What’s at the Desert Botanical Garden today?
Ants, of course!
What a perfect way to unwind from a stressful week.
Ants and Pine Tree Resin
On a recent camping trip near Payson, Arizona, I found ants in a pine tree. They seemed to be defending a crack in the tree filled with resin.
The area looked like this:
I was interested in what they were doing, because I have read/seen conflicting information about the effects of pine resins on ants.
For example, in Tom Eisner’s For Love of Insects, he gives anecdotal evidence that ants are repelled by pine resin. Scientists have reported that stingless bees cover their nests with plant resins in response to ant attacks, suggesting the resins repel ants. One of the components of certain plant resins, limonene, is touted as a natural insecticide effective against ants (limonene is also found in citrus fruit peels).
The ants I had observed didn’t seem to be repelled by the resin. They were walking all over it, and apparently had a nest nearby.
I had also seen the video, Ants: Nature’s Secret Power. In this section, wood ants are shown carrying resin back to their nest, at some cost to themselves. Take a look:
Experiments have shown that wood ants, Formica paralugubris, use pine resins as antibiotics, that is, as protection against pathogens.
Is this a case of one ant’s poison being another ant’s medicine? It seems likely that different species of ants would have different reactions to resins. Also, resins are not all identical. Some contain different terpenes, or higher levels of resin acids, which could change the level of repellency or antibiotic properties.
Seems like a relationship that needs further investigation. What do you think about ants and resins?
For further information:
Michel Chapuisat, Anne Oppliger, Pasqualina Magliano, and Philippe Christe. (2007). Wood ants use resin to protect themselves against pathogens. Proc. R. Soc. B. 274: 2013–2017.
Published online 29 May 2007
Paper is available online for free
Lisette Lenoir, Jan Bengtsson, and Tryggve Persson. (2003). Effects of conifer resin on soil fauna in potential wood-ant nest materials at different moisture levels. Pedobiologia. 47 (1): 19-25.
Sara Diana Leonhardt and Nico Blüthgen. (2009). A Sticky Affair: Resin Collection by Bornean Stingless Bees. Biotropica. 41 (6): 730 – 736.
Wildflower Cafe
Our family got to spend the weekend camping near Payson, AZ.
I found one small patch of flowers that had ants visiting every time I walked by.
It was the original “wildflower cafe.”
There were also thrips and small beetles.
A bunch of different buprestids were feasting.
Hairstreaks and blues were common.
But it was the little ants that stole my “heart.”
Ants Tending Oak Galls
Ants are commonly known to tend Homopterans, such as aphids, scales, etc.
But what is this ugly thing?
Obviously it is attractive to ants. (I know, the photos aren’t the greatest).
Here’s another kind.
Wow, that one is popular.
Any ideas?
The plants these structures are on are oaks (Quercus). I believe they are Emory Oaks, but please let me know if they aren’t.
The reddish-brown structures are galls caused by cynipid wasps. There are a number of species that cause galls on oak trees, in particular.
The galls of some species secrete a sweet substance that is attractive to ants.
This one is a bit puzzling because the presence of ants are thought to protect against predators and parasites, but what could attack a gall wasp hidden inside a gall? Wouldn’t that plant tissue disguise and protect it?
It turns out that there are parasites that can kill gall wasps. In fact, scientists have shown via exclusion tests (by preventing ants from reaching galls), that survivorship of certain gall wasps is significantly increased when tending ants are present.
Security, and the gall wasps don’t even have to supply the payment. Now that’s sweet.
T. F. SEIBERT (1993). A nectar-secreting gall wasp and ant mutualism: selection and counter-selection shaping gall wasp phenology, fecundity and persistence. Ecological Entomology. 18(3): 247-253.