Hyalella azteca
Hyalella azteca is a widespread and abundant species of amphipod crustacean in North America. It reaches long, and is found in a range of fresh and brackish waters. It feeds on algae 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, the Caribbean 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 lagoons. It is "the most abundant amphipod of lakes [in North America]", with golf course ponds sometimes supporting large populations. Ecology. In contrast to other species of "Hyalella", "H. azteca" is extremely common and has wide ecological tolerances. It can tolerate alkaline waters and brackish waters, but cannot tolerate a pH lower (more acidic) than 6.0. The main foodstuffs of "H. azteca" are filamentous algae and diatoms, although they may also consume organic detritus. It cannot assimilate either cellulose or lignin, even though these biomolecules  are a major component of the leaf litter. 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 scoters 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. 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 bioassays., (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 nanomaterials , pesticides , and metals . 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 Aztecs from a "cistern" near Veracruz, Mexico. It has also been described under several junior synonyms, including: When Sidney Irving Smith erected the genus "Hyalella" 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 between populations, and different morphotypes are known to coexist in  some areas. Two local populations have been described as separate species – "Hyalella texana" from the Edwards Plateau of Texas, and "Hyalella montezuma" from Montezuma Well, 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. . [8 ] 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.  Kuehr, 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  Fulton, 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  Couillard, 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  Yihao 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.  Exequiel 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[0173:ROHAFI]2.0.CO;2. JSTOR  1549618. J. Lowry (2010). J. Lowry (ed.). "Hyalella azteca (Saussure, 1858)". World Amphipoda Further reading. Javidmehr A et al. (2015). 10- Day survival of Hyalella azteca as a function of water quality parameters. Ecotoxicology and Environmental Safety, 115(2015) 250–256. http://dx.doi.org/10.1016/j.ecoenv.2015.02.008 Fracácio, R et al. (2011). A comparative study of different diets to optimize cultivation of Hyalella azteca in the laboratory. Ecotoxicology and Environmental Safety, 74(2011), 1615–1618. https://doi.org/10.1016/j.ecoenv.2011.05.013 Sever, H et al. (2020). Recessivity of pyrethroid resistance and limited interspecies hybridization across Hyalella clades supports rapid and independent origins of resistance. Environmental Pollution, 266(2020).https://doi.org/10.1016/j.envpol.2020.115074 Christie, A et al. (2018). Prediction  of a peptidome for the ecotoxicological model Hyalella azteca( Creustacea; Amphipoda) using a de novo assembled transcriptome. Marine Genomics, 38(2018), 67–88. https://doi.org/10.1016/j.margen.2017.12.003 Pedersen, S et al. (2013). Pairing Behavior and reproduction in Hyalella azteca as sensitive endpoints for detecting long-term consequences of pesticide pulses. Aquatic Toxicology, 144-1445(2013), 59–65. https://dx.doi.org/10.1016/j.aquatox.2013.09.027