''Liometopum occidentale'', also called the velvety tree ant,PCT Online
/ref> is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Dolichoderinae Dolichoderinae is a subfamily of ants, which includes species such as the Argentine ant (''Linepithema humile''), the erratic ant, the odorous house ant, and the cone ant. The subfamily presents a great diversity of species throughout the wor ...

. ''Liometopum occidentale'' is often mistaken for

carpenter ant Carpenter ants (''Camponotus'' spp.) are a genus of large ants (workers ) indigenous to many parts of the world. True carpenter ants build nests inside wood, consisting of galleries chewed out with their mandibles or jaws, preferably in dead, ...

s (''Camponotus'' spp.) by homeowners and pest management professionals. This mistaken identity is due to morphological and behavioral characteristics they share with carpenter ants; namely polymorphic workers, a smooth convex thoracic profile, and the tendency to excavate wood. Consequently, their importance as structural pests may be greatly under reported, especially in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, and

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Taxonomy

''Liometopum occidentale'' was originally described as '' Liometopum microcephalum'' var. ''occidentale'' by . relocated it to a variety of '' Liometopum apiculatum''. It was finally elevated to the species level by and remained there in a recent taxonomic review by Del Toro et al. (2009).

Habitat

''Liometopum occidentale'' is found from sea level to over 1840 m in coastal regions from southern

to northern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. The range of elevation of this species also appears to depend on latitude with ants collected from locations in

as low as 7 m and up to 1700 m in

. They are the most common and dominant ant in

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

and

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

forests of southwestern U.S. They prefer to nest in the crevices of oaks,

alder Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...

elm Elms are deciduous and semi-deciduous trees comprising the genus ''Ulmus'' in the family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical- montane regions of North America and Eurasia, ...

s, cottonwoods, and

creosote Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood, or fossil fuel. They are typically used as preservatives or antiseptics. Some creosote types w ...

, in soil, underneath bark of dead trees.

Colonies

After finding no aggression between workers collected from significant distances apart and no territorial boundary, speculated that ''L. occidentale'' colonies are large and polydomous. Since they never found brood or

queens Queens is the largest by area of the Boroughs of New York City, five boroughs of New York City, coextensive with Queens County, in the U.S. state of New York (state), New York. Located near the western end of Long Island, it is bordered by the ...

, it is uncertain whether there are multiple queens within a nest, or whether each queen has some localized "sphere of exclusivity." and it just seems unlikely that there could be just one queen that produces enough eggs to establish a colony that is one kilometer wide, they also speculated that ''L. occidentale'' are

polygyne The gyne (, from Greek γυνή, "woman") is the primary reproductive female caste of social insects (especially ants, wasps, and bees of order Hymenoptera, as well as termites). Gynes are those destined to become queens, whereas female workers ...

. Colonies have been estimated to contain between 40,000 and 60,000 workers. Colony foundation of this species has not been studied as well as it has with the other two North American species.

Nests

''Liometopum occidentale'' typically nest in soil, crevices of trees, and under the bark of dead trees. However, were never found by leading to the speculation nests must lie deep under large boulders or among roots of large trees. To better understand the structure of their nests, more nests need to be excavated.

Feeding

''Liometopum occidentale'' are opportunistic omnivores and can often be found tending hemipterans and carrying prey insects back to the nest. They readily attend hemipterans and are found in

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

groves, but their role in disrupting biological control has not been determined. Their feeding preferences need to be studied to enable the development of an effective bait for pest control purposes.

Foraging activity

''Liometopum occidentale'' form massive foraging trails that extend 60 m or more from the nest, and can even be observed on hot days with temperatures between 24 and 38 °C. observed ''L. occidentale'' traveling mostly underground in very shallow galleries (1–2 cm deep), or in

leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituen ...

, however, we have also observed massive above ground trails. According to , ''L. occidentale'' in natural environments forage an areas as large as 2,000 m², but they only utilize between 486 and 1198 m² (740 m² average) of this area at any one time. This means that they are only using between 33 and 68% of this area, more than twice that of '' L. apiculatum''.

Reproduction

Nuptial flight Nuptial flight is an important phase in the reproduction of most ant, termite, and some bee species. It is also observed in some fly species, such as '' Rhamphomyia longicauda''. During the flight, virgin queens mate with males and then land ...

of ''L. occidentale'' reproductives have been observed throughout May. The annual productivity for a colony (40,000 to 60,000 workers) of this species is 2 to 2.8 kg of brood per year for 4–8 years. Workers housed without a queen will also lay unfertilized eggs that are eaten or develop into males.

References

* * * * * * * *

External links

* {{Taxonbar, from=Q3911844 Dolichoderinae Insects described in 1895 Hymenoptera of North America Edible insects