Can ants count? Not out loud they can’t. Not the way you and I count. But an ingenious experiment conducted in the Sahara suggests maybe ants do count.

How Do Ants Get Home?

Most ants get around by leaving smell trails on the forest floor that show other ants how to get home or to food. They squeeze the glands that cover their bodies; those glands release a scent, and the scents in combination create trails the other ants can follow.

That works in the forest, but it doesn’t work in a desert. Deserts are sandy and when the wind blows, smells scatter.

So how do desert ants find their way home?

It’s already known that ants use celestial clues to establish the general direction home, but how do they know exactly the number of steps to take that will lead them right to the entrance of their nest?

Wolf and Whittlinger trained a bunch of ants to walk across a patch of desert to some food. When the ants began eating, the scientists trapped them and divided them into three groups. They left the first group alone. With the second group, they used superglue to attach pre-cut pig bristles to each of their six legs, essentially putting them on stilts.

Scientists put stilts on desert ants and discovered that in time, the ants could calculate the correct number of steps it took to get home.

The third group had their legs cut off just below the “knees,” making each of their six legs shorter.

After the meal and the makeover, the ants were released and all of them headed home to the nest while the scientists watched to see what would happen.

The “Pedometer Effect”

The regular ants walked right to the nest and went inside.

The ants on stilts walked right past the nest, stopped and looked around for their home.

The ants on stumps fell short of the nest, stopped and seemed to be searching for their home.

It turns out that all the ants had walked the same number of steps, but because their gaits had been changed (the stilty ants, like Monty Python creatures, walked with giant steps; the stumpy ants walked in baby steps) they went exactly the distances you’d predict if their brains counted the number of steps out to the food and then reversed direction and counted the same number of steps back. In other words, all the ants counted the same number of steps back!

Does that mean ants have something like pedometers that do something like counting?

Says professor James Gould of Princeton, commenting on the experiment: “These animals are fooled exactly the way you’d expect if they were counting steps.”

Gould says it’s pretty clear ants don’t have maps in their heads and don’t recognize markers along the route. This experiment strongly suggests that ants do have internal pedometers that allow them to “count” their way home.

Special thanks to OddTodd, our animator, and to comedian Jessi Klein, who provided ant voices in our video.

Check out this youtube slideshow of some beautiful bugs (butterflies and stuff)

http://www.youtube.com/watch?v=pTQZAiuDoTg

“Butterflies are self propelled flowers.”  ~ R.H. Heinlein

Yes, well, could someone please identify this butterfly? The butterflies at my parents house this year were quite prolific. Especially this variety. I don’t think its a monarch, orange/brown color wasn’t quite as bright and no defining black lines.

Who said DoTW! could only do human diseases? Why are you so special huh? Insects get sick too and someone has to care. I care. Also, by showing some sympathy about insect diseases maybe I will survive the invasion and subsequent enslavement of the human race by our most welcome and superior Insect Lords. I pledge to humbly serve thee.

Feed my Lord, grow strong

So why an insect pathogen?

Well, it’s fun to be different I guess. Also the bacteria I’m going to discuss, Photorhabdus luminescens, is fun to say. They also happen to be really interesting for a bunch of reasons:

• Can’t cause disease in insects without help from a friend
• A classic example of symbiosis
• Referred to as the ‘Angel Glow’, or something similar, by ‘the wounded’ anytime before World War II

See I told you they were interesting.

Photorhabdus: the bane of our insect overlords

We haven’t spoken much about life-cycles on the previous posts because generally we have been dealing in human pathogens which, for the most part, struggle to exist and cause disease in anything but humans. This life cycle is very simple human-human-human etc. Other pathogens such as the causative agent for malaria are spread by mosquitoes so the life cycle is more complicated. For Photorhabdus we have a very intriguing life cycle indeed.

Photorhabdus are a group of bacterial insect pathogens but other than that are not particularly fussy. This fact alone is quite interesting. Most pathogens have specialised to infect one or a small group related animals. There are few pathogens that can infect, say, all mammals equally. The other thing unusual about how the infection takes place is that the bacteria cant do it on their own, they require the assistance of a ‘taxi’ nematode (a family of multi-cellular, micro-organisms, look a lot like a microscopic worms in most cases) called Heterorhabditis. The nematode enters insects and proceeds to regurgitate the bacteria, which live in its intestine, into the insect. The bacteria thrive in the insect and quickly multiply and grow. During this time the nematode begins feeding on the bacteria whilst also growing and multiplying. Once the insect has died and its cadaver is entirely hollowed out the nematodes stop feeding on the bacteria and move off to another host, where the process starts again.

This figure shows the location of the bacteria (in fluoro green) at the various stages of the nematodes life cycle. If you like the pretty picture than that’s great, if you want a better explanation of what’s happening in the pics see the Waterfield et al. reference at the bottom.

Why would the bacteria and worm have developed this relationship together? Surely it would have been easier for the worm to evolve the ability to feed on the insect directly, and wouldn’t it make more sense if the bacteria didn’t grow just to be eaten by the worm again? This is where the classical model of symbiosis I mentioned comes in.

Symbiosis is observed when two dissimilar organisms actively co-exist, most often to the benefit of both organisms. When both organisms benefit from co-existing together it can also be called mutualism. In this case the bacteria in the environment are not guaranteed nutrients on which to grow, neither are nematodes. By working together they can each ensure their own survival as they now ‘rely’ on each other. In fact the nematode has evolved with such a preference for Photorhabdus feeding that now it absolutely requires it. This produces an interesting problem for the nematode, the insect is harbouring other bacteria which are potentially toxic to it. How can it ensure it only eats Photorhabdus? Lucky for the nematode the bacteria are on the case.

Upon being regurgitated the bacteria start to produce a range of anti-microbial factors that inhibit the growth of other bacteria. These include a family of bacteria specific toxins called pyocins. But how can the bacteria make sure they get eaten by Heterorhabditis and not some other worm? Again the bacteria have ‘thought’ about this. They also produce a number of molecules that kill nematodes, but not Heterorhabditis.

So the bacteria protect the worm from eating the wrong bacteria and also ensure it can only be eaten by the right worm. Pretty smart huh?

Well they have one more trick, and it’s awesome. They glow.

Why? We’re not actually sure but one of the strongest hypotheses around currently is that once the bacteria are present in very large numbers, like when the current insect corpse is running out of flesh, the glow of the large number of bacteria together attract other insects to the corpse, making the transition from the ‘spent’ host to a new host easier. Oh, the bacteria also produces a complex molecule capable of killing insects that attempt to scavenge the corpse, allowing super easy transition into a new host.

These are very cool bacteria.

Pictured: Not a glow worm. This is the hollowed out carcass of Manduca sexta or the Tobacco hawkmoth larvae glowing due to the highly concentrated and numerous quantity of Photorhabdus luminescens

There’s always a human angle…

Okay, so maybe I wasn’t being entirely honest when I made a big deal about the expectations of these columns being about human diseases only. Turns out the bacteria have an interesting human angle that in fact was the first thing that attracted me to them. Whilst it is recognised as a human pathogen it is typically asymptomatic and is extremely rare with only 14 reported cases in medical literature. So it’s not a human disease that interests me.

What I find interesting is that Photorhabdus has been suggested as the cause of a mysterious phenomenon called ‘Angels glow’. If you were looking for a set of conditions in which Photorhabdus, an insect pathogen that normally lives in the soil, might be able to grow in a human you would need a few things. Open wounds, where soil etc might be able to access the body’s rich nutrient supply, a lot of exposure to soil, poor nutrition, inadequate medical treatment would all be required, and where would you find these conditions met? Trench warfare.

Some soldiers reported that their wounds glowed and reports taken at the time suggest glowing wound rarely got infected and the patients had a much better prognosis. The glow was seen as a gift from the angels thus ‘Angels glow’. It is widely believed that the glow was Photorhabdusluminescens growing in the wounds of soldiers. The wounds didn’t become infected due to all the nasty stuff spewed out by the bacteria that killed off potential disease causing pathogens allowing the wounds to heal normally. It is expected the bacteria would eventually be removed by the immune system but persist long enough to prevent the growth of any nasties. Whilst it is convenient to attribute the phenomenon known as the ‘Angel glow’ to Photorhabdus we don’t have any remaining data to link the two definitively, what we have however does put it forward as the leading explanation.

One more thing about this bacteria and it’s human connection. What does the bacteria and nematode feed on? Insects. Where are insects a problem? Agriculture. This particular pairing of Heterorhabditis and Photorhabdus is currently in use as a biopesticide in a number of countries (including Australia). As it is not a manufactured chemical and there is currently a demand for organic produce, it is expected that the biopesticide industry, where natural predators for insect pests are used instead of standard herbicides and insecticides, will flourish due to its promotion as a natural alternative.

References

Gerrad J. et al., (2003). “Photorhabdus Species: Bioluminescent Bacteria as Emerging Human Pathogens?” Emerging Infectious Disease V9 (2)

Waterfield N. et al., (2009). “Photorhabdus and a Host of Hosts” The Annual Review of Microbiology V63

…

Ants Eat Well, Thanks to Bacteria — Torrice 2009 1119: 2 — ScienceNOW.\

Posted by Jim:  Here’s another insect nitrogen story – leafcutter ants solve their low-N leaf problem by having N-fixing microbes in their gardens.  This reminds me of discussions I had with the late Professor Abe (Kyoto University) in 1997. Abe discovered that termites solve their N problem by harboring N-fixing bacteria in their guts.  I congratulated him on his terrific work and then asked him: ” So how do the termites get their phosphorus?”  Since his work was entirely focused on N, he didn’t really know.

Anyway, I think that in such cases the answer is usually “very slowly”.

I’d ask the same question of Torrice et al.: ‘Where do the leafcutters get their P?”  The answer is likely the same.  Rebecca Clark here at ASU is doing her PhD on the ES of leafcutter ants.  I hope she’ll have the answer!

…and the bugs are preparing to hibernate. Here’s a green shield bug – now in its dark brown winter colours

Wonderful sight

This was so great I was able to go to one inch up to this Spider that had made this awesome web between two Junipers in our backyard, every day we, the kids and I had a chance to see what this amazing Spider was up to.  Sometimes it was hiding in the Juniper waiting for some action.  This time it was I believe feeding on a bug.  It was interesting depends from what side I approached this Spider it would see me and move back to its hiding spot.  If I came toward it from his top it would not move so I can only think it did not see me and I was so happy to get these beautiful pictures so close up.

“Spider, Spider what do you see

Not me………

Come closer so I see you

Let me look at you ……ohhhh so beautiful what a delicate web

Just look, don’t touch,

 I will take care of you…..just look

I’ll be good to you”

By Jacqueline Grice

drowning. Got all these arms but they’re useless. Lack of oxygen and perspective brings you down. I guess the alienation gets you there to begin with…but…alienation and extra, but useless, limbs are probably one in the same.

Termite

Termites are small antlike insects that feed on wood.  Like ants, termites live in large colonies, in which there is a king and queen, many workers that build and tend the most and search for food and soldier termites that guard the next from insect enemies.

Termite nests are hidden in wood or in the ground.

Termites will eat nearly everything made of wood, including paper.  Those are live in the forests serve a useful function by cleaning away dead wood.  But when they attack our houses and belongings, that is a different story.

Oddly enough, the termite cannot digest the wood it oats.  The stomachs of termite workers are filled with little one-called creatures called protozoans.

The termite chews the wood and swallows the tiny chips.  The protozoans feed on the cellulose in the wood and convert it into foods that both the protozoans and the termite live on.

Visual source:  worldoftimepass

My friend Martyn from Texas had to count these in the fields for his degree. Thanks for the pictures Dr. Use the comment to take your guess and tomorrow I will tell you what it is.

Take a guess in the comment section below and thanks for playing name that bug…

Here’s the third photo I’ve posted of an insect.  (or insect shell in this case) We had a few cicadas here in Tennessee this year and I found this shell on a tree near my childrens’ school.  I usually like ‘pretty pictures’ but I thought this one was interesting and clear.

15 cicada broods have been identified by Scientist and are described using Roman numerals. Brood XIX, 13-year cicada distribution last emerged in Tennessee in May 1998.  Scientists project them to re-emerge in 2011.   This Brood was very large.  I remember not wanting to even go outside because it looked like an Egyptian Plague.  They were swarming and making noise that was almost deafening.  I remember going to the post office one day with my husband and I refused to get out of the car.  The cicadas were all over the place.  One lady was doing the ‘cicada dance’ from her car to the post office door screaming the whole way… No thank you. 

Now that most trees have lost their leaves, we find out what was hiding in their branches all summer long. Bird and squirrel nests are suddenly visible, and hornet nests turn out to be much more common than we ever imagined. I almost never see a Bald-faced Hornet in summer, but now I’m finding their nests in many trees in Columbus Park and throughout our Oak Park neighborhood. They look like big gray basketballs silhouetted against the sky:

Hornet nests look like big gray basketballs or balloons stuck in trees.

But when you get closer, you can see the arcs of hornet-made paper, glued by hornet “spit” to build the outer layers of the nest:

Hornets chew up dead wood, mixing it with saliva to make their own brand of paper.

Some brave creature tore off the bottom of this nest:

I'm hoping whoever tore into this nest waited until all the hornets were gone. (Worker hornets die off each fall, and next year's queen hornets burrow into soil or rotten logs to spend the winter in suspended animation.)

The outer layers of protective paper were torn away, exposing the inner cells — hexagonal tubes that look a bit like honeycomb:

Although the inside of a hornet nest looks like the honeycomb inside a bee hive, hornets build their entire nest with home-made paper (not beeswax).

Now, I’m not going to get all didactic and lecture you about the differences between honeybees and hornets. Let’s just say they both sting if you get too close, you’re not going to get much honey from a hornet, and honeybees won’t help control the fly population around your home. If you want to learn more, check out these online references:

• Who Are You calling a Bee, Mister?! Identifying Bees, Wasps, Hornets and Their Nests
• Wikipedia on Bald-faced Hornets
• Iowa State University on Baldfaced Hornets (I guess there’s more than one way to spell it.)
• Ohio State University Honey Bee Laboratory on Paper Wasps and Hornets
• Wikipedia on a bunch of other wasps that are also called hornets

—–

One of my Facebook friends had some advice for anyone who might consider bring a hornet nest inside for the winter. Patrick wrote, “I remember, as a kid, bringing one inside before the cold had done its deed to the hornets.” In other words, wait until there have been a couple of good hard freezes to kill off any remaining hornets (or other insects) inside the nest.

—–

P.S. Thanks to the Columbus Park walker who told me where to find the broken-open nest!

I enjoy following bugs/insects around and trying to take their picture. However, it can be very trying. Most of the time I end up with the following…

Yes. Bug butts. They drive me insane – but not in a good way.

Apparently, insects have an agenda of their own.

While busy with my last hour revision for my last paper the other day, I’ve got such a sweet visitor who keepd me company throughout the night, a gigantic moth. I am lucky that I manage to get few closed-up shots of it, here’s one of ‘em

302431     แมลงศัตรูไม้ป่าและวนผลิตภัณฑ์     Insect Pests of Forest Trees and Products

การจัดจํ าแนกแมลงศัตรูไม้ป่าและวนผลิตภัณฑ์ ความมากมายและความสํ าคัญประเภทและลักษณะการทํ าลาย ปัจจัยแวดล้อม การสํ ารวจแจงจับ การป้องกันและควบคุม ชนิดและชีวประวัติของแมลงศัตรูไม้ป่าและวนผลิตภัณฑ์ มีการศึกษานอกสถานที่

(Classification of insect pests of forest trees and forest products, abundance and importance, types and damages, environmental factors, inventory, prevention and control, species and life history of insect pests of forest trees and forest products. Field trip required.)

(302431 มหาวิทยาลัยเกษตรศาสตร์)

Bumblebee at Work

Though the common thistle is often regarded as a noxious weed, especially by those who prefer pasture to prairie, not all thistles are Eurasian invasives. A large percentage are true Wisconsin natives. They produce good nectar and so are especially attractive to butterflies, hummingbirds, and bumblebees.

I’ve been going through my summer photos, and found this busy bee. It is spectacularly a November day outside – breezy, chilly, partly cloudy – and the bee brought back pleasant memories of the many prairie strolls I took last summer.

I have managed to resurrect my blog at http://seededearth.com and will be posting there. You may think I’m a crazy woman, but no, I manage only to keep a half step ahead in this computer game. If you wish to follow me back to the “old place” I’d be most pleased.

I am walking to the train for my weekly salsa-lesson. The rain is falling, it is soft and beautiful.
I look up towards the streetlamp, lo and behold: a silly moth is playing suicidal games as it is zigzag flying in the rain.

I try to catch it, but no.

I suspect the moth will reach the light of its choice one way or the other.