Images of Pogonomyrmex salinus - at various locations in Nevada, Oregon, and Washington states, USA.
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Scroll down PAST BOTTOM OF PAGE for complete image description, and CLICK large image to make it even LARGER...
***There may be multiple image pages; use red page/image controls below to see them all!***
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 1 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-tgc59tW/0/Ti/3317_10_7Df-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 1 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 2 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-TdRXr2H/0/Ti/3319_10_7Dc-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 2 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 3 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-V4nsdjZ/0/Ti/3322_10_7Dc-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 3 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 4 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-kFLdC7q/0/Ti/3324_10_7Dc-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 10:14AM sunny, air temp: 16°C / 61°F
[IMAGE 4 of 4] The seeds of western tansy-mustard (Descurainia sp.) are apparently a very important source of food for the Pogonomyrmex salinus ants of central Washington state. This series of four images was captured in the space of less than one minute - as a determined worker removed a relatively huge seed-pod from a living plant near her nest. Using her legs and gaster (large abdominal body part) to maximize leverage, she can be seen cutting through the stem, just below the seed-pod (1st and 2nd images). Suddenly, the pod is cut free, and the ant climbs out to the end of a seed-pod below, with cargo firmly held in her mandibles (3rd and 4th images). Two seconds after the last image, she dropped to the ground (from a height of about 25 cm / 10 inches) and ran at full speed to the nest, disappearing into the entrance with her prize.
ADDITIONAL NOTES/REFERENCES:
Descurainia (tansy-mustard) species thrive in dry (and often disturbed) soils, and are quite abundant in many areas where Pogos live. Nest middens are often full of empty Descurainia seed pods. We have observed and imaged P.salinus workers interacting with these plants in several locations in Washington state. These interactions encompass a range of behaviors, including the foraging of seeds/seed pods, removal of empty seed pods from nests, and the removal of entire plants from nest mounds and adjacent areas. Pogonomyrmex salinus has also been observed to collect the seeds/seed pods of various Descurainia species in Oregon and Idaho, and one study indicates that in central Oregon, Descurainia pinnata (western tansy-mustard) is one of the 5 most frequently collected seeds by P. salinus. The others were: Bromus tectorum, Phacelia linearis, Hordeum jubatum, and Sisymbrium altissimum.
·Jorgensen C.D. & Porter, S.D. 1982. Foraging Behavior of Pogonomyrmex owyheei in Southest Idaho. Environmental Entomology, Vol. 11, No. 2, April 1982
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● Horse Ridge area, SE of Bend [Deschutes Co], OR USA [el. 1310 m / 4297 ft] view location in Google Maps »
● 7/20/09 7:42AM sunny, air temp: 12°C / 54°F
At two separate locations in Oregon, we have observed Pogonomyrmex salinus workers transporting (or working on in some way) Juniper (Juniperus occidentalis) 'berries' . This ant was in the process of cutting away the outer covering of one, and a seed can be seen inside (a variety of haphazard cutting techniques were employed). This worker apparently lost interest, and walked away shortly after this image was captured. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
Juniper 'berries' are really highly modified seed cones, with fused, fleshy scales. We saw these objects on the ground in every state of ripeness and decomposition (at this location and one another in central Oregon). The color ranged from almost black to bright orange - sometimes with a white powdery coating, as in this image. The differences in color and texture presumably are a function of how long the berries had been lying on the ground. The ants did not seem to have a preference, and were seen retrieving ones that were in some cases, highly decomposed. We observed 2 of these objects actually being taken into a nest.
This is the only Pogo we have seen actually cutting open a Juniper berry, the others were being transported whole.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-kVdQCLC/0/Ti/0570_09_40f-Ti.jpg "pogolumina > ● Horse Ridge area, SE of Bend [Deschutes Co], OR USA [el. 1310 m / 4297 ft] view location in Google Maps »
● 7/20/09 7:42AM sunny, air temp: 12°C / 54°F
At two separate locations in Oregon, we have observed Pogonomyrmex salinus workers transporting (or working on in some way) Juniper (Juniperus occidentalis) 'berries' . This ant was in the process of cutting away the outer covering of one, and a seed can be seen inside (a variety of haphazard cutting techniques were employed). This worker apparently lost interest, and walked away shortly after this image was captured. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
Juniper 'berries' are really highly modified seed cones, with fused, fleshy scales. We saw these objects on the ground in every state of ripeness and decomposition (at this location and one another in central Oregon). The color ranged from almost black to bright orange - sometimes with a white powdery coating, as in this image. The differences in color and texture presumably are a function of how long the berries had been lying on the ground. The ants did not seem to have a preference, and were seen retrieving ones that were in some cases, highly decomposed. We observed 2 of these objects actually being taken into a nest.
This is the only Pogo we have seen actually cutting open a Juniper berry, the others were being transported whole.")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co] WA, USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/17/09 11:04AM sun, air temp: 22°C / 71°F
[IMAGE 1 of 2] With her powerful mandibles, a P.salinus worker cuts through the tube-like leaf of 'Indian rice grass' (Achnatherum hymenoides), uncovering the not-yet-emerged inflorescence, with its many tiny flowers (florets), and seeds.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-vBwtkSd/0/Ti/2369_09_Rf-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co] WA, USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/17/09 11:04AM sun, air temp: 22°C / 71°F
[IMAGE 1 of 2] With her powerful mandibles, a P.salinus worker cuts through the tube-like leaf of 'Indian rice grass' (Achnatherum hymenoides), uncovering the not-yet-emerged inflorescence, with its many tiny flowers (florets), and seeds.")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/17/09 11:06AM sunny, air temp: 22°C / 71°F
[IMAGE 2 of 2] 'Indian rice grass' (Achnatherum hymenoides) and P. salinus worker - 2 minutes and 13 seconds after the previous image. The ant has gained access to one of the florets (which contains the nutritious seed), and is continuing to free it from the stem. Less than 2 minutes later, she snipped the skinny pedicel (seen at the bottom of this image), and the whole floret dropped to the ground. This ant stayed on the plant, and continued working - leaving the retrieval of this potential food item to her nestmates on the ground. This large clump of grass was approx. .5 m / 2 ft from the nest entrance, but this appeared to be foraging activity only, and not an attempt by the ants to remove the plant.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-s5FR5tm/0/Ti/2375_09_Rf-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/17/09 11:06AM sunny, air temp: 22°C / 71°F
[IMAGE 2 of 2] 'Indian rice grass' (Achnatherum hymenoides) and P. salinus worker - 2 minutes and 13 seconds after the previous image. The ant has gained access to one of the florets (which contains the nutritious seed), and is continuing to free it from the stem. Less than 2 minutes later, she snipped the skinny pedicel (seen at the bottom of this image), and the whole floret dropped to the ground. This ant stayed on the plant, and continued working - leaving the retrieval of this potential food item to her nestmates on the ground. This large clump of grass was approx. .5 m / 2 ft from the nest entrance, but this appeared to be foraging activity only, and not an attempt by the ants to remove the plant.")
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m/500 ft] view location in Google Maps »
● 5/17/09 7:16AM sunny, air temp: 16°C / 61°F
Looking at this P.salinus worker from above, it is easy to see the subquadrate or 'squarish' head shape that is characteristic of these ants. The distinctive surface sculpure is also very apparent in this image.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-mVmRzCf/0/Ti/2157_09_Rf-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m/500 ft] view location in Google Maps »
● 5/17/09 7:16AM sunny, air temp: 16°C / 61°F
Looking at this P.salinus worker from above, it is easy to see the subquadrate or 'squarish' head shape that is characteristic of these ants. The distinctive surface sculpure is also very apparent in this image.")
![pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 12:15PM sunny, air temp: [not measured]
Silhouetted against the background, this P. salinus worker searches a plant for nectar in central Washington state.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-TJ7WxTt/0/Ti/3360_10_7Df-Ti.jpg "pogolumina > ● NW of Mattawa [Grant Co], WA USA [el. 152 m / 500 ft] view location in Google Maps »
● 5/9/10 12:15PM sunny, air temp: [not measured]
Silhouetted against the background, this P. salinus worker searches a plant for nectar in central Washington state.")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 12:17PM sun, haze, air temp: 25°C / 77°F
[IMAGE 2 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-cTb5h2D/1/Ti/2905_10_7Dc-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 12:17PM sun, haze, air temp: 25°C / 77°F
[IMAGE 2 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities \"...primarily due to the predominance of Bromus tectorum in the semi-desert areas.\" He also notes that \"the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively.\"
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that \"Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas.\"
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 12:31PM sun, haze, air temp: 25°C / 77°F
[IMAGE 3 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-MFL3vkP/1/Ti/2943_10_7Df-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 12:31PM sun, haze, air temp: 25°C / 77°F
[IMAGE 3 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities \"...primarily due to the predominance of Bromus tectorum in the semi-desert areas.\" He also notes that \"the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively.\"
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that \"Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas.\"
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-rVKMsGp/0/Ti/3005_10_7Dc-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities \"...primarily due to the predominance of Bromus tectorum in the semi-desert areas.\" He also notes that \"the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively.\"
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that \"Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas.\"
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 11:01AM sun, haze, air temp: 22°C / 72°F
[IMAGE 1 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-3DZzzrz/0/Ti/2860_10_7Df-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 11:01AM sun, haze, air temp: 22°C / 72°F
[IMAGE 1 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities \"...primarily due to the predominance of Bromus tectorum in the semi-desert areas.\" He also notes that \"the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively.\"
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that \"Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas.\"
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/16/10 9:00AM partly cloudy, air temp: 23°C / 73°F
[IMAGE 1 of 6] Winter rains had apparently washed away most of the external nest mound of this Pogonomyrmex salinus colony, in central Washington state. In addition, large, jagged pebbles were either exposed by the erosion, or deposited around the nest entrance by the flowing water. In this series of images, dozens of workers can be seen attempting to remove the relatively huge rocks, by grasping them with their mandibles and dragging them away. Some of the objects appeared to be too large and heavy to be moved by a single ant, so in some instances, two or more workers would cooperatively carry them. It was also clear that the ants were completely unable to move some of the largest pebbles. Having a jumble of 'boulders' at the entrance to their nest would generally be unacceptable to these ants. The many nooks and crannies would make entering and exiting the nest very difficult (especially while carrying foraged seeds, etc), and spiders and other predators would be provided with many hiding places from which to prey upon colony members. In a situation like this, Pogos may sometimes choose to construct another nest entrance in a more suitable location.
ADDITIONAL NOTES/REFERENCES:
Many Pogo nests sport a prominent gravel-covered mound, cone, or crater which contains a small network of galleries and tunnels. In some cases, this mound feature is not present, and the external nest structure consists simply of entrance holes in the ground, often surrounded by a gravel 'disc', and located within an area cleared of vegetation.
However, like the proverbial 'tip of the iceberg', the above-ground portion of a Pogo nest represents only a tiny fraction of the whole colony - in terms of ant population, and in the physical structure and extent of the nest itself.
The subterranean portions of Pogonomyrmex nests usually contain one or more large (approximately vertical) tunnels - and branching off from these, many 'side burrows' and chambers. These offshoots are more numerous (and larger) nearer the surface, and dwindle in frequency and size, as depth increases. These chambers function as granaries, nurseries, general quarters, and sometimes refuse dumps.
Pogonomyrmex nests can reach considerable depths. Nests of P. rugosus (the rough harvester) have been shown to extend 4 m / 13 ft into the ground, and those of P.occidentalis have been recorded to reach depths of 3 m / 10 ft.
Along with distinct variations among different Pogo species, there are many variables that affect the proportions of a particular colony's nest. It's likely that most nests are somewhat shallower than the figures given above.
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
·Taber, S.W. 1998. The World of the Harvester Ants. College Station, TX, Texas A&M University Press.
·Wheeler, W.M. 1910. Ants: Their Structure, Development and Behavior. New York, Columbia University Press](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-pHvw4X4/0/Ti/3569_10_7Df-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/16/10 9:00AM partly cloudy, air temp: 23°C / 73°F
[IMAGE 1 of 6] Winter rains had apparently washed away most of the external nest mound of this Pogonomyrmex salinus colony, in central Washington state. In addition, large, jagged pebbles were either exposed by the erosion, or deposited around the nest entrance by the flowing water. In this series of images, dozens of workers can be seen attempting to remove the relatively huge rocks, by grasping them with their mandibles and dragging them away. Some of the objects appeared to be too large and heavy to be moved by a single ant, so in some instances, two or more workers would cooperatively carry them. It was also clear that the ants were completely unable to move some of the largest pebbles. Having a jumble of 'boulders' at the entrance to their nest would generally be unacceptable to these ants. The many nooks and crannies would make entering and exiting the nest very difficult (especially while carrying foraged seeds, etc), and spiders and other predators would be provided with many hiding places from which to prey upon colony members. In a situation like this, Pogos may sometimes choose to construct another nest entrance in a more suitable location.
ADDITIONAL NOTES/REFERENCES:
Many Pogo nests sport a prominent gravel-covered mound, cone, or crater which contains a small network of galleries and tunnels. In some cases, this mound feature is not present, and the external nest structure consists simply of entrance holes in the ground, often surrounded by a gravel 'disc', and located within an area cleared of vegetation.
However, like the proverbial 'tip of the iceberg', the above-ground portion of a Pogo nest represents only a tiny fraction of the whole colony - in terms of ant population, and in the physical structure and extent of the nest itself.
The subterranean portions of Pogonomyrmex nests usually contain one or more large (approximately vertical) tunnels - and branching off from these, many 'side burrows' and chambers. These offshoots are more numerous (and larger) nearer the surface, and dwindle in frequency and size, as depth increases. These chambers function as granaries, nurseries, general quarters, and sometimes refuse dumps.
Pogonomyrmex nests can reach considerable depths. Nests of P. rugosus (the rough harvester) have been shown to extend 4 m / 13 ft into the ground, and those of P.occidentalis have been recorded to reach depths of 3 m / 10 ft.
Along with distinct variations among different Pogo species, there are many variables that affect the proportions of a particular colony's nest. It's likely that most nests are somewhat shallower than the figures given above.
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
·Taber, S.W. 1998. The World of the Harvester Ants. College Station, TX, Texas A&M University Press.
·Wheeler, W.M. 1910. Ants: Their Structure, Development and Behavior. New York, Columbia University Press")
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/16/10 9:02AM partly cloudy, air temp: 23°C / 73°F
[IMAGE 2 of 6] Winter rains had apparently washed away most of the external nest mound of this Pogonomyrmex salinus colony, in central Washington state. In addition, large, jagged pebbles were either exposed by the erosion, or deposited around the nest entrance by the flowing water. In this series of images, dozens of workers can be seen attempting to remove the relatively huge rocks, by grasping them with their mandibles and dragging them away. Some of the objects appeared to be too large and heavy to be moved by a single ant, so in some instances, two or more workers would cooperatively carry them. It was also clear that the ants were completely unable to move some of the largest pebbles. Having a jumble of 'boulders' at the entrance to their nest would generally be unacceptable to these ants. The many nooks and crannies would make entering and exiting the nest very difficult (especially while carrying foraged seeds, etc), and spiders and other predators would be provided with many hiding places from which to prey upon colony members. In a situation like this, Pogos may sometimes choose to construct another nest entrance in a more suitable location.
ADDITIONAL NOTES/REFERENCES:
Many Pogo nests sport a prominent gravel-covered mound, cone, or crater which contains a small network of galleries and tunnels. In some cases, this mound feature is not present, and the external nest structure consists simply of entrance holes in the ground, often surrounded by a gravel 'disc', and located within an area cleared of vegetation.
However, like the proverbial 'tip of the iceberg', the above-ground portion of a Pogo nest represents only a tiny fraction of the whole colony - in terms of ant population, and in the physical structure and extent of the nest itself.
The subterranean portions of Pogonomyrmex nests usually contain one or more large (approximately vertical) tunnels - and branching off from these, many 'side burrows' and chambers. These offshoots are more numerous (and larger) nearer the surface, and dwindle in frequency and size, as depth increases. These chambers function as granaries, nurseries, general quarters, and sometimes refuse dumps.
Pogonomyrmex nests can reach considerable depths. Nests of P. rugosus (the rough harvester) have been shown to extend 4 m / 13 ft into the ground, and those of P.occidentalis have been recorded to reach depths of 3 m / 10 ft.
Along with distinct variations among different Pogo species, there are many variables that affect the proportions of a particular colony's nest. It's likely that most nests are somewhat shallower than the figures given above.
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
·Taber, S.W. 1998. The World of the Harvester Ants. College Station, TX, Texas A&M University Press.
·Wheeler, W.M. 1910. Ants: Their Structure, Development and Behavior. New York, Columbia University Press](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-DHpTZgr/0/Ti/3573_10_7Dc-Ti.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 5/16/10 9:02AM partly cloudy, air temp: 23°C / 73°F
[IMAGE 2 of 6] Winter rains had apparently washed away most of the external nest mound of this Pogonomyrmex salinus colony, in central Washington state. In addition, large, jagged pebbles were either exposed by the erosion, or deposited around the nest entrance by the flowing water. In this series of images, dozens of workers can be seen attempting to remove the relatively huge rocks, by grasping them with their mandibles and dragging them away. Some of the objects appeared to be too large and heavy to be moved by a single ant, so in some instances, two or more workers would cooperatively carry them. It was also clear that the ants were completely unable to move some of the largest pebbles. Having a jumble of 'boulders' at the entrance to their nest would generally be unacceptable to these ants. The many nooks and crannies would make entering and exiting the nest very difficult (especially while carrying foraged seeds, etc), and spiders and other predators would be provided with many hiding places from which to prey upon colony members. In a situation like this, Pogos may sometimes choose to construct another nest entrance in a more suitable location.
ADDITIONAL NOTES/REFERENCES:
Many Pogo nests sport a prominent gravel-covered mound, cone, or crater which contains a small network of galleries and tunnels. In some cases, this mound feature is not present, and the external nest structure consists simply of entrance holes in the ground, often surrounded by a gravel 'disc', and located within an area cleared of vegetation.
However, like the proverbial 'tip of the iceberg', the above-ground portion of a Pogo nest represents only a tiny fraction of the whole colony - in terms of ant population, and in the physical structure and extent of the nest itself.
The subterranean portions of Pogonomyrmex nests usually contain one or more large (approximately vertical) tunnels - and branching off from these, many 'side burrows' and chambers. These offshoots are more numerous (and larger) nearer the surface, and dwindle in frequency and size, as depth increases. These chambers function as granaries, nurseries, general quarters, and sometimes refuse dumps.
Pogonomyrmex nests can reach considerable depths. Nests of P. rugosus (the rough harvester) have been shown to extend 4 m / 13 ft into the ground, and those of P.occidentalis have been recorded to reach depths of 3 m / 10 ft.
Along with distinct variations among different Pogo species, there are many variables that affect the proportions of a particular colony's nest. It's likely that most nests are somewhat shallower than the figures given above.
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
·Taber, S.W. 1998. The World of the Harvester Ants. College Station, TX, Texas A&M University Press.
·Wheeler, W.M. 1910. Ants: Their Structure, Development and Behavior. New York, Columbia University Press")
● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3
![pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-salinus/i-rVKMsGp/0/M/3005_10_7Dc-M.jpg "pogolumina > ● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities \"...primarily due to the predominance of Bromus tectorum in the semi-desert areas.\" He also notes that \"the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively.\"
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that \"Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas.\"
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3")
● Wanapum Rec. Area [Kittitas Co], WA USA [el. 190 m / 623 ft] view location in Google Maps »
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
● 4/19/10 1:14PM sun, haze, air temp: 26°C / 79°F
[IMAGE 4 of 4] Spring is a busy time for Pogonomyrmex salinus workers. While some colony members forage, or conduct maintenance on the nest below, others engage in the removal of plants that have sprung up on, or too close to the nest mound. Even with their powerful mandibles, these ants struggle to cut through tough plant stems, and leaves. This series of images was captured on our first outing of 2010, in Washington state. A dozen or so workers from a small nest were busy cutting down cheatgrass (Bromus tectorum) growing on, and around the edges of the nest mound [see additional images » ]. One worker was seen attempting to drag a bunch of fallen spikelets, possibly back to the nest - though it was unclear, as she was making no progress, and soon abandoned the effort. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3
The introduced (and invasive) grass Bromus tectorum (cheatgrass), is common in many of the areas inhabited by Pogonomyrmex ants, and is often a target of their foraging activities.
One study in central Oregon found cheat grass (Bromus tectorum), to be one of the 5 most frequently collected seeds by P. salinus. The others were: Phacelia linearis, Hordeum jubatum, Descurainia pinnata, and Sisymbrium altissimum.
Pogonomyrmex occidentalis (a member of the same complex as P. salinus) has long been known to have an association with Bromus tectorum, though there are indications that this ant prefers other species when they are available. In the Twin Falls, Idaho area, Cole found the seeds of B. tectorum to be harvested in great quantities "...primarily due to the predominance of Bromus tectorum in the semi-desert areas." He also notes that "the seed chambers of mounds in dense bromegrass areas often contain a greater quantity of other seeds and only a few colonies were located which seemed to harvest bromegrass seeds exclusively."
This seems to be in keeping with the preliminary findings of a study of P. occidentalis in Colorado, by D. Wiernasz, where it was found that "Bromus tectorum was strongly avoided, and never exceeded 3% of seeds collected by foragers, even in high density areas."
·Cole, A.C. 1932a. The Relation of the Ant, Pogonomyrmex occidentalis CR., to its Habitat. Ohio Journal of Science, 32:133-46, Ohio State University
·Wiernasz, D. 2005. Granivore Activity on the Invasive Grass Bromus tectorum: a Factor in Establishment or Exclusion? University of Huston
·Willard, J.R. & H.H. Crowell. 1965. Biological Activities of the Harvester Ant, Pogonomyrmex owyheei, in Central Oregon. Journal of Economic Entomology Vol.58, No.3