Category Archives: Ant Assemblages

This category includes the assessment of the ant assemblages in 20 areas of the Fort Worth Nature Center, Fort Worth, Texas, two areas of the Southwest Nature Preserve in Arlington, Texas, and two areas in Tandy Hills Natural Area in Fort Worth, Texas.

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:

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:

Ant Presence and Abundance in the Fort Worth Nature Center

I sampled ants using pitfall traps in 17 sites in the Fort Worth Nature Center monthly in June, July, and August 2012.

I used CANOCO to run redundancy analyses (RDA) on ant presence with abiotic and biotic environmental variables and on ant presence and abundance with soil type to look for ant preference for soil. I used forward selection of variables and Monte Carlo significance tests to select the variables for the final RDA models.

RESULTS

1) RDA for ant presence and environmental variables

RDA Summary Table

Axes

1

2

3

4

Total variance

 Eigenvalues                     

0.122

0.062

0.026

0.014

1.000

Species-environment correlations

0.820

0.872

0.672

0.582

Cumulative percentage variance of species data

12.2

18.4

21.0

22.4

Cumulative percentage variance of species-environment relation 

51.5

77.6

88.8

94.5

Sum of all eigenvalues     

1.000

Sum of all canonical eigenvalues     

0.237

Triplot

2) RDA for ant presence and soil type

RDA Summary Table

Axes                                    1      2      3      4 Total variance
Eigenvalues

0.076

0.023

0.011

0.007

1.000

Species-environment correlations 

0.788

0.603

0.424

0.417

Cumulative percentage variance    of species data

7.6

9.9

11.0

11.7

Cumulative percentage variance    of species-environment relation 65.2   84.9   93.8 100.0
Sum of all eigenvalues

1.000

Sum of all canonical eigenvalues

0.117

Triplot

3) RDA for ant abundance and soil type

RDA Summary Table

Axes                                    1      2      3      4 Total variance
Eigenvalues

0.070

0.031

0.016

0.003

1.000

Species-environment correlations 

0.777

0.655

0.456

0.265

Cumulative percentage variance    of species data

7.0

10.1

11.7

12.0

Cumulative percentage variance    of species-environment relation

58.4

84.6

97.9

100.0

Sum of all eigenvalues

1.000

Sum of all canonical eigenvalues

0.120

Triplot

24% of species presence is explained by the environmental variables with percent litter cover and drainage being the significant variables. Sampling sites by date clumped together indicating a lack of seasonality — which seems a bit unusual since late July and August become quite hot and ant activity seems reduced  at this time.

12% of species presence was explained by soil type with the Aquilla soil being the only significant soil. This soil is the only soil type where the Comanche harvester ant (Pogonomyrmex comanche) is found. All other species are more generalist with respect to soil type.

7.4% of species abundance was explained by soil type again with the Aquilla soil being the only significant soil. This result further supports the result with species presence: only the Comanche harvester ant has such narrow soil preference.

CONCLUSIONS

Though the eigenvalues are low this is not unusual for ecological data. The low level of explanatory value of these variables is likely due to the generalist nature of these species (and more temperate species in general) and the below-ground nesting of most ant species.

The Comanche harvester ant (Pogonomyrmex comanche) was the only species to show strict preference for soil type. Exactly what this species’ preference or requirement is remains unresolved.

Redundancy Analysis on Ant Assemblage Data

Here are the preliminary results of the first redundancy analysis (RDA) for all the sites sampled over the summer of 2012. I performed a PCA with only environmental variables and one with only species data to look for an underlying pattern — which was confirmed. Then I ran an RDA with the full set of environmental variables and species data to determine the most significant quantitative environmental variables. Here are the results of the final RDA for this set of data which includes samples from 21 sites sampled monthly over the summer.

The Summary Table:

Axes

1

2

3

4

Total variance

Eigenvalues

0.358

0.129

0.060

0.020

1.000

Species-environment correlations 

0.977

0.956

0.923

0.720

Cumulative percentage variance of species data               

35.8

48.8

54.7

56.8

Cumulative percentage variance of species-environment relation

61.8

84.1

94.4

97.9

Sum of all eigenvalues     

1.000

Sum of all canonical eigenvalues     

0.580

Marginal effects of environmental variables:

Marginal Effects

Variable Var. N Lambda1
LiC 2 0.32
BG 4 0.27
LA 6 0.21
ToC 3 0.17
SP 5 0.07

Conditional effects of environmental variables:

Conditional Effects

Variable

Var. N

Lambda A

P

F

LiC 2 0.32 0.002 25.00
LA 6 0.13 0.002 12.20
BG 4 0.07 0.002 7.90
ToC 3 0.04 0.002 4.68
SP 5 0.02 0.028 1.81
LiC 2 0.32 0.002 25.00

Ordination Plots:

Species and environmental variables:

Species and Sites:

2013 America’s Grasslands Conference Proceedings

This past summer, August 12-14, 2013, the National Wildlife Federation and Kansas State University teamed up to have the 2nd America’s Grassland Conference in Manhattan, Kansas. I attended this conference and presented some preliminary work on some ant assemblages in the Fort Worth Nature Center, Fort Worth, Texas. I am completing that project this spring as part of my dissertation.

The proceedings from the conference, America’s Grasslands: The Future of Grasslands in a Changing Landscape, is now available. A summary of my preliminary  work is found on page 41.

The conference was wonderful. I have several posts concerning this conference:

1) the 2013 America’s Grassland Conference: Synopsis and Notes

2) Flint Hills, Tallgrass Prairie, Chase State Fishing Lake and the Gallery at Pioneer Bluff Field Trip

3) Konza Prairie Biological Station

Environmental Variable PCA Results

Here are the results from PCA on all environmental variables measured with descriptive (dummy) variables used as supplementary. The analysis was run in CANOCO and generated the following ordination diagrams and summary tables. This is an initial analysis. (Sites are identified by number, measured variables are smaller text and thin blue arrows, and supplementary variables which are not used to construct the ordination axes are larger blue text with gray arrows.)

For all 21 sites and all dates sampled over summer 2011:

PCA Summary for ALL samples, sites, and dates
Axes 1 2 3 4 Total variance
Eigenvalues

0.597

0.207

0.087

0.059

1.000

Cumulative percentage variance of species data               

59.7

80.4

89.1

95.0

Sum of all eigenvalues     

1.000

 

Environmental variables from 21 sites in Fort Worth and Arlington, Texas from the whole summer

Environmental variables from 21 sites in Fort Worth and Arlington, Texas from the whole summer

For all 21sites sampled in August 2011:

PCA Summary for SUMMER samples, sites, and dates
Axes

1

2

3

4

Total variance

Eigenvalues

0.620

0.226

0.067

0.047

1.000

Cumulative percentage variance of species data

62.0

84.6

91.3

95.9

Sum of all eigenvalues

1.000

PCA diagram for the environmental variables of 21 sites in Fort Worth and Arlington, Texas

PCA diagram for the environmental variables of 21 sites in Fort Worth and Arlington, Texas

For all 17 sites and all dates sampled in the FWNC over the summer 2011:

PCA Summary for ALL FWNC samples, sites, and dates
Axes

1

2

3

4

Total variance

Eigenvalues

0.590

0.183

0.112

0.035

1.000

Cumulative percentage variance of species data               

59.0

77.3

88.5

92.1

Sum of all eigenvalues     

1.000

Environmental variables from 17 sites in the Fort Worth Nature Center, Fort Worth, Texas over the whole summer

Environmental variables from 17 sites in the Fort Worth Nature Center, Fort Worth, Texas over the whole summer

Compiled for all 17 sites sampled over the summer 2011 in the FWNC:

PCA Summary for Averaged FWNC samples, sites, and dates
Axes

1

2

3

4

Total variance

Eigenvalues

0.594

0.198

0.119

0.035

1.000

Cumulative percentage variance of species data

59.4

79.2

91.0

94.5

Sum of all eigenvalues

1.000

 

Environmental Variables PCA from 17 sites in the Fort Worth Nature Center, Fort Worth, Texas

Environmental Variables PCA from 17 sites in the Fort Worth Nature Center, Fort Worth, Texas

 

 

Stratford and Tandy Hills Prairie Ants

I am completing the ant identifications for the prairie and forest in the Southwest Nature Preserve in Arlington, Texas and the additional prairies, Statford  and Tandy Hills, in Fort Worth, Texas. I believe I have found another Temnothorax species which I have not been able to identify and another Pheidole species. This is quite exciting. No Pogonomyrmex ants are found in the Stratford or Tandy Hills Prairies.

This is a sandy soiled prairie in the Southwest Nature Preserve in Arlington, TX. The Comanche harvester ant, Pogonomyrmex comanche, has about 50 active colonies in this area.

Preliminary Identifications for the SWNP – prairie ants

Here is a list of the ant species, tentatively identified for the Southwest Nature Preserve, Arlington, Texas — from the prairie site where the Comanche harvester ant is nesting.

Crematogaster lineolata

Dorymyrmex flavus and D. sp.

Forelius mccooki

Nylanderia arenivaga and N. vividula

Pheidole sp. (only minors)

Pogonomyrmex comanche

Solenopsis xyloni and Solenopsis sp. (Diplorthoptrum group, thief ants)

Trachymyrmex turrifex

 

Preliminary Ant Ids for the Southwest Nature Preserve

I have worked through the woodland sample from the Southwestern Nature Preserve, Arlington, Texas. Not many ants were in this sample, possible due to the continued heat.

I found

Crematogaster lineolata (acrobatic ants)

Aphaenogaster carolinesis  (I am pretty sure)

Pheidole – no species id yet (new to me) (big headed ants — definite majors and minors)

Temnothorax — not species Id yet (new to me; perhaps new find for Texas)

and one Pogonomyrmex comanche de-alate queen who may have been working as a forager for her natal colony (too late for her to be a newly mated queen). (the Comanche harvester ant)

 

The prairie sample has a lot more ants in it — which I found a bit surprising since it is so hot (still) now. I had thought the shade of the woodland would have allowed more species to remain active and the prairie ants would be on siesta. The traps are set out for several days in order to catch the ants whenever they are active.

Tandy Hills Prairie, Fort Worth, Texas

Addtional Sampling for Ant Assemblages

One of my committee members suggested I get more samples for my ant assemblage project. I have added three prairie sites and one woodland.

One prairie and one woodland site are in the Southwest Nature Preserve in Arlington, Texas. The Comanche harvester ant is nesting in this prairie. There are about 50 colonies of Pogonomyrmex comanche. Soil here is mixed but very sandy with some bare ground.  Currently working through these samples.

Prairie Site at the Southwest Nature Preserve, Arlington, Texas

Prairie Site at the Southwest Nature Preserve, Arlington, Texas

The woodland site at the Southwest Nature Preserve, Arlington, Texas

The woodland site at the Southwest Nature Preserve, Arlington, Texas

Today I set pitfall traps in the Tandy Hills Prairie and Stratford Prairie in Fort Worth, Texas. Comanche is not found in these sites. The soil here is dark and rocky, more clay and little sand, and no bare ground. I will collect these samples on Tuesday and see what I’ve got.

Tandy Hills Prairie Site, Fort Worth, Texas

Tandy Hills Prairie Site, Fort Worth, Texas

Stratford Prairie Site, Fort Worth, Texas

Stratford Prairie Site, Fort Worth, Texas