CLOSED: Cacti Ant

Link to a thread on the Cacti and Succulents forum.
http://davesgarden.com/forums/t/725886/

Have you seen this site?

http://www.ruf.rice.edu/~bws/efns.html

I never heard of 'extrafloral nectaries' before I joined DG, but apparently some Cacti and their EFN's have some kind of poorly understood symbiotic relationships with ants.
That's a neat page, but it raises a lot more questions than it answers!

Hi Clay,

Very cool link! Except that it seems to suggest these ants are somehow beneficial. I agree that if they prey on aphids and other bugs that attack my cacti, that can't be a bad thing. Now I'm intrigued. Am I mistaking the bad guys for the good guys?

Interesting that Cacti, or any plant, would produce a secondary nectar source to attract insects that can actually protect rather than pollinate them. These nectar sources as described are isolated from the natural pollinators.

I learn something new about these plants every day.

So maybe the little ants I see are my saviors? Other undetected bugs are doing the real damage? On the other hand I'm pretty sure it's the ants piling their debris on top of my plants, what do you suppose is the purpose of that? Protection for the growing tip? Or just a place to put their debris. Do they decide to nest under severly infected plants because they have a great food source? Is their presence a sign I have a problem? Sorry for all the questions but I know nothing about bugs.

I find it fascinating that these ants will climb up the legs of a 30" table and infest (maybe the wrong word) something in a 4" pot. Pile their debris right at the growing tip of the plant. They have to make a considerable effort to do this.

If it's in defense of the plant. I'm all for it :-)

Dave

Somewhere in the article it says something about being beneficial 'on average', that it isn't always good for a single plant, but for the species as whole.... very complicated. There's a discussion about ants and cactus on garden web somewhere too, I didn't read that yet.

I haven't had time to read the whole article. And it's a little beyond my laymans understanding anyway.

Beneficial on average? My interpretation of that is: Sometimes good, sometimes not. So maybe I didn't overreact nuking the first detected infestation with Pyrethrin. After all it was a very rare and special plant they first showed up on. Again I don't like to use chemicals, but this freaked me out so bad I didn't feel the "Insecticidal Soap" was going to do the trick.

I'm a collector of cacti and succulents. I have over 700 species in my collection. That means lots of single plants. All with their special problems.

I've been in Arizona for 20 years and have always been astounded by the variety of insects that inhabit this place. Something I never expected of the desert. Lizards yes, bugs no. My first experience was with what's locally known as a "Palo Verde" beetle. A giant cockroach looking thing with nasty pincers crawling across my living room floor. I don't think I could have jumped up on the couch fast enough! Next I was in the kitchen one day barefoot and felt a very sticky web under the counters kickboard. Got under there with a flashlight and was face to face with the biggest, healthiest female black widow I had ever seen. I think I jumped up so high and quick I hit my head on the ceiling.

Surprisingly I accidently discovered the most effective "Insecticidal Soap" of the day. All I had at hand was a spray bottlle of Formula 409. One shot and the spider came out, did a backflip on the kitchen floor, went into convulsions and died. I started to wonder about what I was cleaning my kitchen counters with!

Now I'm discovering there are some insects that will actually mess with my collection of C&S?

Hmm, may be time to simply nuke the site from orbit.

Dave