Ant Behavior – Page 6 – Wild About Ants

January 19, 2015

Eye-catching Behavior in Leptogenys Ants

Okay, you’ve probably already seen these ant videos because they are making the rounds of social networks, but I thought they were worth sharing again.

Bees Unlimited shared this video of Leptogenys ants moving a millipede in Cambodia.

Aren’t those chains of workers surprising?

Here’s a closer view, where you can see the details of the workers better.

I’m surprised this millipede isn’t discharging, because it looks fresh. Maybe it already did.

Finally, here’s another video of the same behavior by a different author at Wimp.com.

Forget the Ant Class in Portal. I’m headed to Cambodia.:-)
What about you?

January 26, 2014

Solenopsis xyloni Stores Spurge Seeds

Last week I flipped over a rock about six inches square and found this:

Okay, it doesn’t look like much until you zoom in closer.

The grayish-mound is a solid mat of oval, wrinkly seeds. Apparently they had been gathered and stored by the Southern fire ants (Solenopsis xyloni) you see running around. The ants were in full defensive mode.

The seeds were both on the ground and on the underside of the rock, so there was quite a mass of them.

Seeing the seeds reminded me of an earlier time (above photograph) I had found a similar cache of seeds under a rock . At the time I didn’t know what plant they were from, but now I have figured it out.

These seeds are from a type of ground spurge, Chamaesyce prostrata. Another common name is sandmat. (See post about Southern fire ants and sandmat).

The University of Arizona has an illustration of the plant in their older weed manual under the name Groundfig Spurge, Euphorbia prostrata. See the seed labeled “d” in the illustration?

A quick search of the internet revealed the UC IPM website states “Weed seeds, particularly spurge, may attract the ants away from the bait…” This statement is referring to Southern fire ants in almond groves.

Seems like there might be something worth investigating going on here.

Have you ever seen Southern fire ants with seed caches? What kinds of seeds did you find in them?

January 10, 2014January 10, 2014

Taking the Sting Out of Ants

A year or so ago one of our local newspaper columnists, Clay Thompson, wrote that ants don’t have stingers (“If nothing else, I know I’m not Montini and ants can bite.” Arizona Republic, Jul. 4, 2012).

That got me to thinking that why there might be so much confusion about whether ants (and other arthropods) bite, sting, both or neither. Take for example Dr. Seuss, who was so confused that he drew bees with stingers on their head.

Let’s first take a look at what a stinger is.

A stinger is a part of the body in certain arthropods that is used to deliver venom into another organism. It is found at the end of the abdomen or metasoma. The stinger may be used for subduing prey and/or for defense. This type of stinger is found in only two groups of arthropods: insects of the order Hymenoptera (ants, bees, and wasps) and arachnids of the order Scorpiones (scorpions). In the Hymenoptera, the stinger is a modified egg-laying tube, so only the females can have one. In scorpions, both sexes have stingers.

(Photograph of Dinoponera australis by April Nobile / © AntWeb.org / CC-BY-SA-3.0)

Do ants have stingers? Part of the confusion may erupt because some kinds of ants, like the Dinoponera above, do have a stinger (seen protruding at end of metasoma), whereas other species of ants do not. Lacking a stinger does not mean that those ants are not defended. They may still bite (with their mandibles) and also may spray irritating defensive chemicals.

To make things even more confusing, some species of ants, the most infamous being the fire ants, bite and sting in a combined action. The irritated worker ant grabs the skin of the person with its mandibles, draws up a section to be targeted, and then curves its metasoma around and introduces the stinger. It is kind of an insulting double-whammy.

Here in Arizona, we have more that our share of prickly and stinging things, so I’m not sure why Clay Thompson miffed this one. Perhaps many people, including Clay, fail to find the exact method of delivery of pain of any importance and simply swat the offending insect away without identifying what happened to them. To them, bite or sting, the end results are the same.

What do you think?

See what other bloggers have to say:

Biting and Stinging: The Ants at 6Legs2Many

Why do only some ants sting? by Alex Wild at ScienceBlogs

Alex Wild also brings up the very good question: “Why do so many tropical ants sting, while those in Boreal latitudes never do?” at Myrmecos

Edit: And yet another reference to Alex Wild, Ouch! Insect Bites and Stings Up-Close (PHOTOS) at Weather.com

July 23, 2013

Rain Puts Ants – And Ant Fanatics – Into a Tizzy

Most of the time it doesn’t look like much is going on in the Sonoran desert during the day.

Of course, looks are deceiving, because there is often a lot going on that is subtle.

After a rain like we had this weekend, however, life comes bursting out.

We went for a hike at South Mountain Park on Sunday morning. Rain had fallen in the night, and as you can tell from these photographs, it was still cloudy. It was also extremely humid.

It is impossible to capture the level of activity in photographs, but ants were just streaming out of their nests. These are shiny black Messor pergandei.

Rain stimulates activity for at least two reasons.

First of all, the ants are scurrying to collect seeds.

Some desert plants release their seeds in response to rain. Also, the rain knocks down seeds that are higher up in trees and shrubs. That means there is a flush of new seeds to collect after a storm.

Most of you probably already know the second reason ants are hyper-active after a summer rain.

See if you can spot the reason in these photographs of a Pogonomyrmex rugosus nest entrance.

Did you spot the princess (alate)?

She went back inside this time, but I bet later in the afternoon the alates from this nest were swarming.

Wish I had all day to watch them and a HD video camera. Maybe someday soon…

Are the ants swarming where you live?