Tag Archives: Pogonomyrmex comanche

The Spatial Ecology of the Comanche Harvester Ant

I have successfully presented my dissertation work and am currently finishing up the revisions for the final submission to the University of Texas at Arlington for the PhD degree. I expect the final dissertation to be available from the university library by July 2015.

The title of the dissertation is: The Spatial Ecology of the Comanche Harvester Ant, Pogonomyrmex comanche (Hymenoptera, Formicidae)

Dr. Esther Betran was the chair of my committee (UTA).

Other committee members were:

Dr. Jonathan Campbell (UTA)

Dr. Paul Chippindale (UTA)

Dr. Sophia Passy (UTA)

and Dr. Walter Tschinkel (FSU)

Here is the slide presentation and the notes which are numbered to correspond to the slides. I have included some of the corrections that came out of the discussion with my committee and otherwise have noted where there are other problems which I am addressing in the revision.

The slides:

and the notes:

Ants as Ecosystem Engineers

Comanche harvester ant (Pogonomyrmex comanche) nest year

Comanche harvester ant (Pogonomyrmex comanche) nest year

Many ant species are ecosystem engineers. An ecosystem engineer is an organism which structures the environment to suit its needs and in doing so has profound effects on the occurrence, abundance, and spatial pattern of other species. Beavers, who turn streams into ponds, are the textbook example. Ants do exactly the same thing in soil. They are soil engineers. Through their nesting habits, ants are agents of bioturbation, mixing soil horizons and creating avenues for water and gas exchange through the tunnels and chambers that make up their nest architecture. These activities result in soil production and altering soil chemical, physical, and biotic profiles.

nest casts

Their movement of materials from above and below ground concentrates nutrients and minerals in the nest and associated soil. The above ground nest structure is engineered as well. By creating soil or other mound structures, the ants may prevent plant colonization and change soil temperature and moisture profiles. The addition of pebbles to nest mounds done by Pogonomyrmex barbatus and P. rugosus, for instance, changes the temperature of the upper region of the nests. These species intentionally forage pebbles from the environment to do so. The parasitic, commensalist and mutualist organisms which may share these nests change the soil communities since these species would not be present at all without the ants.

Todd Island (TI-1) site at the Fort Worth Nature Center, Fort Worth, Texas. Note the Comanche harvester ant nest in the bare area, lower left.

Todd Island (TI-1) site at the Fort Worth Nature Center, Fort Worth, Texas. Note the Comanche harvester ant nest in the bare area, lower left.

Through all these activities ants engineer the soil to be suitable for the internal environment of their nests insuring the development of their young and their own survival. Because of this soil engineering, the occurrence, abundance, and spatial pattern of soil organisms and therefore the soil community are significantly different in areas with ant nests and those without. In turn, the differences in the soil community affect soil nutrient cycling and availability which affects these communities as well as the plant community which has a large portion of their bodies above ground. When an ant colony dies or moves, the nest area becomes available for colonization. As a result of the far reaching impacts of their engineering, ants have been used as indicators of ecosystem health and function, specifically tracking the progression through climax stages and in remediation of mining sites specifically due to soil production and engineering activities of ants.

The external nest of a Comanche harvester ant. The ants remove any plants from this nest yard area.

The external nest of a Comanche harvester ant. The ants remove any plants from this nest yard area.

Here I have focused mostly on the engineering of ground nesting ants on soil and provided photo of Pogonomyrmex comanche nests. Ant engineering may include many other ant species and other ecosystem impacts such as foraging activities including vegetation clearing on foraging areas and trails and foraging on seed and vegetative parts through which ants can impact plant populations and communities.

Because ants are central place animals, like beaver, their engineering is of local significance and contributes to the importance of spatial ecology for understanding ecosystem function and health.

 

Selected Literature

Andersen, A.N. 1990. The use of ant communities to evaluate change in Australian terrestrial ecosystems: a review and a recipe. Proceedings of the Ecological Society of Australia 16: 347 – 357.

Bucy, A. M. and Breed, M. D. 2006. Thermoregulatory trade-offs result from vegetation removal by a harvester ant. Ecological Entomology 31: 423 – 429.

Carlson, S. R. and Whitford, W. G. 1991. Ant mound influence on vegetation and soils in a semiarid mountain ecosystem. American Midland Naturalist 126: 125 – 139.

Cox, M. G. and Blanchard, G. B. 2000. Gaseous templates in ant nests. Journal of Theoretical Biology 204: 223 -238.

Dean, W. R. J., Milton, S. J., and Klotz, S. 1997. The role of ant nest-mounds in maintaining small-scale patchiness in dry grassland in Central Germany. Biodiversity and Conservation 6: 1293 – 1307.

de Bruyn, L. A. L. 1999. Ants as bioindicators of soil function in rural environments. Agriculture, Ecosystems, and Environment 74: 425 – 441.

Dostal, P., Brezniva, M., Kozlickova, V., Herben, T. and Hovar, P. 2005. Ant-induced soil modification and its effect on plant below-ground biomass. Pedobiologia 49: 127 – 137.

Eldridge, D. J. 1993. Effects on ants on sandy soils in semiarid eastern Australia: local distribution of nest entrances and their effect in the infiltration of water. Australian Journal of Soil Research 31: 509 – 518.

Elmes, G. W. 1991. Ant colonies and environmental disturbance. In: The Environmental Impact of Burrowing Animals and Animal Burrows [Symposium of the Zoological Society of London 63]. Clarendon Press: Oxford, UK. p. 15 – 32. Clarendon Press: Oxford, UK.

Folgarait, P. J. 1998. Ant biodiversity and its relationship to ecosystem functioning: a review. Biodiversity and Conservation 7: 1221 – 1244.

Hendricks, P. and Hendricks, L. M. 1999. Field observations on the myrmecophilous beetle Araeoschizus airmeti Tanner (Coleoptera: Tenebrionidae) at harvester ant mounds (Hymenoptera, Formicidae) mounds. Great Basin Naturalist 59: 297 – 299.

Lesica, P. and Kannowski, P. B. 1998. Ants create hummocks and alter structure and vegetation of a mountain fen. American Midland Naturalist 139: 58 – 68.

MacMahon, J. A., Mull, J. F., and Crist, T. O. 2000. Harvester ants (Pogonomyrmex spp.): their community and ecosystem influences. Annual Review of Ecology and Systematics 31: 265 – 291.

New, T. R. 2000. How useful are ant assemblages for monitoring habitat disturbance on grasslands in south eastern Australia. Journal of Insect Conservation 4: 153 – 159.

Nikem, J. N., Lobry de Bruyn, L. A., Grant, C. D., and Hulugalle, N. R. 2000. The impact of ant bioturbation and foraging activities on surrounding soil properties. Pedobiologia 44: 60 9 – 621.

Pisani, G. R. 2009. Use of an active ant nest as a hibernaculum by small snake species. Transactions of the Kansas Academy of Science 112: 113 – 118.

Ríos-Casanova, L. Valiente-Banuet, and A., Rico-Gray. 2006. Ant diversity and its relationship with vegetation and soil factors in an alluvial fan of the Techuacán Valley, Mexico. Acta Oecologica 29: 316 – 323.

Smith, C. C. 1940. Biotic and physiographic succession on abandoned eroded farmland. Ecological Monographs 10: 421 – 484.

Snyder, S. R. and Friese, C. F. 2001. A survey of arbuscular mycorrhizal fungus root inoculums associated with harvester ant nests (Pogonomyrmex occidentalis) across the western United States. Mycorrhiza 11: 163 – 165.

Trager, J. C. 1990. Restored prairie colonized by native prairie ants (Missouri, Illinois). Restoration and Management Notes 8: 104 – 105.

Underwood, E. C. and Fisher, B. L. 2006. The role of ants in conservation monitoring: if, when, and how. Biological Conservation 132: 166 – 182.

 

Comanche Harvester Ant Harvests Yucca Seeds

Despite not being recognized by the Parks and associated Friends of the Southwest Nature Preserve in Arlington, Texas (And I have brought this to their attention), the Comanche harvester ant (Pogonomyrmex comanche) is an important part of the ecology of the Glen Rose Yucca Prairie.

This is a small prairie with about 60 Comanche harvester ant colonies.

This is a small prairie with about 60 Comanche harvester ant colonies

There are about 60 colonies in this 4.43 ha meadow.Comanche is generalist seed predator and when the Yucca are releasing their seeds, the ants are harvesting them. I have seen some colonies with all foragers bringing Yucca seeds. So, the ants have the potential to impact the Yucca population.

This Comanche harvester ant is harvesting a Yucca seed in the Southwest Nature Preserve.

This Comanche harvester ant is harvesting a Yucca seed in the Southwest Nature Preserve.

Comanche in SWNP

 

Here is a Comanche nest in the Yucca Meadow: typically a cone shape with a central entrance — the soil is sandy.

Comanche harvester ant nest in the Yucca Meadow

There are many grass and forb plants which have seeds Comanche will forage. Here a forager is bringing back a snake cotton seed. Because of the many hairs on this seed, Comanche appears to use it like Velcro and sometimes collects other seeds with these hairs, thus bringing back more than one seed.

Comanche harvester ant collected  a snake cotton seed

Note the spread of her jaws or mandibles and how she has curled her body around toward the seed.

There are several Comanche nests in the trails at the Southwest Preserve as well. Some of these are quite a distance from the Yucca Meadow.

Comanche harvester ants congregating at their nest

Comanche harvester ants congregating at their nest

The above nest is near the meadow.

Comanche harvester ant nest in a trail

The above nest is in a trail far away from the Yucca meadow. None of the trail nests have as distinctive a crater form.

Finally, there is at least one Barbatus harvester ant colony in a trail at the Southwest Nature Preserve, not far from the Yucca Meadow. This colony has moved it locations a few times over the past 5 years.

Barbatus harvester ant colony

No Place Like Home: the Comanche Harvester Ant in the Cross Timbers

I had  a short paper published in the frist issue of Post Oak and Prairie Journal (January 2015). In this paper, I highlight some natural history work that did not make it into my dissertation on the Comanche harvester ant (Pogonomyrmex comanche). I plan to follow up on this work in the near future.

The paper is titled: No Place Like Home: the Comanche Harvester Ant in the Cross Timbers. (Notice that my photo of a Comanche harvester ant made the cover — such a great Cover Girl!)

The Cross Timbers Ecoregion occurs in Kansas, Oklahoma, Texas, and perhaps Arkansas, where the eastern forests grade into the drier western grasslands and desert. This region is characterized by a mosaic of oak forests and prairie — which is exactly the mosaic of habitats the Comanche harvester ant likes. I believe that the Comanche harvester ant is an important part of this ecosystem in part because they nest only in the prairie but forage into the woods, thereby connecting these different habitats. In the near future, I plan to investigate how Comanche and other ants play a role in this dynamic ecoregion.

 

The Comanche harvester ant in the Southwest Nature Preserve

There is a population of 60 colonies of the Comanche harvester ant (Pogonomyrmex comanche) in a small prairie in the Southwest Nature Preserve in Arlington, Texas. I have been studying this population for several years – mapping the colony nest locations, observing their foraging, and testing nestmate discrimination.

Last week I discovered 4 Comanche colonies not in this prairie but in some of the trails in the preserve. There are also two colonies in the trail that goes by the prairie, separated by a line of trees and grass. Of these new colonies, I believe 3 are 3-4 years old and the other is 1-2 years old. It looked as though something or someone had tried to dig into the second and forth of these nests. I examined the areas around all these colonies but the only colonies were actually in the trails.

Locations of Comanche harvester ant colonies in the Southwest Nature Preserve. Note the colonies in green were located this year and are isolated from the main population in red.

Locations of Comanche harvester ant colonies in the Southwest Nature Preserve. Note the colonies in green were located this year and are isolated from the main population in red.

The colonies are probably located in the trails where the soil was more exposed — so easier for a queen to discern that the soil is sandy, easier to dig in, and lacking in much leaf litter and humus. These ants also use the established trail to start out their foraging journeys — this species does not make much use of pheromone trails but relies on vision for orientation.

Their presence in the trails is a bit intriguing. These colonies are separated by 150 – 440 meters and by dense forest from the population I have been studying. I wonder how these queens made it to these locations, how these queens choose their nest sites and how/if these colonies are (or will be — they might not be mature colonies and so not produce alates yet) involved in a mating lek with the colonies in the prairie. The mating of Comanche has not been studied and I have only some observations which suggest that it is different in timing and occurrence from Johnson’s (2000 and 20001) speculation on this species.

There was a lot of foraging going on at the Preserve on Sunday, May 11, 2014. Here are two digital recordings and photos of the Comanche colonies.

Photos of the 4 Comanche nests found in trails. All of these nests were about 30 – 50 cm in a rough diameter (that is, they were not completely round).

First Colony:

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Second Colony:

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Close-ups of the two entrances for the second colony (Full photo above):

Close-up of one nest entrance for Comanche colony 2        Close-up of the other entrance of Comanche colony 2

Third Colony:

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Forth Colony:

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Comanche harvester ant (Pogonomyrmex comanche) colony in a trail at the Southwest Nature Preserve, Arlington, Texas

Here is a digital recording of some Comanche foragers (third colony) getting a scavenged bee into their nest, The little black ant that comes in at times is an acrobatic ant (Crematogaster). This recording is about 10 minutes.

Finally, here is a digital recording of pollinators and pollen eaters in a prickly pear blossom (about 1 minute):

Prelimary Work on the Comanche Harvester Ant Colony Distribution

Here are two posters which summarize preliminary work on the distribution of nests of the Comanche harvester ant  (Pogonomyrmex comanche) in the Fort Worth Nature Center, Fort Worth Texas. The nests were located visually by walking through the habitat and locating nests and following foragers back to nests. Nests were then flagged and GIS coordinates recorded. Environmental variables, geospatial data, and co-occurring ant species (Forelius and Trachymyrmex turrifex) were also evaluated.

I am currently working through 5 years of this kind of data for my final dissertation project. In the  final project, I also have nest locations for a population in the Southwest Nature Preserve in Arlington, Texas.

From 2010: Nest Distribution of the Comanche Harvester Ant

 

From 2012: Tracking the Comanche Harvester Ant