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The Main Ant Pages On Wayne's Word: Images Taken With Nikon & Sony Cameras
  Ant Genera Index        Introduction        Ant Page 1        Ant Page 2        Ant Page 3        Nikon        Sony  
Ant Page #2: Subfamilies In The S.W. US,
Hawaiian Islands & Other Tropical Regions
   © W.P. Armstrong 12 May 2013     More On Imported Fire Ants   
Images Of Ant Subfamilies In Bug Guide
Ant Genera Photographed By Alex Wild
Ant Images From Arizona October 2012
Ant Images From Arizona Feb 2013 (#1)
Ant Images From Arizona Feb 2013 (#2)
Images From Salton Sea April 2013 (#1)
Images From Salton Sea April 2013 (#2)
Ant Images On Hawaiian Island Of Maui
  Disclaimer: I am reasonably certain about most of the identifications, especially those verified by James Trager & Alex Wild. For some of the names I used cf. (compare with) because of the difficulty in separating very similar species. On others I simply placed the ants in their respective subgroups of closely-related species. Large, difficult genera often require a specialist for precise species verification. Although identifications from my photo images may be impossible without voucher specimens to examine, comments and/or suggestions about my identifications are welcome.
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Carpenter Ant (Family Formicidae: Subfamily Formicinae )

Hawaiian carpenter ant (Camponotus variegatus), the largest ant species in the Hawaiian Islands. This specimen appears to be a queen who has shed her wings.

Carpenter Ant At Chesapeake Bay (Camponotus pennsylvanicus)

Eastern black carpenter ant (Camponotus pennsylvanicus) at Chesapeake Bay, Maryland.


Carpenter Ant On Owens Peak (Camponotus dumetorum)

  Go Back To Table Of Ant Images From Owens Peak     Click Here  

Western carpenter ant (Camponotus dumetorum), a large carpenter ant native to the western United States. Major workers can be up to 10 mm or more in length, larger than most harvester ants in this region. Identified by James Trager: It has a carinate clypeus and a lobe at base of scape.

A carpenter ant worker (Camponotus sp.) on north side of Owens Peak.


More Dark Carpenter Ants On Owens Peak (Camponotus dumetorum)

  Go Back To Table Of Ant Images From Owens Peak     Click Here  


A carpenter ant major worker (probably Camponotus dumetorum) along a dirt road through chaparral in the Merriam Mtns of San Diego County. This is a large California ant up to 10 mm in length. In southern California it commonly builds nests in the ground. Another shiny black species (C. laevigatus) is found in coniferous logs at higher elevations in the mountains. Camponotus gigas of Southeast Asia has one of the largest workers, each measuring about 30-40 mm in length (see next image).

Some species of carpenter ants can chew through wood causing structural damage; however, they do not digest wood cellulose like termites. Termite guts contain flagellated protists that contain wood-digesting bacteria, which in turn contain cellulose-digesting enzymes.

  San Marcos & Merriam Mountains  
See Wayne's Word Termite Page


Large Carpenter Ant On Palomar Mountain
I originally thought the following images were Camponotus vicinus; however, they greatly resemble C. semitestaceus at Daley Ranch. My photos of the Daley Ranch species were identified by entomologist Dr. James Trager (personal communication, 27 August 2015). Although C. semitestaceus is quite variable in color, it is the most common member of the vicinus-complex in San Diego County.

This is not a wasp! It is a large queen carpenter ant (probably Camponotus vicinus) almost 20 mm in length. It was discovered under a pillow in a friend's bed who lives on Palomar Mountain.


Major & Minor Workers Of Camponotus fragilis On Owens Peak

  Go Back To Table Of Ant Images From Owens Peak     Click Here  

Carpenter ants (Camponotus fragilis). These large, orange-yellow ants came out of a crack in the metavolcanic rock outcrop at the summit of Owens Peak. They are described as being nocturnal. Although not visible in the above images, erect setae are present along the head margin of major worker. Although carpenter ants of the genus Camponotus typically nest in wood, this is a ground-dwelling species with its nest under a large boulder. The body of the larger (major) worker was 7-8 mm long. Both ants appeared near the entrance to a nest of southern fire ants (Solenopsis xyloni). This area was also the scene of a major encounter between native fire ants and foraging Forelius pruinosus (or F. mccooki). Thanks to Alex Wild for the identification (www.alexanderwild.com).

Carpenter ants (Camponotus fragilis): The smaller, minor worker placed its mandibles in the open jaws of the larger major worker, presumably sharing food (trophallaxis). In my container they repeatedly assumed this position. Wikipedia shows another species of Camponotus exhibiting this behavior.

The following abstract is from PubMed (The National Center for Biotechnology Information): "Trophallaxis and Prophylaxis: Social Immunity in the Carpenter Ant Camponotus pennsylvanicus" by C. Hamilton, B.T Lejeune, and R.B. Rosengaus (23 February, 2011).

In social insects, group behaviour can increase disease resistance among nest-mates and generate social prophylaxis. Stomodeal trophallaxis, or mutual feeding through regurgitation, may boost colony-level immunocompetence. We provide evidence for increased trophallactic behaviour among immunized workers of the carpenter ant Camponotus pennsylvanicus, which, together with increased antimicrobial activity of the regurgitate droplet, help explain the improved survival of droplet recipient ants relative to controls following an immune challenge. We have identified a protein related to cathepsin D, a lysosomal protease, as a potential contributor to the antimicrobial activity. The combined behavioural and immunological responses to infection in these ants probably represent an effective mechanism underlying the social facilitation of disease resistance, which could potentially produce socially mediated colony-wide prophylaxis. The externalization and sharing of an individual's immune responses via trophallaxis could be an important component of social immunity, allowing insect colonies to thrive under high pathogenic pressures.

The Camponotus fragilis major worker is similar to C. absquatulator in color and stature, except it has erect setae along entire head margin. It differs from C. festinatus by its smaller size and by the lack of standing setae on the side of the pronotum.

The following distribution for Camponotus fragilis comes from www.antwiki.org:

United States, Mexico. Camponotus fragilis occurs over most of the Lower California peninsula as far north on the Gulf of California coast at least to Bahía de los Angeles and northwest into southern California via San Diego County. It is also present on most, if not all, the islands of the Gulf of California and in the State of Sonora and north into Arizona (Tempe, Maricopa Co., the easternmost record) in the United States; from Sonora it ranges south along the coast to Nayarit: specimens that I collected on the Tres Marías Islands apparently are referable to C. fragilis. In California C. fragilis appears to be uncommon and is replaced in the lower desert of Imperial and Riverside Counties by Camponotus absquatulator. It is present in chaparral habitat in San Diego County, north to Riverside County and is found at mid-elevation sites along the margins of the lower desert, extending north into the Mojave Desert at least as far as the Old Woman Mountains (1.2 km S Sunflower Springs, 945 m), San Bernardino County. (Snelling 2006).


The remarkable Malaysian giant ant (Camponotus gigas), one of the world's largest ants native to rain forests of Southeast Asia. In case you are unfamiliar with the size of a U.S. Penny, see the following image.


The Infamous Bullet Ant (Subfamily Paraponerinae): Paraponera clavata

Bullet ant (Paraponera clavata), another large tropical ant. This species is native to Central and South America. It is a little smaller than the Malaysian giant ant, but makes up for its size difference with the most painful sting of all insects. It is rated 4.0+ on the Schmidt Sting Pain Index (see following table). It is called "bullet ant" because sting is compared with the pain of a bullet.

According to Schmidt (1986), the venom of Paraponera is a small neuropeptide called poneratoxin. It blocks the central nervous system of insects and is agonistic to mammalian smooth muscle (agonistic toxins mimic the effects of neurotransmitters while antagonistic toxins blocks neurotransmitters). In humans, intense pain may last for 5 hours, then lessen over the next 24 hours. Severe pain may be accompanied by trembling, perspiration, nausea, and inability to use an injured arm or leg. Some South American Indians intentionally apply stings during tribal manhood rituals and medicinally as a counter-irritant to relieve rheumatism and similar ailments. These remarkable ants have reportedly been used for sutures to close open wounds. After locked jaws hold the skin together the heads are twisted off. The unfortunate ants are probably not too happy with this primitive method of suturing. East African indigenous people use siafu or driver ants (Dorylus) in a similar way. They use large-headed soldiers to stich the wound by getting the ants to bite on both sides of the gash, then breaking off the body.

Bullet ants can incapacitate larger animals, including humans. Keepers of these ants in zoos are required to follow strict safety guidelines for dangerous venomous animals. This includes treatment protocols with Benadryl, Prednisone, and self-injectable epinephrine.

Schmidt Sting Pain Index

Sting Rating
Hymenopteran
Comparison Analogy
1.0
Sweat Bee
Like a tiny spark has has singed a hair on your arm.
1.2
Fire Ant
Like walking on a carpet & getting a static electricity shock.
1.8
Bullhorn Acacia Ant
Like someone fired a staple into your cheek or hand.
2.0
Bald-Faced Hornet
Like getting your hand mashed in a revolving door.
2.0
Yellowjacket
Like extinguishing a cigar on your tongue.
2.0+
Honey Bee
Like a burning matchhead that lands on your skin.
3.0
Red Harvester Ant
Like using a drill to excavate your ingrown toenail.
3.0
Paper Wasp
Like spilling a beaker of hydrochloric acid on a paper cut.
4.0
Pepsis Wasp
Like dropping a running hair drier into your bubble bath.
4.0+
Bullet Ant
Walking on hot charcoals with 3 inch rusty nail in your heel.

Man Testing Sateré-Mawé Tribal Initiation With Bullet Ants In Amazon
  The Sateré-Mawé Tribal Initiation Using Bullet Ants In Brazilian Amazon  


Other Potentially Dangerous Ants In Africa & Australia

Siafu (Dorylus gribodoi) Courtesy of April Nobile/ © Ant Web.org
African "army ants" of the genus Dorylus (subfamily Ecitoninae) are often called driver ants or siafu. The live in enormous colonies containing over 20 million individuals. They go on seasonal marching columns of 50,000,000 ants in search of food. Columns are arranged with smaller worker ants being flanked by larger soldier ants. They can potentially devour any animal that remains in their path. Since they consume crop pests, from insects to rats, they are actually quite beneficial to indigenous people. They pose a serious threat to any animals unable to move or when the columns pass through homes. Soldiers have very large and powerful mandibles, and their bite is painful.

Jack Jumper (Myrmecia pilosula) Courtesy of Shannon Hartman / © Ant Web.org
Large, aggressive Australian ants of the genus Myrmecia (subfamily Myrmeciinae) can reach 40 mm in length. They are called bulldog ants or "jack jumpers." Their painful stings are dangerous because they may induce anaphylactic shock in allergic victims. Like honey bees and other hymenopterans, female ants are typically diploid with 2 sets of chromosomes. Males are haploid and develop from unfertilized eggs. The Australian jack jumper worker ant (Myrmecia pilosula) has only a single pair of chromosomes. Male jack jumpers have only one chromosome, the lowest number known for any animal!

Left: Jack jumper worker (Myrmecia pilosula) from southern Australia. Courtesy of Shannon Hartman 2011 www.antweb.org. Retrieved 24 May 2013.


Trap-jaw Ant (Ponerinae): Odontomachus coquereli

Odontomachus coquereli: Trap-jaw ant native to Madagascar. April Nobile © antweb.org


Trap-Jaw Ant (Odontomachus bauri) From Costa Rica

Trap-jaw ants of the genus Odontomachus have a pair of large, straight mandibles capable of opening 180 degrees. The jaws are locked in place by a pair of large contracting muscles in the head, and can snap shut on prey or objects when their corresponding latches on the clypeus are triggered. The great instantaneous speed of the muscles is due to elastic energy, like the elastic energy of a crossbow. According to Wikimedia (2013), the jaws of Odontomachus are the fastest moving predatory appendages in the animal kingdom. One study of O. bauri (see next image) at UC Berkeley's Department of Integrative Biology (2006) recorded peak speeds of between 35-64 meters per second (78-145 mph), with the jaws closing within just 0.13 milliseconds (130 microseconds) on average. This is 2,300 times faster than the blink of an eye! The peak force exerted was 100,000 times the force of gravity or 300 times the ant's body weight. The mandibles either kill or maim prey, allowing the ant to bring it back to the nest. Odontomachus can simply open and relock its jaws if one bite is not enough. It can use its jaws to bite off larger chunks of food. The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backwards to escape a threat.

The Costa Rican trap-jaw ant (Odontomachous bauri).

According to Sheila Patek of the integrative biology research team at UC Berkeley (2006), falcons can dive at speeds up to 300 miles per hour, but they must start from very high altitudes and get a boost from the force of gravity to reach these high speeds (32 feet per second squared). In comparison, animals such as trap-jaw ants and mantis shrimp (which formerly held the record for swiftest strike in the animal world) utilize energy stored within their own bodies. In the plant kingdom, one of the fastest moving structures is the trapdoor of an aquatic bladderwort (Utricularia) that snaps shut in 15 to 20 milliseconds (about 1/60 of a second), roughly the speed of a daylight film camera shutter setting. Compare this rate with 0.13 milliseconds for jaws of Odontomachus bauri! Using the formula Force = Mass X Acceleration, it is easy to see how these small ants can stun or kill small prey with their powerful, fast-moving jaws.

.
Patek, S.M., Baio, J.E., Fisher, B.L., and A.V. Suarez. 2006. "Multifunctionality and Mechanical Origins: Ballistic Jaw Propulsion in Trap-Jaw Ants." Proceedings of the National Academy of Sciences 103 (34): 12787-12792. Full Article

Remarkable Trapdoor Of A Bladderwort (Utricularia)
 See Wayne's Facebook Trivia Note About Trap-jaw Ant
 

More Images Of Odontomachus bauri From Costa Rica


Arizona's Trap-jaw Ant (Ponerinae): Odontomachus clarus


Mandibles Locked In Opened Position
Photo by Zach Lieberman. From www.Antweb.org

Mandibles Released In Closed Position
Photo by April Nobile. From www.Antweb.org
I have yet to encounter this species on my Arizona photographic road trips. Stay tuned.


Gray Field Ant (Subfamily Formicinae): Formica moki

  Go Back To Table Of Ant Images From Owens Peak     Click Here  

This ant identified by James Trager as Formica moki. It was found along a dirt road through the coastal sage scrub north of Owens Peak. This is a common ant in southern California, one of the ant species I played with as a child. The body length (excluding long legs) is about 5-6 mm long. This species moves in a jerky motion and does not trail.

The gray field ant nests in coastal hills of southern California, including Owens Peak and Daley Ranch. Its range extends south to Mexico and north to the northwestern corner of Arizona, southern Nevada, northern California and Oregon. Although it is a medium-sized, aggressive ant, its nest is sometimes invaded by slave-making ants (Polyergus vinosus). The slave-maker ants have sickle-shaped jaws for killing and carrying prey, but useless for tasks that worker slave ants must perform. I have yet to encounter raiding parties of Polyergus in southern California.

A. Tapinoma sessile foraging on achenes in the inflorescence of California sagebrush (Artemisia californica) on Owens Peak. B. Formica moki foraging on achenes in the pistillate flower head of a female coyote bush (Baccharis pilularis ssp. consanguinea) on Owens Peak.


Northern Field Ant (Subfamily Formicinae): Formica subsericea

I am reasonably certain this is Formica subsericea. It was sent to me from Orleans, Canada, a suburb of Ottawa, Ontario. This is definitely a species that can survive very cold winters with permafrost. It is common across the northern Unted States and Canada.


Black Garden Ant (Subfamily Formicinae): Lasius niger & L. alienus
Another Common Ant Of The Northern United States & Eastern Canada

This Eurasian ant is also common across the northern United States and eastern Canada. The genus Lasius is similar to Formica but has a markedly different-shaped propodeum when observed in profile view.

Lasius alienus (cornfield ant) from Ontario, Canada: This species has a widespread distribution across North America and Europe. It is very similar to L. niger. The genus Lasius is similar to Formica but has a markedly different-shaped propodeum when observed in profile view.


Wood Ant or Thatching Ant (Subfamily Formicinae): Formica integroides

Thatching Ants On Alligator Juniper In Prescott, Arizona

Nest of alligator juniper branchlets (Juniperus deppeana) teaming with thatching ant workers.

Juniper branchlets teaming with aggressive thatching ant workers (Formica integroides).

This high Sierra Nevada species of Formica (cf. Formica oreas) was photographed near Sage Hen Creek. The head and thorax are brighter red than some of the southern California species.


Honeypot Ant (Subgenus Eremnocystus): Myrmecocystus in Cucamonga, CA

According to James Trager (BugGuide.net) this species belongs to the genus Myrmecocystus. The long maxillary palps are characteristic of that genus. It was found in a gravelly field in Cucamonga, California not far from the nest of a California harvester ant (Pogonomyrmex californicus). It has an acidopore and the body length (excluding antennae) is about 5 mm long. Using the Antwiki Key To Myrmecocystus Species, it appears to match the southern California species M. creightoni; however, I am not 100% certain. The closely related M. lugubris has more erect hairs on thorax, but is otherwise very similar.

Key To Species Of Myrmecocystus
Myrmecocystus Near The Salton Sea
  Myrmecocystus Near Holbrook, Arizona  

I originally (incorrectly) thought the previous ant was in the Formica Subsericea Complex

The "Formica Subsericea Complex" includes F. subsericea, F. argentea and F. podzolica. Ants of the "Subsericea Complex" occur in the cold northern latitudes. For example F. podzolica occurs in podzolic soils of the Boreal Forest Biome of the northern U.S. and Canada. These are gray-brown soils found primarily on sandy parent materials underlain by igneous rocks of the Canadian Shield.

Close-up view of mandibles of Myrmecocystus ant from Cucamonga. The mandibles have 6 teeth. Ants in the genus Formica have mandibles with 7 or more teeth.


Harvester Ant (Formicidae: Subfamily Myrmicinae)

Desert harvester ant (Messor pergandei).

Harvester ants carrying the plumose achenes of smooth cat's ear (Hypochaeris glabra). This is presumably the widespread Messor pergandei. Nests of the red California harvester ant (Pogonomyrmex californicus) are nearby and the two species appear to tolerate each other. These ants provide the vital diet for the coast horned lizard (Phrynosoma coronatum). Unfortunately, our native ants have been eliminated throughout coastal San Diego County by the aggressive Argentine ant (Iridomyrmex humilis).

  Desert Harvester Ants & Dyeweed  

A seemingly endless supply of Hypochaeris achenes, each with a plumose pappus resembling a miniature parachute. Like the dandelion, this naturalized plant is well-adapted for wind dispersal.

Harvester Ants (Messor) & Filaree (Erodium cicutarium)

Harvester ants of the genus Messor and husks of Erodium cicutarium (blue arrow).

Black Harvester Ants (Messor andrei) on Owens Peak in San Marcos, CA

  Go Back To Table Of Ant Images From Owens Peak     Click Here  

Until recently I thought this species of Messor on Owens Peak was M. pergandei; however, close examination of the head revealed that it was a different species (M. andrei). It is much hairier than M. pergandei and the head has conspicuous parallel lines (grooves). In addition it is monomorphic while M. pergandei colonies in San Diego County are polymorphic. Because of its hairiness M. andrei doesn't appear as shiny black as M. pergandei.

Harvester ant (Messor andrei) on Owens Peak: After giving the colony a water-saturated cotton ball and Nature Valley Granola (which they seemed to enjoy), they still went ahead and bit the hand that fed them. At least they can't sting!


California Harvester Ant (Subfamily Myrmicinae cf. Pogonomyrmex subnitidus)

Harvester ant (Pogonomyrmex subnitidus). This species is very similar to Pogonomyrmex californicus and is listed as a subspecies of the latter species in some references. Along with Messor species it is the main diet of the coast horned lizard.

  Go Back To Table Of Ant Images From Owens Peak     Click Here  

Left: Magnified view of the head of a desert harvester ant (Messor pergandei). Messor species are also called "smooth" harvester ants. Right: California harvester ant (Pogonomyrmex californicus). Note hairs and parallel vertical lines (grooves) on red harvester ant. Pogonomyrmex species are also called "rough" harvester ants. [B & L dissecting microscope with Sony V-3.]

The hairs and parallel vertical lines (grooves) on the head of Messor andrei quite different from the smooth, glossy head of M. pergandei.

  See Harvester Ants In Anza-Borrego Desert  
See Harvester Ants In Anza-Borrego Desert


Arizona Harvester Ant (Formicidae: Pogonomyrmex barbatus)

Clearing 10 feet (3 m) across made by colony of harvester ants (Pogonomyrmex barbatus). The ants carefully remove all plants and competing root systems from their subterranean nest.

Colony of harvester ants (Pogonomyrmex barbatus) near Cottonwood, Arizona.

Colony of harvester ants (Pogonomyrmex rugosus) along road from Banning To Idyllwild.

Harvester Ant Workers In Arizona: Hybrids Between Pogonomyrmex rugosus & P. barbatus

Sex determination in the more than 12,000 species of ants is typical of the enormous insect order Hymenoptera, including bees and wasps. The method is called "haplodiploidy." Males develop from unfertilized eggs and are haploid with one set of maternal chromosomes. They are not identical clones of their queen mother because of crossing over and random assortment of chromosomes during meiosis (oogenesis). Deleterious (unfavorable) recessive genes are quickly weeded out in haploid males because they are expressed and cannot be masked by dominant genes. Females develop from fertilized eggs and are diploid with two sets of chromosomes. Some references say that larvae destined to become sexually mature queens are "well-nurtured," presumably similar to royal jelly in honey bees; however, other reputable authorities state that selection of a queen in some ant species is a lot more complicated and may involve special eggs destined to become queens (see next paragraph). Queen ants have one of the longest life-spans of any known insects--up to 28 years in captivity!

In zones of hybridization, Pogonomyrmex harvester ant workers of the southwestern U.S. are hybrids between P. rugosus and P. barbatus. They possess the best genetic traits of two species. The queen of each species mates with the males of opposite species. Sexually mature ants (queens and winged males) are purebreds: They are offspring of queen and males of the same species. Young queens need to mate with their own species to produce more purebred queens. They need to mate with the other species to produce "superorganism" workers. This strategy appears to be evolutionarily advantageous to both species.

  1. Cahan, S.H., and L. Keller. 2003. "Complex Hybrid Origin of Genetic Caste Determination in Harvester  
      Ants." Nature 424 (6946): 306-309.

  2. Schwander, T., Cahan, S.H., and L. Keller. 2007. "Characterization and Distribution of Pogonomymex  
      Harvester Ant Lineages with Genetic Caste Determination." Molecular Ecology 16 (2): 367-387.

  3. Schwander, T., and L. Keller. 2007. "Genetic Compatibility Affects Queens and Worker Caste  
      Determination." Science 322 (5901): 552.

Comparison Of Pogonomyrmex Hybrid Workers With A Mule

If the workers of an ant nest can be thought of as the superorganism's body, and the sexuals (queens & males) can be thought of as the superorganism's genetic material, it is as though an animal with the body of a mule has the genetic make-up of a horse and donkey!

Although Pogonomyrmex hybrid workers form a colony and the mule is a single organism, they make an interesting comparison. They both involve a cross between two species that forms a stronger hybrid offspring with the best traits of its parents. The ant colony of hybrid workers functions as a unit that could be described as a "superorganism."

The female horse (mare) mates with a male horse (stallion) to produce more male and female horses. If she mates with a male donkey (jackass) she can produce a male or female mule. The mule is a sterile hybrid with the body size of a horse and the sure-footedness and endurance of a donkey. That is why the mule is essentially a "superorganism" used as a powerful pack animal. In the case of Pogonomyrmex, the hybrid "super-ants" are the workers!

An original 20 mule team wagon train used in 1885 to haul borax from Death Valley to Mojave, a distance of 165 miles. The borax weighed 24 tons and the entire wagon train weighed 36.5 tons (gross weight). The last wagon carried water for the mules during the hot, 10 day journey across the Mojave Desert. Today, a load of this size would be pulled by a 600 horse power Kenworth T-2000 tractor with an air conditioned cab!
  More Information About The Mule On Wayne's Word  


Argentine Ant (Formicidae: Subfamily Dolichoderinae) Linepithema humile

Argentine ants (Linepithema humile): A wingless queen and several workers. Although these ants are only 3 mm long, they are very aggressive and quickly annihilate other ant species, even larger ants with powerful jaws and stings. They overpower other species by their sheer numbers. Argentine ants in the U.S. are descendants of original colonizers that entered Louisiana in the late 1890's, as coffee ships from Brazil unloaded their cargo in New Orleans. U.S. populations are so closely related that different colonies with multiple queens can literally merge together into supercolonies. Image taken with Nikon D-90 and 60mm Micro Nikkor AF-S F/2.8G ED Macro Lens using a Phoenix Ring Flash; hand-held at 640 ISO, F-32, 1/125th sec.

  More Information About The Argentine Ant  


Velvety Tree Ant (Subfamily Dolichoderinae) Liometopum occidentale

These aggressive, biting ants give off a pungent odor if disturbed.


Pseudomyrmecinae: Pseudomyrmex apache On Owens Peak
This species is sometimes called the "amber twig ant" or "golden twig ant" because of its color and habit of nesting in hollow stems of shrubs and trees. The related acacia ant nests in the hollowed-out thorns (paired stipular spines) of swollen-thorn acacias in Central America. The latter ant species has evolved a remarkable symbiotic relationship with acacia trees (genus Acacia) that rivals the coevolution of the fig and fig wasp.

  See Techniques For Photographing Live Ants  

The above image shows a single amber twig ant collected 1 November 2013 on the stem of a flowering female shrub that keys out to chaparral broom B. sarothroides, although it is probably a fall-blooming B. pilularis. All of the nearby shrubs are coyote brush (Baccharris pilularis), and I have often seen scattered shrubs in B. pilularis populations that more closely resemble chaparral broom (B. sarothroides), particulary in the fall-blooming months. Other ants in the area (Tapinoma sessile and Formica aerata) appeared interested in the numerous flowering heads of seed-bearing achenes on female coyote brush.

  See Nearby Foraging Tapinoma sessile & Formica aerata)  

The above ant is Pseudomyrmex apache. Its range includes the southwestern United States and Mexico. It is also reported from nearby Laguna Beach. P. pallidus is very similar and is known from the southern U.S. and Mexico, south to Costa Rica. The identification of P. apache was confirmed by authorities Dr. Alex Wild, University of Illinois and Phil Ward, University of Calif, Davis (personal communication, 4 November 2013). This species belongs to the same genus as the acacia ant (P. ferruginea) of Costa Rica that lives symbiotically with swollen-thorn acacia trees.

An unusual discovery on Owens Peak: Pseudomyrmex apache. The above images are assorted views of the single individual collected on 1 November 2013. So far, I have been unable to find the colony of this interesting species.

Pseudomyrmex apache typically nests inside cavities of dead branches and abandoned galleries hollowed-out by beetles. According to Antweb.com: Pseudomyrmex apache is found throughout most of California except the mountains and extreme north. It occurs in chaparral, oak woodland, mixed (oak-pine-douglas fir) forest, coastal sage scrub, and desert riparian sites. Nests have been collected in dead branches of Arctostaphylos, Baccharis, Quercus and Umbellularia. There are also records from a Fraxinus gall and a Pinus attenuata cone. Workers appear to be generalist scavengers." My specimen was discovered in the coastal sage scrub of northern San Diego County (north side of Owens Peak) on a flowering Baccharis pilularis that resembles B. sarothroides. Dead branches of this common shrub often have hollow stems; however, I have yet to find the nest of this remarkable ant species.


Acacia Ant (Formicidae: Pseudomyrmecinae) Pseudomyrmex ferruginea

Tabove image shows three species of Acacia with swollen stipular spines that are hollowed out and occupied by symbiotic ants. Left: The bullhorn acacia (Acacia cornigera), a swollen-thorn acacia native to Mexico and Central America. In its native habitat, colonies of stinging ants (Pseudomyrmex ferruginea) occupy the hollowed-out thorns and fiercely defend the tree against ravaging insects, browsing mammals and epiphytic vines. In return, the host supplies its little guardian ants with protein-lipid Beltian bodies from its leaflet tips (yellowish granules in photo) and carbohydrate-rich nectar from glands on its petiole (just above the pair of spines). Center: Another Central American swollen thorn acacia (A. collinsii) with an acacia ant (P. ferruginea) sipping nectar from the petiolar nectary. Right: The African whistling thorn acacia (A. drepanolobium). The common name comes from the whistling sound that is produced when wind blows across the large hollowed-out thorns. Since the "thorns" on these trees are technically pairs of modified stipules, they are more correctly referred to as stipular spines.

Acacia ants (Pseudomyrmex ferruginea) guarding the branches and thorns (stipular spines) of Acacia collinsii in Santa Rosa National Park, Costa Rica. Touching the branch will cause the ants to quickly run onto your hand and sting viciously.

Swollen thorns (stipular spines) of the Central American Acacia collinsii. The hollow thorns house symbiotic stinging ants (Pseudomyrmex ferruginea) that protect the tree from browsing herbivores. Each thorn has an ant in its entrance hole. The above thorns contained residual ants for several days. Each time I handled a thorn an ant ran out and stung me.

See The Wayne's Word Article About Acacias
See Stipular Spines Of Swollen-Thorn Acacias
Necklace & Seed Doll Made Of Acacia Spines


Azteca Ant (Dolichoderinae) Azteca species

There are other trees in the Central American rain forest with symbiotic ants. Some of the most interesting are species of Cecropia of the mulberry family (Moraceae), including C. peltata and C. obtusifolia. Cecropia trees are easily recognized by their large, peltate, palmately lobed leaves which are clustered at the ends of relatively few, candelabra-like branches. In Costa Rica, the reason three-toed sloths are often found in cecropia trees is that they are easier to spot in the open, leafless branches compared with other trees. The pithy limbs and stem internodes are usually hollow and occupied by colonies of Azteca ants, a neotropical genus of aggressive, biting ants. The ants commonly feed on the nutritious "honeydew" secretions of mealy bugs, but will also forage for other insect prey. According to D. H. Janzen (Costa Rican Natural History, 1983), during the dry season in the Guanacaste Province of Costa Rica, leafless cecropia trees maintain a crop of tiny leaves bearing minute food bodies for the colonies of Azteca ants.

Azteca constructor living on Cecropia species in Costa Rica. Courtesy of Shannon Hartman 2012 www.antweb.org. Retrieved 14 May 2013. Right: Cecropica plant in Costa Rica with hollow internodes containing swarming a colony of biting Azteca ants.


Ant Plant & Symbiotic Iridomyrmex cordatus (Formicidae: Subfamily Dolichoderinae)

Ant plants (myrmecophytes) include several genera of epiphytes native to Southeast Asia, the Pacific region and northern Australia. They have swollen (caudiciform) stems covered with spines. Ant plants form a symbiotic relationship with ants and provide habitats for ant colonies high in the forest canopy, protecting them from the elements and also predators because of the spines. Hollow, smooth-walled tunnels and chambers develop inside the stems (caudices), living quarters for the ants. The tuberous stems even develop external entrance holes for the ant colonies, typically Iridomyrmex cordatus. [Argentine ants (Linepithema humile) were formerly placed in the genus Iridomyrmex.] The ants in turn provide defense for the plant and prevent tissue damage, swarming to defend their home if disturbed. The ant colonies also provide nutrients for the plants by leaving wastes within the tunnels inside the caudex. Special glands lining the tunnels then absorb nutrients for the plant. This symbiosis allows the plants to effectively gather nutrients (via the ants) from a much larger area than the roots ever could cover. The following two genera, Hydophytum and Myrmecodia (members of the coffee family Rubiaceae) were photographed at Huntington Botanical Garden.

An ant plant (Myrmecodia tuberosa)

An amazing "ant plant" (Hydnophytum) at Huntington Botanical Garden. Tunnels & chambers in the enlarged caudex provide living quarters for symbiotic ants which in turn provide the plant with nutrients & protection. The ant in photo is Iridomyrmex purpureus, not the typical symbiont for Hydnophytum, I. cordatus.


Tropical Leaf-Cutter Ant (Formicidae: Subfamily Myrmicinae: Tribe Attini)

Leaf-cutter ants (Atta sp.) crossing a trail along the Napo River, a tributary of the Amazon in Ecuador.

A nest of leaf-cutter ants (Atta cephalotes). The white area at the right side of image is a colony of fungal mycelia. Note the smaller worker ants and the large soldiers (white arrows).

  More Images Of The Arizona Leaf-Cutter Ant (Acromyrmex versicolor)  
More Images Of Tropical Leaf-Cutter Atta cephalotes At San Diego Zoo

The large winged leaf-cutter ant (Atta sexdens) from tropical America resembles a bee or wasp!

Any discussion of the diversity and natural history of fungi would be incomplete without mentioning the remarkable fungus-growing ants of the New World tropics. There are approximately 12 genera and 210 species of fungus-growing ants in the Attini tribe. Two of the genera, Atta and Acromyrmex are more commonly known as leaf-cutter ants. Leaf-cutter ants are an important forest herbivore because colonies containing millions of ants harvest leaves from a variety of plants for their subterranean gardens of basidiomycete mycelia. The leaves that are harvested by workers and laboriously carried to their nests are not eaten by the ants. Instead, the ants use the leaves as a substrate to grow fungus that they farm in special areas of their nests. The fungus provides the ant colony with a nutrient food source. Special enlarged mycelial structures called gongylida are rich in glycogen. The basiomycete for Atta cephalotes and Atta sexdens has been identified as Leucoagaricus gongylophorus = Leucocoprinus gongylophorus.

The ant colony is composed of several castes, including the queen, workers and large soldiers who often stand guard at the entrance of the nest, or even go on scouting missions to protect the colony from predators. Like the queen, the males are winged, and their only role is to inseminate the virgin queen. Workers include larger "media workers" who cut and carry leaf sections back to the nest, and "minima workers" who cut the leaves into minute pieces for the fungus garden. They also cover the leaf fragments with their antibacterial saliva which retards the growth of competing fungi, thus protecting their symbiotic fungus that is vital for their survival. They also feed the entire colony of ants.

Interestingly enough, fruiting bodies (basiocarps) of Leucoagaricus species can be found in urbanized areas of North America, including L. americanus and L. naucinus. The two latter fungi have also been listed in the genus Lepiota.


Edible Weaver Ants From Thailand
Subfamily Formicinae: Oecophylla

Wikipedia contains a good summary about weaver ants of the genus Oecophylla. Worker ants construct nests in trees by weaving together leaves using larval silk. Bending leaves and pulling them together requires a remarkable degree of coordination and cooperation between many workers. Workers are polymorphic with major and minors. Major workers are 8-10 mm long long, while queens are up to 16 mm, at least in my samples from Thailand. These arboreal ants have enormous colonies consisting of more than 100 nests spanning numerous trees and containing more than half a million workers. Workers and winged ants are collected by people in southeast Asia and eaten as a high-protein food supplement.

Bowl of crispy weaver ants (Oecophylla) from Thailand.

Weaver ants (Oecophylla) from Thailand: Mostly large winged queens.


Ants In 25 Million-Year-Old Dominican Republic Amber

These ants became entombed in the sticky resin of the extinct Hymenaea protera about 25 million years ago. The latter resinous tree was the ancestor of modern-day West Indian locusts (H. courbaril). Although a Dominicam Republic amber mine was depicted in the movie Jurassic Park, all the dinosaurs were extinct by 60 million years ago.

  The K-T Boundary Where Dinosours Became Extinct  

References:

  1. Evans, A.V. 2007. Field Guide to Insects and Spiders of North America. Sterling Publishing Co., Inc. New York, NY.    

  2. Hogue, C.L. 1993. Insects of the Los Angeles Basin. Natural History Museum of Los Angeles County.

  3. Hölldobler, B. and E.O. Wilson. 1990. The Ants. Harvard University Press, Cambridge, Massachusetts.

  4. Schmidt, J.O. 1986. "Chemistry, Pharmacology, and Chemical Ecology of Ant Venoms," pp. 425-508. In T. Piek [Ed.], Venoms of the Hymenoptera. Academic Press, London.

  5. Sorrells, Trevor R. 2011. "Chemical Defense by the Native Winter Ant (Prenolepis imparis) Against the Invasive
    Argentine Ant (Linepithema humile." PLOS ONE 6 (4): e18717. doi: 10.1371/journal pone.0018717

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