Pogonomyrmex californicus


Domain: Eukarya
Eukaryotes (for example, Alabama cave shrimp and popcorn flowers) have nuclei and membrane-bound organelles. Endosymbiotic theory states that their mitochondria arose from endosymbiosis with a bacterium. This idea is well supported in that all cells within eukaryotes have mitochondria with a remnant genome that is similar to heterotrophic gram-negative bacteria (characterized by cells that have two membranes and a cell wall in the space between the membranes).

Kingdom: Animalia
Animals such as the star-nosed mole and the giant silkworm caterpillar are multicellular and heterotrophic organisms that are motile and lack structural cells. Most animals exhibit bilateral symmetry and are triploblastic (have three types of tissues - the ectoderm that gave rise to skin and nervous tissue; the endoderm that gave rise to the digestive tract; and the mesoderm that gave rise to muscle, bone, and the circulatory system), though poriferans display asymmetry and have no true tissues, and cnidarians exhibit radial symmetry and are diploblastic (have two types of tissues - the ectoderm and the endoderm). Most animals also ingest food and digest it in an internal cavity (ADW 2014).

Phylum: Arthropoda
There are more species of arthropods, including the California night-stalking tiger beetle and the horse bot fly, than if one were to sum all other phyla (ADW 2014). They have strongly segmented bodies that allow for specialized body regions, or tagmata, that include the head, thorax, and abdomen (ADW 2014). Arthropods have exoskeletons made of chitin that provide an external covering for support, protection, and locomotion. They are protective in that they deter predators and are enhanced for camouflage. Arthropod exoskeletons do not grow with the organisms, so ecdysis, or molting, is required for growth. They have open circulatory systems that contain a heart, arteries, and the open spaces of the hemocoel (ADW 2014).

Class: Insecta
There are over one million named species of insects, like the devastating grasshopper; thus, they comprise a great majority of the earth's animal species (ADW 2014). They are located in many habitats, both terrestrial and freshwater. The shape and form of insects vary widely; however, no insect has a very large body size (ADW 2014). Insects have two pairs of wings that are formed from outgrowths of the body wall, which is quite unlike how any vertebrate wings are formed, as well as three pairs of walking legs (ADW 2014). Gases are carried to metabolizing tissues through spiracles - external openings - and finely-branched tubules (ADW 2014).

Order: Hymenoptera
The third largest order of insects, the Hymenoptera are ecological specialists that have thus had much success as a taxon; one representative of this order is the blue-black spider wasp (GE 2009). It is the only order besides the Isoptera, which includes the termites, that has evolved complex social systems in which there is a division of labor (GE 2009). Most of the Hymenoptera have two pairs of wings that operate together and are linked together by hooks called hamuli along the leading edge of the hind wings (GE 2009). Females in the Hymenoptera develop from fertilized eggs, while males develop from unfertilized eggs; whether or not an egg is fertilized is dependent on the females, who can thus regulate the sex ratio of offspring (GE 2009).

Family: Formicidae
Ants such as the black carpenter ant are placed in this single family (ADW 2014). Most formicids have a metapleural gland that produces phenylacetic acid that helps fight against problematic fungi and bacteria (ADW 2014). Ants are distinct from other insects in that they have a waist that is pinched down posteriorly at the abdomen (ADW 2014). Formicids have a complex social system similar to termites, bees, and wasps in that adult ants care for the young as a result of the coexistence of two or more generations, and castes are implemented in which there are reproductive queens and kings, and sterile workers (all female) (ADW 2014).

Genus: Pogonomyrmex
More than 70 species are contained within this genus (Pogolumina 2010). All of these ants are located solely in the western hemisphere from southern Canada to the southernmost tip of South America. All 25 species in North America, north of Mexico, are located west of the Mississippi River except for one species - P. badius (Pogolumina 2010). "Pogos," as the genus is often shortened to, are quite important in plant communities as a result of their acts of seed harvesting and seed dispersal (Pogolumina 2010). Many Pogos are quite aggressive, always prepared to sting to defend both the nest and themselves (Pogolumina 2010).

Species: Pogonomyrmex californicus (Named for the beard-like structure called the psammophore that is located below the head, as well as its prevalence in California [Pogolumina 2010].)
This ant within the genus Pogonomyrmex is primarily found in dry and arid desert regions in the United States and Mexico (De Vita 1979). It tends to forage individually, unlike many other ants within the same genus. This ant is well-known for its powerful sting; in fact, native peoples have used its venom as a hallucinogen (Groark 1996).

                    P. californicus domain and major clade phylogeny.
                        Figure 1. Domain and major clade phylogenetic tree.

The phylogenetic tree above displays the relative placement of Pogonomyrmex californicus within the major clades of the domain Eukarya (Figure 1; Campbell et al. 2008). The California harvester ant is a member of major clade Opisthokonta, just as the common dolphin is, because its sperm has posterior flagella, and its mitochondria contains flat cristae (folds in the inner membrane).

                              P. californicus kingdom and phylum phylogeny.
                                  Figure 2. Phyla of kingdom Animalia phylogenetic tree.

The phylogenetic tree above displays the relative placement of Pogonomyrmex californicus within the phyla of the kingdom Animalia (Figure 2; Campbell et al. 2008). The California harvester ant is a member of the phylum Arthropoda because it has tagmata and an exoskeleton made of chitin that provides an external covering for support, protection, and locomotion, as mentioned above (ADW 2014).

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