''Hyalella azteca'' is a widespread and abundant

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

amphipod Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

in North America. It reaches long, and is found in a range of fresh and brackish waters. It feeds on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesis, photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...

and diatoms and is a major food of waterfowl.

Description

''Hyalella azteca'' grows to a length of , with males being larger than females. Their colour is variable, but the most frequent hues are white, green and brown.

Distribution

''Hyalella azteca'' is found across

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. C ...

, the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean S ...

and North America, as far north as the Arctic tree line. It lives among vegetation in permanent bodies of freshwater, including lakes and rivers, extending into tidal fresh water, and freshwater barrier

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'' ...

s. It is "the most abundant amphipod of lakes n North America, with golf course ponds sometimes supporting large populations.

Ecology

In contrast to other species of ''

Hyalella ''Hyalella'' is a genus of amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more ...

'', ''H. azteca'' is extremely common and has wide ecological tolerances. It can tolerate

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of ...

waters and

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

s, but cannot tolerate a pH lower (more

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

ic) than 6.0. The main foodstuffs of ''H. azteca'' are

filamentous algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micro ...

and

diatom A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...

s, although they may also consume organic detritus. It cannot assimilate either

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

or lignin, even though these

biomolecule A biomolecule or biological molecule is a loosely used term for molecules present in organisms that are essential to one or more typically biological processes, such as cell division, morphogenesis, or development. Biomolecules include large ...

s are a major component of the

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 have fallen to the ground. This detritus or dead organic material and its constituent ...

. It can, however, assimilate 60%–90% of the bacterial biomass that it ingests. ''Hyalella azteca'' is an important food for many waterfowl. In Saskatchewan, 97% of the diet of female

white-winged scoter The white-winged scoter (''Melanitta deglandi'') is a large sea duck. The genus name is derived from Ancient Greek ''melas'' "black" and ''netta'' "duck". The species name commemorates French ornithologist Côme Damien Degland. Description The ...

s was observed to be ''H. azteca'', and it also makes up a significant part of the diet of lesser scaup.

Insecticide resistance

Some ''H. azteca'' have evolved

insecticide resistance Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens su ...

. This does however conflict with their need to adapt to climate change: Fulton et al 2021 finds some of their mechanisms of resistance impose a fitness cost under higher temperatures.

Life cycle

''Hyalella azteca'' passes through a minimum of nine instars during its development. Sexes can first be distinguished at the 6th instar, with the first mating occurring in the 8th instar. Subsequent instars, of which there may be 15–20, are considered adulthood.

Uses

''Hyalella azteca'' are used in various aquatic

bioassay A bioassay is an analytical method to determine the concentration or potency of a substance by its effect on living animals or plants (''in vivo''), or on living cells or tissues(''in vitro''). A bioassay can be either quantal or quantitative, dir ...

s (also called toxicity tests). Because of their wide distribution, ease of captive reproduction, and its niche in lake sediments, ''Hyalella azteca'' are used in aquatic toxicology assays in sediments Hyalella azteca have been used to test bioaccumulation of different contaminants such as manufactured nanomaterial

pesticide

and metal

https://doi.org/10.1016/j.envpol.2008.03.001]

Taxonomic history

''Hyalella azteca'' was first described by Henri Louis Frédéric de Saussure in 1858, under the name ''Amphitoe aztecus'', based on material collected by

Aztec The Aztecs () were a Mesoamerican culture that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl ...

s from a "cistern" near Veracruz, Mexico. It has also been described under several

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

s, including: *''Hyalella dentata'' S. I. Smith, 1874 *''Hyalella fluvialis'' Lockington, 1877 *''Hyalella inermis'' S. I. Smith, 1875 *''Hyalella knickerbockeri'' Bate, 1862 *''Hyalella ornata'' Pearse, 1911 When

Sidney Irving Smith Sidney Irving Smith (February 18, 1843 in Norway, Maine – May 6, 1926 in New Haven, Connecticut) was an American zoologist. Private life Sidney Smith was the son of Elliot Smith and Lavinia Barton. His brother in law was Addison Emery Verrill ...

erected the genus ''

'' in 1874, ''H. azteca'' was the only included species, and therefore the type species. The genus now includes dozens of species, mostly in South America. ''H. azteca'' is now thought to represent a species complex, since there is little

gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent a ...

between populations, and different

morphotype In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative '' phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the ...

s are known to coexist in some areas. Two local populations have been described as separate species – '' Hyalella texana'' from the

Edwards Plateau The Edwards Plateau is a geographic region at the crossroads of Central, South, and West Texas. It is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the Pecos River and Chihua ...

of Texas, and '' Hyalella montezuma'' from

Montezuma Well Montezuma Well ( yuf-x-yav, ʼHakthkyayva), a detached unit of Montezuma Castle National Monument, is a natural limestone sinkhole near the town of Lake Montezuma, Arizona, through which some of water emerge each day from an underground ...

, Arizona. In addition to being a species complex, laboratory work sequencing and analyzing the genome of lab populations of Hyalella azteca revealed Hyalella azteca shares characteristics of other model organisms. How these crustaceans interact with contaminants can provide insight about how other species will interact with those same contaminants.

Genome Sequencing Project

There is an ongoing ''Hyalella azteca'' genome sequencing project. This is part of a larger project being led by the Baylor college of Medicine Human Genome Sequencing Center (BCM-HGSC) ; in which 28 arthropod genomes are being sequenced. The sequencing of these genomes serves as a beginning to the larger i5k initiative, which has an end goal of sequencing 5,000 Arthropoda. Scientists looking to contribute to this research are able to nominate species to sequence, and download and share data to i5k website. Data can also be submitted to the Global Genome biodiversity workshop Biodiversity Repository.

References

1] "Aquatic Invertebrates: Amphipods". The Nature of the Rideau River. Canadian Museum of Nature. May 18, 2007. Retrieved October 5, 2010. Mark D. Sytsma; Jeffery R. Cordell; John W. Chapman; Robyn C. Draheim (October 2004). "Final Technical Report: Appendices" (PDF). Lower Columbia River Aquatic Nonindigenous Species Survey 2001–2004. United States Fish and Wildlife Service. Archived from the original (PDF) on June 4, 2010. Retrieved October 6, 2010. C. F. Mason (2002). "Acidification". Biology of Freshwater Pollution (4th ed.). Pearson Education. pp. 175–204. . Douglas Grant Smith (2001). "Amphipoda". Pennak's freshwater invertebrates of the United States: Porifera to Crustacea (4th ed.). John Wiley and Sons. pp. 569–584. . N. Kaushik (1975). "Decomposition of allochthonous organic matter and secondary production in stream ecosystems". Productivity of World Ecosystems: Proceedings of a Symposium Presented August 31–September 1, 1972, at the V General Assembly of the Special Committee for the International Biological Program, Seattle, Washington. United States National Academy of Sciences. pp. 90–95. . Gary L. Krapu; Kenneth J. Reinecke (1992). "Foraging ecology and nutrition". In Bruce D. J. Batt (ed.). Ecology and Management of Breeding Waterfowl. University of Minnesota Press. pp. 1–29. . Robert Jay Goldstein; Rodney W. Harper; Richard Edwards (2000). "Foods and feeding". American Aquarium Fishes. Volume 28 of W. L. Moody, Jr., natural history series. Texas A&M University Press. pp. 43–51. . Poynton, H. et al. (2018). The Toxicogenome of Hyalella azteca: A Model for Sediment Ecotoxicology and Evolutionary Toxicology. Environmental Science and Technology, 52(10), 6009–6022. https://doi.org/10.1021/acs.est.8b00837 Nebeker, A; Miller, C. "Use of the amphipod crustacean Hyalella azteca in freshwater and estuarine sediment toxicity tests". EPA Science Inventory. Environmental Protection Agency. Retrieved 22 August 2017. 0Kuehr, S et al. (2020). Testing the bioaccumulation potential of manufactured nanomaterials in the freshwater amphipod Hyalella azteca. Chemosphere 263(2021),1. https://doi.org/10.1016/j.chemosphere.2020.127961 1Fulton, C et al. (2020). Fitness costs of pesticide resistance in Hyalella azteca under future climate change scenarios. Science of the Total Environment, 753(2021), 1. https://doi.org/10.1016/j.scitotenv.2020.141945 2Couillard, Y et al. (2008). The amphipod Hyalella azteca as a biomonitor in field deployment studies for metal mining. Environmental Pollution, 156(2008), 1314–1324. https://doi.org/10.1016/j.envpol.2008.03.001 3Yihao Duan; Sheldon I. Guttman; James T. Oris; A. John Bailer (2000). "Genetic structure and relationships among populations of Hyalella azteca and H. montezuma (Crustacea:Amphipoda)". Journal of the North American Benthological Society. 19 (2): 308–320. doi:10.2307/1468073. JSTOR 1468073. 4Exequiel R. Gonzalez & Les Watling; Watling (2002). "Redescription of Hyalella azteca from its type locality, Vera Cruz, Mexico (Amphipoda: Hyalellidae)". Journal of Crustacean Biology. 22 (1): 173–183. doi:10.1651/0278-0372(2002)022 173:ROHAFI.0.CO;2. JSTOR 1549618. 5. Lowry (2010). J. Lowry (ed.). "Hyalella azteca (Saussure, 1858)". World Amphipoda