Images of Pogonomyrmex californicus
- the California harvester at various locations in Nevada, and California, USA.
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!***
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 > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-RbGSqNS/1/Ti/4406_10_7Df-Ti.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.")
![pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 2 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest (cropped view).](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-PxQvJcZ/1/Ti/4406_10_7Dc-Ti.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 2 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest (cropped view).")
![pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:19AM partly cloudy, air temp: 17°C / 62°F
Finding a piece of plant matter, and picking it up with her mandibles - this Pogonomyrmex californicus worker heads back to the nest.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-s5Wqpf2/1/Ti/4398_10_7Dc-Ti.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:19AM partly cloudy, air temp: 17°C / 62°F
Finding a piece of plant matter, and picking it up with her mandibles - this Pogonomyrmex californicus worker heads back to the nest.")
![pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:36AM partly cloudy, air temp: 18°C / 64°F
A small Dorymyrmex sp. nest was located approximately 23 cm / 9 inches from the the nest of the Pogonomyrmex californicus worker seen here. Whenever a Pogo worker wandered near the smaller ants' nest, she would be harassed, and chased away. The Pogos were not observed to fight back - they simply ran a few inches away, and continued foraging. The Dorymyrmex workers were mostly performing maintenance on their nest, at the time these images were captured.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-dCxtMXN/0/Ti/4429_10_7Dc-Ti.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:36AM partly cloudy, air temp: 18°C / 64°F
A small Dorymyrmex sp. nest was located approximately 23 cm / 9 inches from the the nest of the Pogonomyrmex californicus worker seen here. Whenever a Pogo worker wandered near the smaller ants' nest, she would be harassed, and chased away. The Pogos were not observed to fight back - they simply ran a few inches away, and continued foraging. The Dorymyrmex workers were mostly performing maintenance on their nest, at the time these images were captured.")
![pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:36AM partly cloudy, air temp: 17°C / 62°F
While this looks like a fearsome defensive display, it is not. This Pogonomyrmex californicus worker has just dropped a load of coarse sand she had carried up from the subterranean depths of the nest. This kind of activity is ongoing, as the ants excavate new tunnels and galleries, and repair cave-ins. [scroll down for additional notes/references]
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-californicus/i-sZ4dqN5/0/Ti/4426_10_7Dc-Ti.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:36AM partly cloudy, air temp: 17°C / 62°F
While this looks like a fearsome defensive display, it is not. This Pogonomyrmex californicus worker has just dropped a load of coarse sand she had carried up from the subterranean depths of the nest. This kind of activity is ongoing, as the ants excavate new tunnels and galleries, and repair cave-ins. [scroll down for additional notes/references]
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 > ● Fernely [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:17AM partly cloudy, air temp: 17°C / 62°F
Another P.californicus worker foragingnear her nest, in northern Nevada, USA. If you click on this image to make it larger, the psammophore is clearly visible.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-FLCVqKk/0/Ti/4393_10_7Dc-Ti.jpg "pogolumina > ● Fernely [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:17AM partly cloudy, air temp: 17°C / 62°F
Another P.californicus worker foragingnear her nest, in northern Nevada, USA. If you click on this image to make it larger, the psammophore is clearly visible.")
![pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:38AM sunny, air temp: 22°C / 72°F
[IMAGE 1 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states "The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs."
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, "Apparently, this behavior does not occur or it is very uncommon."
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-mMDSJFc/0/Ti/4347_10_7Dc-Ti.jpg "pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:38AM sunny, air temp: 22°C / 72°F
[IMAGE 1 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states \"The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs.\"
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, \"Apparently, this behavior does not occur or it is very uncommon.\"
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149")
![pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:45AM sunny, air temp: 22°C / 72°F
[IMAGE 2 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states "The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs."
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, "Apparently, this behavior does not occur or it is very uncommon."
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-KPsVSR5/1/Ti/4365_10_7Dc-Ti.jpg "pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:45AM sunny, air temp: 22°C / 72°F
[IMAGE 2 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states \"The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs.\"
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, \"Apparently, this behavior does not occur or it is very uncommon.\"
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149")
![pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:46AM sunny, air temp: 22°C / 72°F
[IMAGE 3 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states "The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs."
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, "Apparently, this behavior does not occur or it is very uncommon."
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-hg9ZwJn/1/Ti/4367_10_7Dc-Ti.jpg "pogolumina > ● Pyramid Lake Indian Res. (Paiute), NV USA [el. 1202 m / 3945 ft] view location in Google Maps »
● 6/22/10 9:46AM sunny, air temp: 22°C / 72°F
[IMAGE 3 of 3] The ability of Pogonomymrex ants to carry excavated sand in their psammophores is well known and documented. But, despite a few vague references on the Web [1], we have not yet found any descriptions of these ants using this structure to gather and/or transport seeds in the wild, under natural conditions [2] (nor have we observed this behavior ourselves, prior to 6/22/10).
These Pogonomyrmex californicus workers were picking up (and transporting) multiple seeds of Descurainia sophia (a.k.a. flixweed). The nest of these ants was located in a sandy area, under a living Salsola (tumbleweed) plant - surrounded by many other plants including (and most abundantly) Descurainia sophia.
The multiple-seed-gathering behavior was taking place approx. 60 cm / 2 feet away from the nest entrance - in an area strewn with the tiny orange D. sophia seeds. It was probably the high density of seeds (estimated to be 0.3 - 0.5 per cm²), along with their small size and proximity to the nest, that made this unusual type of foraging possible [2]. Workers returning from other areas, and from greater distances, carried only single items (as is usual for these ants). Individual workers were observed to successfully carry three of these seeds at a time, usually with one in the psammophore, and two 'stacked' in the mandibles (one worker was seen to have two seeds, side by side, in the psammophore). As can be seen in these images, the Pogos sometimes used the tips of their antennae to maneuver the seeds into position, before attempting to pick them up. Once fully loaded, they headed straight for the nest. There were many empty seedpods in the area where the seeds were being gathered, and it is possible that the ants had broken open the pods earlier and liberated the seeds - but it is just as likely that the seeds fell naturally. One worker was seen manipulating a seedpod, but it was already empty. [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1] Most notably, the Wikipedia article on Pogonomyrmex states \"The psammophore are (sic) used for gathering small seeds, helping to increase the efficiency of transportation of fine sand and pebbles during nest construction, or to carry eggs.\"
[2] Pogonomyrmex ants have been known to transport multiple food items (using the psammophore and mandibles) when presented with bait piles consisting of cracked wheat, during controlled experiments. These bait piles offered the ants very small particles, at higher densities than would be found under natural conditions. During these experiments, P.occidentalis workers did not start using their psammophores until seed densities exceeded 0.5 cm² As far as the use of psammophores by foragers under natural conditions, Porter & Jorgensen state, \"Apparently, this behavior does not occur or it is very uncommon.\"
·Porter, S.D., and C.D. Jorgensen. 1990. Psammophores: Do Harvester Ants (Hymenoptera: Formicidae) Use These Pouches to Transport Seeds? Journal of the Kansas Entomological Society. 63(1) 138 -149")
![pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:53AM sunny, air temp: 16°C / 60°F
[IMAGE 1 of 2] On the shores of the Salton Sea in southern California, a Pogonomyrmex californicus worker has been captured by a theridiid spider (spider ID coming soon). This took place about 60 cm / 2 ft from the P. californicus nest.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-3dw2pXp/1/Ti/7860_11_7D-Ti.jpg "pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:53AM sunny, air temp: 16°C / 60°F
[IMAGE 1 of 2] On the shores of the Salton Sea in southern California, a Pogonomyrmex californicus worker has been captured by a theridiid spider (spider ID coming soon). This took place about 60 cm / 2 ft from the P. californicus nest.")
![pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:53AM sunny, air temp: 16°C / 60°F
[IMAGE 2 of 2] On the shores of the Salton Sea in southern California, a Pogonomyrmex californicus worker has been captured by a theridiid spider (spider ID coming soon). This took place about 60 cm / 2 ft from the P. californicus nest.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-37964Fj/1/Ti/7863_11_7D-Ti.jpg "pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:53AM sunny, air temp: 16°C / 60°F
[IMAGE 2 of 2] On the shores of the Salton Sea in southern California, a Pogonomyrmex californicus worker has been captured by a theridiid spider (spider ID coming soon). This took place about 60 cm / 2 ft from the P. californicus nest.")
![pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:30AM sunny, air temp: 14°C / 58°F
[IMAGE 1 of 2] A native fire ant worker (Solenopsis xyloni) clings to the leg of a Pogonomyrmex californicus worker. While several such battles were taking place, a group of fire ants were hastily blocking the entrance to their nest, possibly in response to a raid by the larger Pogos. The S. xyloni and P. californicus nests were about 8 feet apart. Note that the fire ant (smaller ant in images) has been bitten in half, but still continues to struggle.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-xJ5hG5f/1/Ti/7826_11_7D-Ti.jpg "pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:30AM sunny, air temp: 14°C / 58°F
[IMAGE 1 of 2] A native fire ant worker (Solenopsis xyloni) clings to the leg of a Pogonomyrmex californicus worker. While several such battles were taking place, a group of fire ants were hastily blocking the entrance to their nest, possibly in response to a raid by the larger Pogos. The S. xyloni and P. californicus nests were about 8 feet apart. Note that the fire ant (smaller ant in images) has been bitten in half, but still continues to struggle.")
![pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:32AM sunny, air temp: 14°C / 58°F
[IMAGE 2 of 2] A native fire ant worker (Solenopsis xyloni) clings to the leg of a Pogonomyrmex californicus worker. While several such battles were taking place, a group of fire ants were hastily blocking the entrance to their nest, possibly in response to a raid by the larger Pogos. The S. xyloni and P. californicus nests were about 8 feet apart. Note that the fire ant (smaller ant in images) has been bitten in half, but still continues to struggle.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-4w3WcZW/2/Ti/7834_11_7D-Ti.jpg "pogolumina > ● Sea Port Ave, Salton City, CA USA [el. -60 m / -200 ft] view location in Google Maps »
● 4/09/10 9:32AM sunny, air temp: 14°C / 58°F
[IMAGE 2 of 2] A native fire ant worker (Solenopsis xyloni) clings to the leg of a Pogonomyrmex californicus worker. While several such battles were taking place, a group of fire ants were hastily blocking the entrance to their nest, possibly in response to a raid by the larger Pogos. The S. xyloni and P. californicus nests were about 8 feet apart. Note that the fire ant (smaller ant in images) has been bitten in half, but still continues to struggle.")
![pogolumina > ● Split Mountain area, Anza-Borrego Desert S.P., CA USA [el. 119 m / 390 ft] view location in Google Maps »
● 4/06/10 10:19AM sunny, air temp: 27°C / 81°F
[IMAGE 1 of 2] Pogonomyrmex californicus workers just outside the entrance to their nest in Anza-Borrego Desert State Park, CA USA.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-dMNpc4m/2/Ti/7509_11_7D-Ti.jpg "pogolumina > ● Split Mountain area, Anza-Borrego Desert S.P., CA USA [el. 119 m / 390 ft] view location in Google Maps »
● 4/06/10 10:19AM sunny, air temp: 27°C / 81°F
[IMAGE 1 of 2] Pogonomyrmex californicus workers just outside the entrance to their nest in Anza-Borrego Desert State Park, CA USA.")
![pogolumina > ● Split Mountain area, Anza-Borrego Desert S.P., CA USA [el. 119 m / 390 ft] view location in Google Maps »
● 4/06/10 10:20AM sunny, air temp: 27°C / 81°F
[IMAGE 2 of 2] Pogonomyrmex californicus workers just outside the entrance to their nest in Anza-Borrego Desert State Park, CA USA.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-QHc73CK/2/Ti/7510_11_7D-Ti.jpg "pogolumina > ● Split Mountain area, Anza-Borrego Desert S.P., CA USA [el. 119 m / 390 ft] view location in Google Maps »
● 4/06/10 10:20AM sunny, air temp: 27°C / 81°F
[IMAGE 2 of 2] Pogonomyrmex californicus workers just outside the entrance to their nest in Anza-Borrego Desert State Park, CA USA.")
● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.
![pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.](http://www.pogolumina.net/NorthAmericanPogosbySpecies/Pogonomyrmex-californicus/i-RbGSqNS/1/M/4406_10_7Df-M.jpg "pogolumina > ● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.")
● Fernley [Lyon Co], NV USA [el. 1271 m / 4171 ft] view location in Google Maps »
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
● 6/23/10 6:27AM partly cloudy, air temp: 17°C / 62°F
[IMAGE 1 of 2] A beautiful Pogonomyrmex californicus worker pauses briefly after emerging from her nest.