Category Archives: Natural History

This category includes observational field notes and reflections.

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.

 

Prairies in a Changing World: State of the Prairie Conference 2014

Conferene poster

The Native Prairies Association of Texas (and the Coastal Prairie Partnership) had their annual meeting in Fort Worth at the Fort Worth Botanical Garden from May 29 – May 31, 2014.  I was invited to present my research on ants in the prairies of the Fort Worth Nature Center in Fort Worth and the Southwest Nature Preserve in Arlington, Texas.

I also attended most of the meeting and gained a lot from the presentations I attended and especially from hobnobbing with other attendees.

**I want to pass on that Native American Seed is producing a seed mix especially to attract native bees which will be available this fall. Here’s the link to this Seed Source.

Here is the agenda for May 30 and May 31, following which I post my notes on the few talks I was able to attend with some comments and finally my presentation and extensive notes on the slides.

May 30 Agenda

State of the Prairie Agenda for May 30

May 31 Agenda

State of the Prairie Agenda for May 31

My Notes and Comments

State of the Prairie Conference Notes

Demonstration Prairie 5

The Demonstration Prairie at the Fort Worth Nature Center (photo above)

I presented my research on the ant species I have found in 17 sites at the Fort Worth Nature Center and what this means for 1) the possibility of using ants as bioindicators and 2) for the ecology of the Cross Timbers Ecoregion.

“Jills of All Trades: Ant Diversity and Flexibility in the Cross Timbers Ecoregion”

Here are my notes. In these notes I include quite a bit more than I was able to cover, in part, so that if you did not attend, you can follow the slides. If you have questions, message me.

Jills of all Trades_Presentation Notes

And finally, I mention a 10 minute digital recording I made of the Comanche harvester ant “remodeling” a ground bee nest that was too close to the ant nest. Here is a the video:

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):

Ants on Baits at the Fort Worth Nature Center

This is the demonstration prairie located in front of the Hardwicke Interpretative Center of the Fort Worth Nature Center in Fort Worth, Texas. The students set up some bait stations in this area.

This is the demonstration prairie located in front of the Hardwicke Interpretative Center of the Fort Worth Nature Center in Fort Worth, Texas. The students set up some bait stations in this area.

On April 29, 2014, sixth graders from Trinity Valley School (Ms. Julie Frey) in Fort Worth, Texas came to the Fort Worth Nature Center to learn about horned lizards and the ants they eat, mostly Pogonomyrmex ants, commonly called harvester ants because they mostly eat seeds. As part of their time with me, we set up tuna and pecan sandies cookie baits and made observations. At the conclusion, the students collected the ants for identification. I also recorded some video of the ants.

Although we attempted to set this up as a controlled study, it was a good preliminary investigation. The students explored their areas — limestone ridge, woods, or open prairie — and tried alternative ways of placing and using the baits. They did a good job of investigating.

I set them up with a data sheet to record location, weather, type of bait (tuna, cookie, or both), time of first arrival to the bait (and what this was), time for first ant arrival, observations (numbers of ants; rate of foraging, interactions, etc.), and how many ants on the baits after 5 minutes. (I did not get the data sheets so I cannot share that part.)

I recommend this kind of exercise for teaching about science method, forming hypotheses, investigating insects and foraging. It is easy to do and can be done anywhere. You can develop all kinds of ideas and possible experiments from this kind of work — myrmecologists do so all the time.

Here is a summary of the ants the students collected and some short clips from the video.

METHODS for Identification:

The students collected the ants from the baits and put the ants and bait into jars. In the Formanowicz lab at the University of Texas-Arlington, I separated the ants from the baits, rinsed them and placed them in 95% ethanol. They were identified to species using various on-line and published identification keys.

The lab bench: using a Nikon dissecting microscope with 40X magnification.

Lab bench for ant identification

Lab bench for ant identification

Sorting the ants from the baits

Sorting ants collected on tuna bait

Sorting ants collected on tuna bait

Some photos of the ants: Photos were taken using a dissecting microscope at 40X with a cell phone.

Camponotus americanus: This is a carpenter ant that nests in wood and is mostly found in woodland though they may wander into prairie. These ants are large, 1.5 cm.

Camponotus americanus collected from baits at the Fort Worth Nature Center.

Camponotus americanus collected from baits at the Fort Worth Nature Center.

Crematogaster sp.: Crematogaster is called an acrobatic ant because their gaster (part of the abdomen) is attached such that the ants can carry it above their heads — in a rather acrobatic posture.

Crematogaster

Dorymyrmex flavus: Ants in the genus Dorymyrmex are easily recognized by a cone shaped structure on the their dorsal surface (just before the gaster). Their common name is cone or pyramid ants. The cones differ in size and shape. These differences are used to identify species.

Forelius mccooki (above) and Dorymyrmex flavus (below)

Forelius mccooki (above) and Dorymyrmex flavus (below)

The red arrow indicates the cone or pyramid on Dorymyrmex. This structure is diagnostic for the genus.

The red arrow indicates the cone or pyramid on Dorymyrmex. This structure is diagnostic for the genus.

Forelius mccooki

Forelius

Solenopsis invicta: This is the invasive, red imported fire ant. Note the antennae have a two-part club at the end and altogether there are 10 segments on each antennae. These features are diagnostic for the genus.

Solenopsis invicta collected from baits in the Fort Worth Nature Center.

Solenopsis invicta collected from baits in the Fort Worth Nature Center.

RESULTS:

Sample # Species Count
1 Solenopsis invicta  3
2 Crematogaster cerasi 2
3 Crematogaster cerasi 2
Dorymyrmex flavus  1
Forelius mccooki 18
4 Forelius mccooki 18
5 Crematogaster lineolata 6
Forelius mccooki 16
6 Camponotus americanus 1
Solenopsis invicta 1
Unknown 1
7 Forelius mccooki 3
Solenopsis invicta 1
8 Forelius mccooki 47
9 Solenopsis xyloni 3
10 Forelius mccooki 89
11 Crematogaster lineolata 4
Forelius mccooki 1
12 Solenopsis invicta 1
13 Forelius mccooki 2

Video clip #1: “Bug and Ants”

This clip shows many Forelius ants on a tuna bait. An insect, perhaps a bug, lands on the bait and interacts with these ants, then leaves. It looks like the ants may be performing a cleaning service which has been suggested for Forelius ants in some situations.

Video clip #2: “Crematogaster Waggle”

This clip shows many Forelius ants on tuna bait. A Crematogaster forager is in the lower right hand side. As this forager leaves the bait, she waggles her gaster indicating that she is dispensing a pheromone.
Here are the two short clips from tuna baits that the Trinity Valley School of Fort Worth, Texas set out at the Fort Worth Nature Center.

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

 

Some natural history aspects of the nest structure of the Comanche harvester ant

In this poster, I summarize some natural history aspects of nest structure of the Comanche harvester ant (Pogonomyrmex comanche) which I have uncovered over the several years I have been tracking this ant in the Fort Worth Nature Center in Fort Worth and in the Southwest Nature Preserve in Arlington, Texas. I am currently working through some hard data with respect to these images.

Comanche de-alate Queens as foragers

I am collecting more ant samples using pitfall traps to increase the sample size and  the number of different habitats for my ant assemblage study (per the suggestion of one of my committee members). I added two areas from the Southwest Nature Preserve in Arlington, Texas. One site is a mixed soil prairie site where there is a population of the Comanche harvester ant of about 50 colonies. The other is the forested site immediately beside this prairie. I will also be adding two sites from the Tandy Hills in Fort Worth and several more from the Fort Worth Nature Center. Here is the beginning data from the Southwest Nature Preserve:

I set out the traps on September 5 and collected the sample on the 8th. Looks like I have a new Temnothorax species which I haven’t been able to identify yet. I also have a de-alate Comanche queen from the forest. She cannot have been starting a new colony since these ants mate in May and June. This collection confirms my earlier observation of de-alate Comanche queens remaining in their natal nests as foragers in another population.

So far in the prairie: Pogonomyrmex comanche Dorymyrmex (probably two species), Forelius, Pheidole, Nylanderia (two species, maybe three), Trachymyrmex, Temnothorax texanus, Solenopsis (fire ant), Solenopsis (thief ant), and Crematogaster.

In the woods: Aphaenogaster, Pheidole, Crematogaster, de-alate Pogonomyrmex comanche queen, and Temnothorax.

Still working on species identifications. Of course, now I get to redo all my ordination analyses.