In one scene a rufous woodpecker from India is shown breaking open an ant nest and then busily eating ants. It piqued [...]]]> This week we’ve been watching The Life of Birds DVD set narrated by Sir David Attenborough.  Have you ever seen the series? If you love nature you should, because it is so well done.

In one scene a rufous woodpecker from India is shown breaking open an ant nest and then busily eating ants. It piqued my curiosity, so I decided to see what else I could find out. Although I didn’t find the exact scene online to show you, I did find videos of rufous woodpeckers eating ants.

This first video is rather dark, but shows two young birds feeding on ants.

It appears that these woodpeckers from the Kerala region of India specialize on ants. Vishnudas (2008) cites an earlier worker from 1912 who found 2,600 ants in the stomach of a rufous woodpecker.

Although this video is shaky, it shows another woodpecker going after ants. (Makes you appreciate the quality of the footage from the Attenborough DVD.) It cuts away as the ants come rushing out of their nest.

It turns out that Rufous Woodpeckers, Micropternus brachyurus, not only use ants as their main food source, but also depend on Crematogaster ants for nesting sites. The birds work together to open up the carton nests of Crematogaster ants, and then build their own nests inside.

In his paper, Vishnudas also reports that several other species of birds follow the rufous woodpeckers and feed on the escaping ants when the rufous woodpeckers tear ant nests open.

In North America, there are woodpeckers specialize on ants, as well.

Northern flickers probably eat the most ants. They spend much of their time feeding on the ground around anthills. One flicker was found to have 5,000 ants in its stomach.

Doesn’t it look like the flicker is trying to dig out larvae and pupae rather than workers?

Pileated woodpeckers often cut slots into tree trunks or logs to get at carpenter ant nests inside. The woodpeckers will continue to return to the same opening over time, picking off ants that peer through the opening or that rush out to protect the nest.

It is fascinating to find out about these birds that are so dependent on ants for survival.

Have you seen any of the Attenborough series?

Reference:
Vishnudas, C. K. 2008. Crematogaster ants in shaded coffee plantations: a critical food source for Rufous Woodpecker Micropternus brachyurus and other forest birds. Indian Birds. 4:9-11. (Available from Google Docs as a free .pdf)

The DVD set:

The Life of Birds book by David Attenborough

After all, look at the jaws (mandibles) on the Eciton burchelli soldier. (Photograph by April Nobile / © AntWeb.org / CC-BY-SA-3.0, downloaded at Wikimedia) Appears fairly fierce.

So, are they really horrors?

When reading the recent review of the Antsbirds & Ovenbirds book, Ossein asked [...]]]> Are New World army ants the dangerous killers that movies and other media suggest?

After all, look at the jaws (mandibles) on the Eciton burchelli soldier. (Photograph by April Nobile / © AntWeb.org / CC-BY-SA-3.0, downloaded at Wikimedia) Appears fairly fierce.

So, are they really horrors?

When reading the recent review of the Antsbirds & Ovenbirds book, Ossein asked for more information about Skutch’s descriptions of the army ants. Alexander Skutch spent years in the tropical rainforests where he commonly encountered army ants. Did Skutch worry?

On page 21 of the book (link will take you directly to the page), Skutch writes of Ecition burchelli:

“These ants are not nearly as formidable as sensational accounts depict them. They specialize on invertebrate prey. Active vertebrates of all kinds readily avoid them, perhaps not without a few stings.”

He goes on to add that

Often I have continued to sit at my table and write, while army ants scurried over the floor around me and the ceiling above me.”

On page 24, Skutch makes the point that New World army ants don’t even eat dead vertebrates. He recalls a time when a dead bird fell in the path of the raiding army ants and another time a dead snake was left in the path of the ants. Both times the army ants did not consume the remains, even though they were actively foraging.

The antbirds that follow the army ants are in no danger. In this video, you can see an elusive bare-eyed antbird standing while ants run nearby. It seems more concerned about the camera than the ants.

Bottom line, when it comes to New World army ants, the fervor has been mostly hype.

Have you ever heard that villages in some areas welcome army ants into their homes for pest control? Does anyone have a primary source for to back this up?

Let’s take a look [...]]]> Have you ever heard a gardener comment, “Spurge plants always have ants,” and wondered if it was true? I admit searching ground spurge (Chamaesyce prostrata) for ants when I find the weeds, and I am often rewarded. Ants are attracted to spurge seeds (previous post), but is there more to the story?

Let’s take a look at a spurge with numerous ants milling around it. Most are Forelius.

The ants seem to be visiting the complex structures that pass for flowers in ground spurge.

In this photograph the ant on the right appears to be visiting the flower. But there is also an aphid on the same plant.

Yes, there are aphids on the plant.

The ants are also collecting honeydew from the aphids.

This leads to the question, how significant are the two sources of sweets? Ants are known to regularly visit the nectaries of the invasive weed, leafy spurge, but I wasn’t able to find out much about ground spurge.

Another question arises about whether ants might be capable of pollinating ground spurge. Ants are thought to pollinate certain low-growing plants with small flowers that are tight to the stem, and ground spurge certainly fits the bill.

Selleck, et al. 1962 reported that leafy spurge was pollinated by ants. After reading their evidence, however, it might be a shaky conclusion.

What is up with ants and spurge? Do ants visit spurge where you live? Do the ants gather nectar? Any evidence of pollination?

Reference:

Selleck, G.W.; Coupland, R.T.; Frankton, C.(1962). Leafy spurge in Saskatchewan. Ecological Monographs. 32:1-29. free .pdf.

You have probably heard all about the relationship of ants and peony flower buds.

Peonies (Paeonia sp.) are small perennial shrubs that produce large, lovely flowers in the spring.  The flower buds produce nectar via extrafloral nectaries, which attract ants. The ants chase off potential herbivores until the buds open. A simple story, [...]]]> From the photo archives:

You have probably heard all about the relationship of ants and peony flower buds.

Peonies (Paeonia sp.) are small perennial shrubs that produce large, lovely flowers in the spring.  The flower buds produce nectar via extrafloral nectaries, which attract ants. The ants chase off potential herbivores until the buds open. A simple story, yet an entire garden mythology has grown up around it. You can do an Internet search for “peony ants” and find a wealth of funny, and at times sad, myths.

But there may be another piece of the story that is rarely mentioned.

Do you know what this plant structure is? (Quit looking at the ant )

Since I already mentioned peonies, you can probably guess it is the fruit of a peony. Inside each of those three “pods” are rows of seeds completing development.

As this is not a bud, what is an ant doing there? Take a look at the next few photographs and see what you think.

Mandibles agape…

Do you see the fly?

Has anyone seen this before? Do you know if the extrafloral nectaries are still active? Are ants just poor botanists?

If you want to find out more, try:

B L Bentley. (1977). Extrafloral Nectaries and Protection by Pugnacious Bodyguards. Annual Review of Ecology and Systematics, Vol. 8: 407 -427.

At first glance a harvester ant mound looks a bit like a pile of rubble.

If you start to study the mound, [...]]]> Remember the post a few weeks back showing the snail shells in the harvester ant midden? Let’s take a little closer look at what kinds of objects harvester ants collect and put on their mounds.

At first glance a harvester ant mound looks a bit like a pile of rubble.

If you start to study the mound, however, you begin to notice that the pebbles are roughly the same size. Harvester ants (Genus Pogonomyrmex) are known to gather various objects and deposit them around their nest entrances. Harvester ants in the western United States often gather pebbles, among other things.

Fossils

if you are interested in harvester ants, you should pick up the fascinating article by Daniel Adams in Smithsonian Magazine from 1984.  Adams described how paleontologist John Hatcher discovered a terrific place to find tiny fossils, such as the teeth of mouse-sized mammals. In fact he went from finding an average of 2 per day to over 87 per day.  What was his secret? Hatcher discovered that harvester ants pick up ant-sized fossils and drop them on their mounds. Hatcher simply had the locate ant mounds and sort through the piles. Much of what is known about the mammals that lived during the time of dinosaurs is due to the diligent collecting behavior of harvester ants.

Paleontologists and archaeologists both still use mounds as a source of tiny fossils today. The University of Colorado Museum of Natural History has an exhibit honoring the contribution of the western harvester ant (Pogonomyrmex occidentalis), called Tiny Collectors: Harvester Ants. This page has a photograph of a mound and more information about how the fossils are collected.

Most of the finds are in Montana, the Dakotas, Wyoming, and Colorado. I’m not sure, but there might even be something in the mound from Arizona.

Can you spot it in the upper right hand corner? To me it looks a bit like a tooth.

Beads

In 2009, Schoville et al. distributed beads of various sizes and colors around harvester ant mounds at measured distances to investigate how far harvester ants move artificial material. They found ants would bring back beads from as far as 48 m away, but most were collected within 20 m of the main entrance. They were interested in how harvester ants moving artifacts potentially effects archaeological findings.

Charcoal

Deborah Gordon first studied deposits of charcoal in Pogonomyrmex badius middens in 1984. She established that the pieces of charcoal were not incidental, because if she removed the charcoal bits, the ants quickly began replacing them. She concluded that the charcoal probably marked the ants’ territories and deterred other ants.

Smith and Tschinkel re-visited what they called “non-food collection” by harvester ants. They evaluated mounds in Florida and found that pieces of charcoal were the most common objects, as Gordon had. They suggested that the objects reflect a significant amount of material, and that once again, the collecting behavior probably isn’t incidental. They found a slight increase in temperature in mounds with charcoal versus those without, but found no evidence other ant species avoided the pieces.

Snail Shells

It turns out that other people have also noticed snail shells on harvester ant mounds.

PÁLL-GERGELY and SÓLYMOS are malacologists working in Turkey who found that harvester ant mounds can be a significant source of taxonomic material, especially for more cryptic species of snails.

They noted that the ants tended to collect the smaller species of snails, and the juveniles of larger species. They did not observe the ants feeding on snails, but noticed some shells were cleaned out and some were not. They emphasized that harvest ants are known to collect and feed on seeds.

Some ants do eat snails. Mark Moffett has a photo of a Basiceros singularis worker feeding a tiny snail to its larvae. (You might have to scroll through a few photos to find it.) Do harvester ants do the same?

Conclusions:

The bottom line is that harvester ants have some interesting and unusual things on their mounds, and as of yet, we don’t have a very clear picture exactly why or how. In any case, we humans have found ways to use their activities to our benefit.

What unusual items have you found on a harvester ant mound?

References:

Adams, D.B. (1984). Fossil hunters best friend is an ant called pogo: paleontologists use insects to find
small bones. Smithsonian, 15: 99-104.

Gordon, D. M. (1984), The harvester ant (Pogonomyrmex badius) midden: refuse or boundary? Ecological Entomology, 9: 403–412.

PÁLL-GERGELY, B. and P. SÓLYMOS. (2009). Ants as shell collectors: notes on land snail shells found around ant nests. Malacologica Bohemoslovaca, 8:  14–18.

Schoville, B. J. Burris, L. E. and L. C. Todd. (2009).  Experimental Artifact Transport by Harvester Ants (Pogonomyrmex sp.): Implications for Patterns in the Archaeological Record Journal of Taphonomy, 7 (4):  285-303.

Smith C. R. and W. R. Tschinkel. (2005). Object Depots in the Genus Pogonomyrmex:  Exploring the “Who,” What, When, and Where. Journal of Insect Behavior, 18 (6):  859-879.

Smith C. R. and W. R. Tschinkel. (2007). The adaptive nature of non-food collection for the
Florida harvester ant, Pogonomyrmex badius. Ecological Entomology, 32:  105–112.

Take this chip, for example.

Someone had spilled some chips on the ground. Those ants are doing a terrific job of cleaning up the mess.

This is a kibble of dog food someone had tossed out at a highway rest stop.

Ants also clean up dead [...]]]> Many species of ants are scavengers. They pick up what others leave behind.

Take this chip, for example.

Someone had spilled some chips on the ground. Those ants are doing a terrific job of cleaning up the mess.

This is a kibble of dog food someone had tossed out at a highway rest stop.

Ants also clean up dead animals.

Here’s a dead cricket that fell on the sidewalk.

It won’t be long before it is processed and hidden away underground.

Imagine what our world would look like if these creatures didn’t clean up for us.

In 1960, the famous primatologist Jane Goodall recorded an amazing event. She observed a [...]]]> Once again, our post today is inspired by a book, in this case two children’s books about Jane Goodall and her research. I’m reviewed the books at Wrapped in Foil and wrote about Jane Goodall’s early scientific career at Growing With Science.

In 1960, the famous primatologist Jane Goodall recorded an amazing event. She observed a chimpanzee poke a blade of grass into a termite mound. The termites clamped themselves to the grass in an effort to protect their colony from the intruder. After a short time the chimp pulled the grass back out and ate the insects clinging to it. Goodall’s observations were the first recorded evidence of an animal other than a human using a tool.

But what does this have to do with ants? Since her discovery, Jane Goodall and many others have watched chimps eating ants as well. One way a chimpanzee gathers ants to eat is using sticks or pieces of grass to probe nests of ants. First a chimpanzee opens the nest a bit by digging with its hands. Then the chimp pokes a stick into the opening. The furious ants bite the offending stick in an effort to defend their colony. The chimp then draws the stick out loaded with ants. The chimp either shoves the stick directly into its mouth to eat the ants, or removes the ants with its hand and pops them into its mouth like popcorn. What a yummy snack!

The second way a chimpanzee gathers ants is to pluck a nest of weaver ants from a tree. Weaver ants form nests by tying leaves together with the silk produced by larval ants. Although weaver ants lack a stinger, they do have a painful bite. To avoid the bites of the ants, the chimp quickly runs from the tree with the nest and then crushes it on the ground, preventing any stray workers from biting. Once crushed, the chimp simply pulls the nest apart and eats the flattened ants at its leisure.

What about another African primate, the gorilla? At first many researchers thought gorillas were strictly vegetarian, but then evidence began to mount that they also enjoy munching on ants, very smelly evidence. It turns out that the best way to check what gorillas are eating is to find their feces or dung, and look at what is inside, including ant remains. The studies showed that some groups of gorillas ate quite a few ants during certain times of the year. Gorillas have also been observed and filmed eating ants. They don’t just consume the ants accidentally while eating plants. No one knows for sure why gorillas eat ants, but probably the same reasons other animals do, to obtain certain nutrients or possibly as a form of medicine.

Edit: I forgot I had this link to a video of a weaver ant nest (also called green ants).

Sound a bit far fetched? It turns out that when scientists scattered cat food along the banks of cane toad-infested ponds, the meat ants would come to the shore to pick it [...]]]> Researchers recently discovered a way to control cane toads, an introduced pest, in Australia:  put out cat food for the meat ants, Iridomyrmex reburrus.

Sound a bit far fetched? It turns out that when scientists scattered cat food along the banks of cane toad-infested ponds, the meat ants would come to the shore to pick it up. If they encounter young cane toads emerging from the water while foraging there, the meat ants attack. In fact, in the study area 98% of emerging toads were laid into by ants within two minutes of leaving the water.

You might wonder if desirable species of toads meet the same fate. It turns out that other kinds of toads evade meat ants at all costs. Only the cane toads freeze in position long enough to for the meat ants to overwhelm them with their tough jaws.

What’s so bad about cane toads? The cane toads were introduced into Australia in an effort to control another pest in sugar cane (thus the name). Soon is became evident that when carnivorous vertebrates – marsupials, lizards, snakes or crocodiles- tried to eat a cane toad, they would succumb to its toxins. With so many cane toads, the threat to wildlife is a very real one.

Is the idea of using ants to control pests a new one? No, certain ants have been used by humans to control pests for centuries. As far as is known, the ancient Chinese were the first to use ants to protect crops. As long as 1,700 years ago, farmers employed weaver ants to keep caterpillars, stink bugs and small rodents out of their valuable citrus orchards. Today weaver ants are used to control citrus pests in Northern Australia.

The colors of this meat ant specimen photographed by April Nobile (Copyright AntWeb.org, 2000-2009. Licensing: Attribution-ShareAlike 3.0 Creative Commons License, downloaded from Wikimedia) have faded somewhat. Check out the gorgeous iridescent gaster of photographs of Iridomyrmex reburrus at Myrmecos.net.

Now, I wonder if sprinkling cat food about will keep cats from sitting on my keyboard.

Reference:
Georgia Ward-Fear, Gregory P. Brown and Richard Shine. (2010). Using a native predator (the meat ant, Iridomyrmex reburrus) to reduce the abundance of an invasive species (the cane toad, Bufo marinus) in tropical Australia
Journal of Applied Ecology, early view at journal website.

It turns out that insects are part of the story, but probably not in the way that you might think.

This is one of the insect characters, the larva of a Heliconius butterfly. [...]]]> Any ideas what the yellow dots are on this Passiflora leaf? Are insects involved?

It turns out that insects are part of the story, but probably not in the way that you might think.

This is one of the insect characters, the larva of a Heliconius butterfly. The female butterfly lays yellow eggs on passion vine plants, mostly in the tropics. The larvae consume a great deal of the plant before pupating.

In Arizona, another species can wipe out passion vines.

This is the larva of the gulf fritillary butterfly, Agraulis vanillae.

Researchers have shown the yellow spots on the leaves are made by the plants as a defense against these butterflies. When the butterflies lay eggs, they avoid laying on plants where another female has already deposited eggs. The yellow spots mimic eggs and thus fool the butterflies into going elsewhere.

That is only part of the story, however, because the yellow spots serve another purpose. Those are nectaries, glands that produce nectar. The free source of food attracts ants, which in turn defend the plant against any butterfly larvae that do hatch.

I have to say that at first glance the plant fooled me too. Did it fool you? Did you think those were insect eggs?

The theme today for Life Photo Meme at Adventures of a Free Range Urban Primate blog is “honor an invertebrate.” Why not ants that protect plants?