The Ant Parasites of Konza Prairie

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Konza6s
A redbud blooms along the eastern border of Konza Prairie, April 2013.

The prairies of central North America are especially harsh environments. Half a continent removed from the buffering effect of oceans, temperatures in the plains soar in summer and crash in winter. Winds, and often fires, surge across the landscape. The prairie is not an easy place.

Prairie is also an environment I don’t spend much time exploring, in spite of my current situation living as I do at their eastern edge in Illinois. So I was pleased when the entomology students at Kansas State University invited me out for a seminar last month. I spent a morning at Konza Prairie on the advice of James Trager, who had an unorthodox way of persuading me:

I hope you’ll get a chance to spend some quality time at Konza Prairie, especially in any recently burned areas, and have some good anting weather. On the several occasions I’ve been there, I’ve gotten the impression that ant abundance and diversity are both oddly low there, and you will be there at a really good time of year to check on this. I have visited there only in the heat of (a very hot) summer and early fall, less propitious times for anting.

An oddly low ant diversity? 

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A lack of ants is hardly the way to sell an excursion to a myrmecologist, but visit Konza I did. I was aided in my search for ants by one particular aspect of the landscape. Konza is full of rocks.

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Rocks warm up in the sun, and in spring when ambient temperatures are still low, ants move their early season broods up under the stones to incubate. With cool air, sunshine, and lots and lots of rocks, I had the perfect conditions to disprove James’ thesis.

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A morning’s photography is not a proper scientific survey, of course, but I was left with three general impressions:

  1. Konza’s ants are, in fact, quite abundant in spring in recently burned areas. Take that, James!
  2. Konza’s ants are, as advertised, not very diverse. Ok, I’ll give James that.
  3. A surprising number of nests host parasites.
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Yep. Lots of ants. (Forelius pruinosus)

Here’s my rather depauperate Konza species list:

  • Camponotus pennsylvanicus
  • Formica pallidefulva
  • Lasius neoniger
  • Forelius pruinosus*
  • Hypoponera sp.*
  • Crematogaster lineolata*
  • Pheidole dentata
  • Aphaenogaster rudis
  • Aphaenogaster tennesseenis
  • Monomorium minimum
  • Solenopsis molesta*

Ants with a “*” were ones that showed up under rock, after rock, after rock, after rock.

(added in update) Commenter FormicidaeFantasy has formally surveyed the ants at Konza, finding 29 species total. That’s a great deal more that I uncovered in a few hours of searching, but still pretty low for a latitude in the high 30s.

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Monomorium minimum working at the nest entrance.

Nearly every Crematogaster lineolata nest- and I found dozens- hosted ant crickets.

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Myrmecophilus sp.
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Myrmecophilus sp.

In a colony of Solenopsis molesta thief ants I discovered the oddest little wingless diapriid parasite:

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Bruesopria sp. probably develops on the larvae of thief ants (thanks to Facebook’s Hymenopterists forum for helping narrow the identification of the wasp!)
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Bruesopria sp. in with the thief ants.

I already blogged this ant over at CE, but here is a queen of the temporary nest-founding parasite Aphaenogaster tennesseensis who has successfully infiltrated a nest of Aphaenogaster rudis:

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Aphaenogaster tennesseensis queens are highly attractive to their Aphaenogaster rudis hosts.

Finally, because a prairie has more than ants, or so I’m told, here’s a bee:

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A small sweat bee visits a dandelion.

13 thoughts on “The Ant Parasites of Konza Prairie”

  1. Sub-text question re ant diversity in prairies burnt and unburnt – was there an expectation diversity would be higher or lower in recently burnt areas?

    1. Prior to my recent collections/analysis on Konza, I predicted that it would be higher in some intermediate stage, as some level of fire is natural for the prairie (in other words, I assumed that very high fire frequency and strong fire suppression would both act as “disturbance” and decrease diversity). Contrary to my expectations, the final results indicate no trend of direct effects of fire on ant diversity – however, there is potentially an effect on diversity deriving from grazing and fire acting in concert.

  2. Hey, I’d still argue that the diversity isn’t as low as it seems. As I indicated earlier, I found around 29 species! But I guess it’s ok if my comments go unnoticed, like a Bruesopria sp. 😀

    Also, I can’t believe you got a Camponotus sp. – I didn’t get any with weeks of collecting. Lastly, your classification of the Aphaenogaster sp. might help my final species designations for the genus – for some reason I had issues finding consistent differentiating traits, and this may partially be because I started down the wrong track calling them the wrong things.

    1. formicidaefantasy — 2 spp. is close to 3X what Alex found, but you spent a good bit more time on your survey, of course. I’d like to see your list and annotations when you’re ready to share them.

  3. Cool, Alex! I’m glad I was able to stimulate this photo-expedition.
    I don’t know what the short and long-term effects of burning on prairie ants are — Perhaps a sort of intermediate disturbance effect as formicidaefantasy mentioned. I do know that the very finding of ants in prairies is much easier when the sites have been cleared of vegetation by burning (also by harvesting hay), and any temperate-zone myrmecologist knows spring is a great time to find whole ant colonies (and their guests) near the surface. I am a way-down-the-list coauthor on a paper coming out soon about ants/grazing/fire, and my feeling after being involved with that is there’s still more to be learned before we can generalize.
    As for Camponotus, I remember once walking across the KSU campus once at 10 pm when it was still 95F out, and C. pennsylvanicus & C. americanus were ZOOMING around on the walkways! I’d be quite surprised if a good search didn’t also turn up both of these and also C. nearcticus (on the riparian tree trunks) at Konza.
    A for the general diversity, I still find it most odd that eastern ants are as poorly represented as they are, and that Great Plains and/or southwestern elements are apparently non-existent there.

    1. Interesting.

      We did a small, yet unpublished, burn study on grasslands just west of Williams Lake (about 52 deg N), British Columbia, with a former student, Brock Harpur. Using pitfalls in these fairly cool grasslands we saw a strong increase in ant diversity with both moderate and heavy burns as compared to unburned. Our sense was that the heavy thatch was reducing insolation, and thus heat to the soil. Our numbers were lower, as you might expect. We collected 5 species in unburned sites and 9 in moderate and severe burns (1 yr post-burn).

      Regarding Camponotus, we have C. vicinus in the grasslands. It is commonly found nesting under rocks far from any source of woody debris.

      Rocks do hold heat in cooler climates and are commonly used by BC ants. Wood, despite the structural differences has similar thermal properties and when you get into really cool, wet soils in BC, almost all ants have shifted to wood. Thatched nests are another technique ants use to improve thermal conditions in the north.

  4. Matthew Sellner

    I enjoyed your article “Ants and their imposter mothers” and understand the process better. Is Aphaenogaster tennesseensis the only species of queen that acts as a parasite or is this common in other ant species?

    1. Surprisingly common, Matthew. All the citronella ants (Lasius (Acanthomyops)) nest-found this way, as do many Formica, Myrmica, Dorymyrmex, and a handful of others. Temporary nest-founding parasitism seems to be a common feature of north temperate/boreal ant faunas, and is much less common in the tropics.

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