
Posts
Comments

Archive for the ‘Uncategorized’ Category

Image Gallery Down

Smugmug, the host for my image gallery alexanderwild.com, has been down all morning.  The problem is apparently serious and resolution may take a while.

I apologize for the inconvenience.  If there was a particular image you were looking for this morning and now you can’t get to it, email me.

dead

*update 12:15pm; we’re online again!

Read Full Post »

exsectoides12

Formica exsectoides carries off a seed of a non-native plant, leafy spurge

Ants are considered beneficial insects for their roles as predators, scavengers, and dispersers of plant seeds.  But when the seeds belong to a pest plant, the ants’ role may change to that of accomplice in an unwanted biological invasion.

Moni Berg-Binder, a student in the Suarez lab at the University of Illinois, is studying the interaction between native Formica ants and an invasive euphorb, leafy spurge.  Leafy spurge seeds have an edible elaiosome that ants find attractive enough to carry back to their nests, so the ants may be assisting the plant as it spreads across the great plains of the central United States.  Moni was kind enough to arrange the ants and the seeds for this photo shoot.

The white bit at the tip of these leafy spurge seeds is the elaiosome, a structure that attracts ants.

The white bit at the tip of these leafy spurge seeds is the elaiosome, a structure that attracts ants.

exsectoides13

A tasty snack to carry back to the mound?

Read Full Post »

and gives us a list of photography’s advantages over specimen collection:

  1. You don’t need permits to take images.
  2. You can take images of wildlife and people (you can’t “collect” those!).
  3. Storage of images takes a lot less room than storage of an insect collection.
  4. It takes less time to prepare an image than a specimen (that may change as I get more sophisticated).
  5. You can share images (I can’t pin an insect specimen to my blog).
  6. Photography makes you more observant.
  7. Images of living organisms are more colorful and robust than faded, withered dead specimens.
  8. You can record behaviors in a photograph.
  9. You can record habitat in an image.
  10. Carpet beetle larvae can’t eat my hard drive.

Read Full Post »

Great to see Alex back, and with such a beautiful shot. I had a little post ready, so I figured I would go ahead and put it up. Maybe it will give Alex a little bit more time to recuperate after what sounds like a tough journey back.

One of the things I have discovered about studying a diverse arboreal group in a system that allows such easy access to the canopy is that undescribed species are relatively plentiful. In my main cerrado site, I have 17 Cephalotes species and 3 of them are undescribed. In my fist study at a second site, just 30Km down the road, a fourth new species showed up. All of these species are exciting in their own way, but one is particularly striking. I thought I would share a few shots with you. The main point of interest that I wanted to talk about is the coloration, and particularly the eyespots in the gyne.

c_unknown1

Why might these eyespots be there? Well, evidence suggests that Cephalotes are quite distasteful, so the best explanation is that this is some kind of aposematic coloration. While eyespots are remarkably rare in ants as a whole, they are quite common in Cephalotes. In my experience, though, they are rarely this pleasing to the human eye (or at least this myrecologist’s eyes). After mating, Cephalotes gynes roam the canopy in search of a suitable cavity to start their colony. Hanging out in trees for a couple of years, I have seen this searching behavior many times, but never managed to get a decent shot of it (unlike more talented photographers).

The soldier caste has a similar coloration to the gynes. While this could be nonadaptive developmental spillover from the gyne (it fades out in smaller members of the soldier caste), it may also have some adaptive value. Soldiers, the relatively rare and expensive sterile caste, shuttle between the colony’s various nests on a daily basis, so the eyespots may help ward off possible predators while they do it.

c_unknown2

As for what I should call this gorgeous ant, I have a few ideas, but I would love to hear what you all think in the comments.

Read Full Post »

…We had reached the top village, we had sifted great quantities of Wasmannia-free leaf litter, and we had learned the local lore about the Kakamora dwarf people that lived in the forest and granted magical powers to those with the prowess to catch one. Meanwhile, the full week of wet shoes and socks was causing our feet to disintegrate at an alarming pace.
Foot rot.

Foot rot.

The day’s hike back down to Hauta village had been excruciating, and keeping one’s balance going down the muddy track was even more difficult than climbing it. We had gotten a few small myrmicines that we thought might be Lordomyrma, but instead turned out to be a variety of Vollenhovia species. Vollenhovia, like several other genera, has diversified into a remarkable number of species in the Solomons.
Another genus that was always thrilling to find was Leptogenys. True army ants do not occur on the archipelago, so other ground dwelling ants have done their best to fill the empty “insatiable marauder” niche. A few different species of Leptogenys manage an earnestly believable impersonation of the real deal, and strong rivers of the ants are occasionally seen streaming across the trail, cascading into ever smaller rivulets until the frontier of their trajectory is a wide wash of scrambling chaos. The species below, which I believe is undescribed, was found nesting under a stone. It wasn’t Lordomyrma, as I had hoped for, but the find did afford me a brief respite from the foot agony.
Leptogenys sp.

Leptogenys sp.

I hadn’t given up on Lordomyrma, though, and plucked up the courage to spend an hour collecting the banks of a small stream near our lunch stop. Every step felt like stepping on coals, but stream banks always seemed to be a good bet for Lordomyrma in my trips to Fiji and New Guinea. Although the little beasts were not to be found, there was an impressive colony of Pheidole (pictured below) that was nesting between the cracks of the stone river bank, spewing forth hordes of minors and majors while victorious huntresses filed back with all manner of arthropods wriggling between their mandibles. The sheer numbers and vigorous activity of the species reminded me again of the absence of true army ants, and the gaping ecological niche that a particularly enterprising species might get a piece of.
Pheidole sp.

Pheidole sp.

I went barefoot through the jungle for the last day of the trek out. The occasional sharp root or twig or leaf was preferable to the sensation of socks rubbing against the exposed under-layers of raw skin. Walking barefoot through the jungle is usually not the most advisable undertaking, but in the Solomons one at least has the comfort of knowing that no poisonous snakes lurk coiled by the trail. The going was rough, but we made it to the river in time to catch the canoe down to the mouth, in time to catch the truck back to the sleepy town of Kirakira.
Of all the stones we turned over, of all the logs we hacked to bits, of all the forest litter we methodically sifted, we ended up with one solitary single worker of the Solomons’ Lordomyrma. The little ant now rests safe and sound in an insect drawer, its DNA having been digested and digitized. I’m fairly certain that if I hadn’t gone barefoot that last day, the jungle would not have granted me that true token of reward. Getting the good things in life takes a little sacrifice.
Bye!

Bye!

Read Full Post »

Cephalotes pusillus is ever-present in cerrado. In fact, I have never encountered another ant that is so abundant in a natural system, tropical or temperate. They are generalist nesters and can be found in almost every piece of standing dead-wood and many live trees. The workers are particularly robust, even for Cephalotes, and will often bulldoze their way to foods already overwhelmed by other ants.

C. pusillus worker

But even for these tank-like ants, trouble lurks in a surprisingly familiar form. The aphantochilid spider Aphanlochilus rogersi is a very striking mimic of C. pusillus, but not for the purposes of protection. It is an infiltration tactic. A spider will sit on the edge of a foraging trail of its model, seemingly undetected by the ants. When one worker strays too far off the beaten track, the spider strikes and runs with its prey before the large and dangerous foraging force has time to react. These spiders are remarkably abundant…but very fast. It took me a good year to get this shot of one of these hunting mimics with its prey and model.

lunch

The ant-mimicking Aphanlochilus rogersi with a paralyzed worker of its model, Cephalotes pusillus. This shot is on the underside of a branch. The foraging column from which the C. pusillus worker was plucked was on the upper surface.

For those wanting to read more, there is a nice older paper on this interaction (Oliveira, P.S. & Sazima, I. 1984. The adaptive bases of ant-mimicry in a neotropical aphantochilid spider (Araneae: Aphantochilidae). Biol. J. Linnean Soc. 22: 145-155.)

Read Full Post »

…By the time we reached the the top of the mountain, Wasmannia had disappeared from the old growth forest and the native fauna appeared to us as it must have appeared to W. M. Mann the century before. Yet what the forest gave to us in specimen rewards, it took from us in bodily harm. The second day forced us across the river six times before we could begin our ascent up the mountain. Even if we hadn’t crossed so many times, the constant deluge would have left us just as soaked. Rain coated the steep mud trail with a frictionless layer of slip, causing Evan, Jon and I to perform a fine stooge routine as we fell one after the other in complex patterns of synchronicity. We are ants climbing a fluon-rimmed tub I meditated, searching for in vain for clean spot of pant leg upon which to rub muddy hands.
A small highland village between Hauta and Marone

A small highland village between Hauta and Marone

The local fellows did the entire hike with hands holding our bags and 20 kilo bags of rice — their feet bare of shoes —  just as we might stroll down a neighborhood street. What for us was a will-bending, bottom-bruising, eight hour struggle was literally the two hour walk home from school for the village children. All the houses built atop the mountain were constructed from forest materials or hiked up 800 meters on the backs of men and women.
A typical wooden house in Marone village. All building suplies must be brought in by hand over a treacherous 800 meter ascent.

A typical wooden house in Marone village. All building suplies must be brought in by hand over a treacherous 800 meter ascent.

The mud, humiliation and bruises were well worth the fine hauls of ants our party was bringing in. Although I kept one eye out for small dark myrmicines that smelled like Lordomyrma, the bread and butter of this expedition was  Malaise trapping and Winkler sifting. Malaise trapping involves pitching tent of insect fabric specially designed to funnel intercepted insects into a collecting bottle at the apex of the roof, and then down into a puddle of 95% liquid doom. Malaise traps are an excellent way to passively collect the arboreal ant fauna without having to climb trees. It’s kind of like sticking your fishing pole between a couple of rocks and putting it on autopilot while you knock off for a few beers.
Setting up a Malaise trap with Jon Fassi.

Setting up a Malaise trap with Jon Fassi.

Only, we didn’t have any beers. What we did have were Winklers (or “winkles” to use a term of more intimate endearment). What Malaise traps are to arboreal ants, winkles are to ground dwelling ants. The idea here is to chop up a square meter of forest litter with a good sharp nasty looking bush knife, prey there are no Odontomachus down there, then toss the goods into a tied off bag with a section of 1/4″ screen in the middle.
You shake the dickens out of the rotting leaves and humus and downed twigs until your arms hurt, admire the ounce of particulate matter collected at the bottom of your bag, think about how many eye-popping arthropods are scrambling about down there, then convince your field assistant its his turn to do the next shake. Back at camp you fill up mesh bags with the sifted litter, hang those in an extracting bag, and watch as ant after ant crawls out the mesh and lands in a puddle of 95% doom.
Evan preparing Winkler extractions.

Evan preparing Winkler extractions.

There are a couple dangers of winklin’ in the rain. The first is that all the ants stick to the mud. The second is that the big nasty sharp bush knife gets slippery and the blade occasionally slices through your sock and opens up your shin. When your local guide roots around the jungle for a certain vine and squeezes the milk out into your wound, that’s when you just have to pray he knows what he’s doing. Not that ANYTHING like that happened on this expedition, though…

Read Full Post »

Older Posts »