Myrmecos

How ants acheive “balance”?

From an interview with E. O. Wilson:

[Q:]Are ants better at anything than humans?

[Wilson:] Human beings have not yet made an accommodation with the rest of life—whereas ants, whose history dates back more than 100 million years, have achieved that balance, mostly by specializing among the 14,000 known species in terms of where they live, what they eat, and how they relate to other species. Each, for the most part, has acquired a balance with prey, food, and space, halting population growth before it crashes. Ants have reached some degree of sustainability, while humans have not. We’re not going to last 100 years if we don’t start settling down.

Really?

I think the available evidence suggests the opposite.  Ants achieved their current dominance not through finding some magical ecological balance but by driving their competition to extinction.

Consider the ground beetles.  They are an older group of insects, occupying a similar soil/ground predatory role to many ant species.  But this ancient group of beetles is globally most abundant now only around the periphery of the ants, filling in the cracks that are too cold, too dark, too extreme for the Formicidae.  Ground beetles abound in boreal forests, along ice fields, in alpine meadows above the tree line.  What’s more, those that persist in the ant-rich tropics have a more potent defensive chemistry, as if those species that didn’t retreat in the face of the ant radiation stocked up on guns and ammunition.   We don’t know for certain, but the bits of evidence taken together it’s likely that the rise of the ants had a pretty significant effect on the ground beetles.  This nature is more Red in Tooth and Claw than singing Kumbaya in global harmony.

I understand Wilson’s angle-  that humans are destroying the ecological systems that sustain us- but surely that same point can be made without resting it on feel-good pablum without any empirical grounding.

Comments

  1. #1 EDenemark
    December 13, 2008

    Cool post, nice to see people not taking the words of famous scientists as ‘law’.

    I think your treatment of the Carabidae is a bit unfair though. The TOL page you linked us to claims 30,000 species with a fair diversity of lifestyles (some of which destroy entire ant colonies). Many more are probably waiting to be described.

    While I agree that ants aren’t the angels of conservation Wilson describes them as, and I’m sure they have taken their evolutionary toll on competitors, I really don’t think Carabidae have been shunned to areas where Formicidae simply can’t survive. These two families are almost always found in the same habitats. Cicindela larvae overlap with ants on a daily basis. I just can’t think of majority of habitats that are too extreme for ants…but not for Carabids.

  2. #2 jochenB
    December 13, 2008

    Ground beetles have definitely lost the “battle” in tropical forest: Few species in very low numbers. But try to find a square meter of tropical forest without ants.

  3. #3 EDenemark
    December 13, 2008

    Definitely a different story in African Savanna though, where many species of Carabidae overlap in habitat with an equal diversity of ants. Can we safely conclude the ants are the cause of Carabid absence in the tropical forest in light of their coexistence elsewhere?

  4. #4 Aydin
    December 14, 2008

    I think Wilson’s point is that unlike humans ants are not driving their prey or competitors into extinction. They may have pushed the ground beetles away, but there is still a balance between them & the beetles.

  5. #5 Emily
    December 15, 2008

    I think what’s more is that, while comforting, those feel-good conceptualizations of nature as a nurturing entity can actually be detrimental. When the objective of a conservation (or what have you) group is to change governmental policies or convince decision-makers to act based on facts, it can be harder to make truthful arguments if the minds in front of you have been prepared to receive what you’re saying via emotional sugar-coating. In worst-case scenarios, people may mistrust what conservationists say because it isn’t aligned with long-held beliefs. Real environmental stewardship is tricky, not least because the pressure to make concessions to human needs/wants means you gots to prioritize. Which means choosing which battles to sacrifice.

    Especially in urban settings, I think the tendency toward (young, well-intentioned) people is to fall into the trap of buying the Nature-as-nurturer world views. They seem to focus their resources on the minimally useful things they can do to help, instead of looking for the bigger picture.

    It’s a valid point that some high-visibility nature advocates promulgate ideas that are difficult to overcome, should they get in the way of making good stuff happen. Though I do get where Wilson is coming from.

  6. #6 James C. Trager
    December 18, 2008

    Down with pablum! But, I have to deal regularly in my “day job” with how to get the public, even those genuinely interested in them, to grasp the size and complexity of these issues.

    Regarding the ants & ground beetles question, it seems to me the two groups came early to exploit rather different parts of the prey base and have not been much in competition. The question might be whether their different ecological-evolutionary courses ultimately result from some sort of competition along the way or simply from distinct and stochastically not-very-interacting histories?

    The two groups do prey on one another, but, in the big picture hardly seem to be significant selective forces on each other. Are the mostly non-overlapping size ranges of carabid and ant predators in the Holarctic the result of competition over the course of evolution of the two groups, or are they the result of something else? Are relatively large-bodied predator ants abundant in the Neotropics because carabids are uncommon, or the other way around, or neither? Etc…..

  7. #7 barry goldman
    December 20, 2008

    what does the amber record suggest? does it go back to when carabids where abundant and ants not yet on the scene?

  8. #8 Eric R. Eaton
    December 22, 2008

    I’m left wondering (just a little) why Alex has such a beef with Dr. Wilson. This is not the first post taking a jab at Wilson, so while Alex makes an excellent point, I’m also sensing some underlying issues here….One thing no one is pointing out is that we humans are also animals, just like ants, and we behave in the same way as any other animal: we seek to eliminate mortality factors and competition, and increase our own population. The problem is, we can actually do it to a degree that ultimately backfires by undercutting the support structures of natural ecosystems. We need to acknowledge our “animalness” if we are to confront environmental issues. Aside, I also find it interesting that in urban society, largely a vacuum of nature, while we don’t have other species acting as our predators, parasites, and competition, we have murderers, con artists, and lots of competition….from our own species. I don’t think this is a coincidence.