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132-799: See text Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States , as Canadian soldiers in the American Great Lakes region , and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order Ephemeroptera . This order is part of an ancient group of insects termed the Palaeoptera , which also contains dragonflies and damselflies . Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families . Mayflies have ancestral traits that were probably present in

264-514: A fin ). Many microscopic aquatic animals, and some larger but inactive ones, can absorb sufficient oxygen through the entire surface of their bodies, and so can respire adequately without gills. However, more complex or more active aquatic organisms usually require a gill or gills. Many invertebrates, and even amphibians, use both the body surface and gills for gaseous exchange. Gills usually consist of thin filaments of tissue , lamellae (plates), branches, or slender, tufted processes that have

396-443: A grasshopper , to jump into water and drown. Mayflies are involved in both primary production and bioturbation . A study in laboratory simulated streams revealed that the mayfly genus Centroptilum increased the export of periphyton , thus indirectly affecting primary production positively, which is an essential process for ecosystems. The mayfly can also reallocate and alter the nutrient availability in aquatic habitats through

528-627: A U.S. Army by Native Americans. The British demanded the establishment of a Native American barrier state at the Treaty of Ghent which ended the War of 1812 , but American negotiators rejected the idea because Britain had lost control of the region in the Battle of Lake Erie and the Battle of the Thames in 1813, where Tecumseh was killed by U.S. forces. The British then abandoned their Native American allies south of

660-411: A fish breathes, it draws in a mouthful of water at regular intervals. Then it draws the sides of its throat together, forcing the water through the gill openings, so it passes over the gills to the outside. Fish gill slits may be the evolutionary ancestors of the thymus glands , parathyroid glands , as well as many other structures derived from the embryonic branchial pouches . The gills of fish form

792-427: A great quantity of organic matter as nymphs and transfer a lot of phosphates and nitrates to terrestrial environments when they emerge from the water, thus helping to remove pollutants from aqueous systems. Along with caddisfly larvae and gastropod molluscs , the grazing of mayfly nymphs has a significant impact on the primary producers , the plants and algae, on the bed of streams and rivers. The nymphs are eaten by

924-532: A highly folded surface to increase surface area . The delicate nature of the gills is possible because the surrounding water provides support. The blood or other body fluid must be in intimate contact with the respiratory surface for ease of diffusion. A high surface area is crucial to the gas exchange of aquatic organisms, as water contains only a small fraction of the dissolved oxygen than air does, and it diffuses more slowly. A cubic meter of air contains about 275 grams of oxygen at STP . In fresh water ,

1056-455: A house, clearing the ground, and planting crops. A number of means facilitated the legal settlement of the territories in the Midwest: land speculation , federal public land auctions , bounty land grants in lieu of pay to military veterans, and, later, preemption rights for squatters. The "squatters" became "pioneers" and were increasingly able to purchase the lands on which they had settled for

1188-520: A large hatch was observed at midday in June. The soft-bodied subimagos are very attractive to predators. Synchronous emergence is probably an adaptive strategy that reduces the individual's risk of being eaten . The lifespan of an adult mayfly is very short, varying with the species. The primary function of the adult is reproduction; adults do not feed and have only vestigial mouthparts , while their digestive systems are filled with air. Dolania americana has

1320-421: A number of slits connecting the pharynx to the outside of the animal on either side of the fish behind the head. Originally there were many slits, but during evolution, the number reduced, and modern fish mostly have five pairs, and never more than eight. Sharks and rays typically have five pairs of gill slits that open directly to the outside of the body, though some more primitive sharks have six pairs with

1452-636: A scarcity of predacious nymphs can result in an over-abundance of their prey species. Fish that feed on mayfly nymphs that have bioaccumulated heavy metals are themselves at risk. Adult female mayflies find water by detecting the polarization of reflected light. They are easily fooled by other polished surfaces which can act as traps for swarming mayflies. The threat to mayflies applies also to their eggs. "Modest levels" of pollution in rivers in England are sufficient to kill 80% of mayfly eggs, which are as vulnerable to pollutants as other life-cycle stages; numbers of

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1584-480: A separate tube which has no respiratory tissue (the pharyngocutaneous duct) develops beneath the pharynx proper, expelling ingested debris by closing a valve at its anterior end. Lungfish larvae also have external gills , as does the primitive ray-finned fish Polypterus , though the latter has a structure different from amphibians. Tadpoles of amphibians have from three to five gill slits that do not contain actual gills. Usually no spiracle or true operculum

1716-421: A small mass of cells without any remaining gill-like structure. Marine teleosts also use their gills to excrete osmolytes (e.g. Na⁺, Cl ). The gills' large surface area tends to create a problem for fish that seek to regulate the osmolarity of their internal fluids. Seawater contains more osmolytes than the fish's internal fluids, so marine fishes naturally lose water through their gills via osmosis. To regain

1848-400: A subimago state into an adult stage and are sexually mature while appearing like a subimago with microtrichia on the wing membrane. Oligoneuriine mayflies form another exception in retaining microtrichia on their wings but not on their bodies. Subimagos are generally poor fliers, have shorter appendages, and typically lack the colour patterns used to attract mates. In males of Ephoron leukon ,

1980-534: A supernatural being who lived in the sky and was believed to have created the world and the Huron people. At death, Hurons thought the soul left the body to live in a village in the sky. Chippewas were a deeply religious people who believed in the Great Spirit. They worshiped the Great Spirit through all their seasonal activities, and viewed religion as a private matter: Each person's relation with his personal guardian spirit

2112-451: A thin film of atmospheric oxygen in an area with small openings called spiracles that connect to the tracheal system. The plastron typically consists of dense patches of hydrophobic setae on the body, which prevent water entry into the spiracles, but may also involve scales or microscopic ridges projecting from the cuticle. The physical properties of the interface between the trapped air film and surrounding water allow gas exchange through

2244-466: A third central caudal filament . The final moult of the nymph is not to the full adult form, but to a winged stage called a subimago that physically resembles the adult, but which is usually sexually immature and duller in colour. The subimago, or dun, often has partially cloudy wings fringed with minute hairs known as microtrichia; its eyes, legs and genitalia are not fully developed. Females of some mayflies (subfamily Palingeniinae) do not moult from

2376-451: A very short time and is known as a subimago, or to fly fishermen as a dun. Mayflies at the subimago stage are a favourite food of many fish, and many fishing flies are modelled to resemble them. The subimago stage does not survive for long, rarely for more than 24 hours. In some species, it may last for just a few minutes, while the mayflies in the family Palingeniidae have sexually mature subimagos and no true adult form at all. Often, all

2508-426: A wide range of predators and form an important part of the aquatic food chain . Fish are among the main predators, picking nymphs off the bottom or ingesting them in the water column, and feeding on emerging nymphs and adults on the water surface. Carnivorous stonefly , caddisfly , alderfly and dragonfly larvae feed on bottom-dwelling mayfly nymphs, as do aquatic beetles, leeches, crayfish and amphibians . Besides

2640-538: A written form of language. In the 16th century, the natives of the area used projectiles and tools of stone, bone, and wood to hunt and farm. They made canoes for fishing. Most of them lived in oval or conical wigwams that could be easily moved away. Various tribes had different ways of living. The Ojibwas were primarily hunters and fishing was also important in the Ojibwas economy. Other tribes such as Sac, Fox, and Miami, both hunted and farmed. They were oriented toward

2772-883: Is Heartland . Among the Native Americans , Paleo-Americans cultures were the earliest in North America, with a presence in the Great Plains and Great Lakes areas from about 12,000 BCE to around 8,000 BCE. Following the Paleo-American period is the Archaic period (8,000 BCE to 1,000 BCE), the Woodland Tradition (1,000 BCE to 100 CE), and the Mississippian Period (900 to 1500 CE). Archeological evidence indicates that Mississippian culture traits probably began in

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2904-428: Is a tendency for the eggs and nymphs to get washed downstream. To counteract this, females may fly upriver before depositing their eggs. For example, the female Tisza mayfly , the largest European species with a length of 12 cm (4.7 in), flies up to 3 kilometres (2 mi) upstream before depositing eggs on the water surface. These sink to the bottom and hatch after 45 days, the nymphs burrowing their way into

3036-627: Is present, though many species have operculum-like structures. Instead of internal gills, they develop three feathery external gills that grow from the outer surface of the gill arches. Sometimes, adults retain these, but they usually disappear at metamorphosis . Examples of salamanders that retain their external gills upon reaching adulthood are the olm and the mudpuppy . Still, some extinct tetrapod groups did retain true gills. A study on Archegosaurus demonstrates that it had internal gills like true fish. Crustaceans , molluscs , and some aquatic insects have tufted gills or plate-like structures on

3168-405: Is renewed through the gills. In the larval dragonfly , the wall of the caudal end of the alimentary tract ( rectum ) is richly supplied with tracheae as a rectal gill, and water pumped into and out of the rectum provides oxygen to the closed tracheae. A plastron is a type of structural adaptation occurring among some aquatic arthropods (primarily insects), a form of inorganic gill which holds

3300-569: Is represented in the fossil record by the Ypresian species N. antiqua from Washington state . Grimaldi and Engel, reviewing the phylogeny in 2005, commented that many cladistic studies had been made with no stability in Ephemeroptera suborders and infraorders; the traditional division into Schistonota and Pannota was wrong because Pannota is derived from the Schistonota. The phylogeny of

3432-506: Is the area between the historical foreground of European invasion and occupation and the background of Indian defeat and retreat. White specifically designates "the lands bordering the rivers flowing into the northern Great Lakes and the lands south of the lakes to the Ohio" as the location of the middle ground. This includes the modern Midwestern states of Ohio, Indiana, Illinois, Wisconsin, and Michigan as well as parts of Canada. The middle ground

3564-741: The Algonquian language family. Some tribes—such as the Stockbridge-Munsee and the Brothertown —are also Algonkian-speaking tribes who relocated from the eastern seaboard to the Great Lakes region in the 19th century. The Oneida belong to the Iroquois language group and the Ho-Chunk of Wisconsin are one of the few Great Lakes tribes to speak a Siouan language. American Indians in this area did not develop

3696-522: The Arikara , Hidatsa , Iowa , Kaw (or Kansa) , Kitsai , Mandan , Missouria , Nez Perce , Omaha , Osage , Otoe , Pawnee , Ponca , Quapaw , Santee , Wichita , and Yankton . The nomadic tribes of the Great Plains survived on hunting ; some of their major hunts centered on deer and buffalo. Some tribes are described as part of the "Buffalo Culture" (sometimes called, for the American bison ). Although

3828-481: The Blackfoot , Arapaho , Assiniboine , Cheyenne , Comanche , Crow , Gros Ventre , Kiowa , Lakota , Lipan , Plains Apache (or Kiowa Apache), Plains Cree , Plains Ojibwe , Sarsi , Shoshone , Stoney , and Tonkawa . The second group of Plains Indians (sometimes referred to as Prairie Indians) were the semi-sedentary tribes who, in addition to hunting buffalo, lived in villages and raised crops. These included

3960-456: The Broadnose sevengill shark being the only cartilaginous fish exceeding this number. Adjacent slits are separated by a cartilaginous gill arch from which projects a cartilaginous gill ray . This gill ray is the support for the sheet-like interbranchial septum , which the individual lamellae of the gills lie on either side of. The base of the arch may also support gill rakers , projections into

4092-1032: The Great Plains region. Chicago is the most populous city in the American Midwest and the third-most populous in the United States. Chicago and its suburbs , colloquially known as Chicagoland , form the largest metropolitan area with 10 million people, making it the fourth-largest metropolitan area in North America , after Greater Mexico City , the New York metropolitan area , and Greater Los Angeles . Other large Midwestern cities include Columbus , Indianapolis , Detroit , Milwaukee , Kansas City , Omaha , Minneapolis , Wichita , Cleveland , Cincinnati , St. Paul , St. Louis , and Des Moines . Large midwestern metropolitan areas include Metro Detroit , Minneapolis–St. Paul , Greater St. Louis , Greater Cincinnati ,

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4224-622: The Haitian Revolution and together with the fact that France could not effectively defend Louisiana from a possible British attack, he sold the territory to the United States in the Louisiana Purchase of 1803. Meanwhile, the British maintained forts and trading posts in U.S. territory, refusing to give them up until 1796 by the Jay Treaty . American settlement began either via routes over

4356-589: The Holarctic has a smaller number of genera but a high degree of speciation. Some thirteen families are restricted to a single bioregion . The main families have some general habitat preferences: the Baetidae favour warm water; the Heptageniidae live under stones and prefer fast-flowing water; and the relatively large Ephemeridae make burrows in sandy lake or river beds. The nymph is the dominant life history stage of

4488-538: The Kansas City metro area , the Columbus metro area , and Greater Cleveland . The region's economy is a mix of heavy industry and agriculture, with extensive areas forming part of the United States' Corn Belt . Finance and services such as medicine and education are becoming increasingly important. Its central location makes it a transportation crossroads for river boats, railroads, autos, trucks, and airplanes. Politically,

4620-564: The Louisiana Purchase , and establish trade and U.S. sovereignty over the native peoples along the Missouri River . The Lewis and Clark Expedition established relations with more than two dozen indigenous nations west of the Missouri River. The Expedition returned east to St. Louis in the spring of 1806. The Midwest has been a key swing district in national elections, with highly contested elections in closely divided states often deciding

4752-474: The Lower Cretaceous Crato Formation of Brazil also belongs as the last offshoot to Permoplectoptera. The Crato outcrops otherwise yielded fossil specimens of modern mayfly families or the extinct (but modern) family Hexagenitidae. However, from the same locality the strange larvae and adults of the extinct family Mickoleitiidae (order Coxoplectoptera ) have been described, which represents

4884-721: The Saint Lawrence River by Jacques Cartier in 1534 and ending with their cessation of the majority of their holdings in North America to the Kingdom of Great Britain in the Treaty of Paris (1763) . In 1673 the Governor of New France sent Jacques Marquette , a Catholic priest and missionary, and Louis Jolliet , a fur trader , to map the way to the Northwest Passage to the Pacific. They traveled through Michigan's upper peninsula to

5016-752: The St. Louis, Missouri area and spread northwest along the Mississippi and Illinois rivers and entered the state along the Kankakee River system. It also spread northward into Indiana along the Wabash , Tippecanoe , and White Rivers. Mississippian peoples in the Midwest were mostly farmers who followed the rich, flat floodplains of Midwestern rivers. They brought with them a well-developed agricultural complex based on three major crops— maize , beans , and squash . Maize, or corn,

5148-457: The Treaty of Paris , Spain was given Louisiana ; the area west of the Mississippi. St. Louis and Ste. Genevieve in Missouri were the main towns, but there was little new settlement. France regained Louisiana from Spain in exchange for Tuscany by the terms of the Treaty of San Ildefonso in 1800. Napoleon had lost interest in re-establishing a French colonial empire in North America following

5280-411: The blue-winged olive mayfly ( Baetis ) have fallen dramatically, almost to none in some rivers. The major pollutants thought to be responsible are fine sediment and phosphate from agriculture and sewage. The status of many species of mayflies is unknown because they are known from only the original collection data. Four North American species are believed to be extinct. Among these, Pentagenia robusta

5412-413: The exuviae (cast skin) and then flies upwards, and in some, the nymph climbs out of the water before transforming. Nymphs live primarily in streams under rocks, in decaying vegetation or in sediments. Few species live in lakes, but they are among the most prolific. For example, the emergence of one species of Hexagenia was recorded on Doppler weather radar by the shoreline of Lake Erie in 2003. In

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5544-520: The imago . Mayflies "hatch" (emerge as adults) from spring to autumn, not necessarily in May, in enormous numbers. Some hatches attract tourists. Fly fishermen make use of mayfly hatches by choosing artificial fishing flies that resemble them. One of the most famous English mayflies is Rhithrogena germanica , the fisherman's "March brown mayfly". The brief lives of mayfly adults have been noted by naturalists and encyclopaedists since Aristotle and Pliny

5676-434: The mesothorax and metathorax , being fused. Each segment bears a pair of legs which usually terminate in a single claw. The legs are robust and often clad in bristles, hairs or spines. Wing pads develop on the mesothorax, and in some species, hindwing pads develop on the metathorax. The abdomen consists of ten segments, some of which may be obscured by a large pair of operculate gills, a thoracic shield (expanded part of

5808-403: The prothorax ) or the developing wing pads. In most taxa up to seven pairs of gills arise from the top or sides of the abdomen, but in some species they are under the abdomen, and in a very few species the gills are instead located on the coxae of the legs, or the bases of the maxillae. The abdomen terminates in slender thread-like projections, consisting of a pair of cerci , with or without

5940-449: The spiracles on the abdomen don't have closing muscles. Uniquely among insects, mayflies possess paired genitalia, with the male having two aedeagi (penis-like organs) and the female two gonopores (sexual openings). Mayflies are hemimetabolous (they have "incomplete metamorphosis "). They are unique among insects in that they moult one more time after acquiring functional wings; this last-but-one winged ( alate ) instar usually lives

6072-492: The thorax , which bears the forewings, is enlarged to hold the main flight muscles. Adults have short, flexible antennae, large compound eyes, three ocelli and non-functional mouthparts. In most species, the males' eyes are large and the front legs unusually long, for use in locating and grasping females during the mid-air mating. In the males of some families, there are two large cylindrical "turban" eyes (also known as turbanate or turbinate eyes) that face upwards in addition to

6204-710: The Appalachian Mountains or through the waterways of the Great Lakes. Fort Pitt (now Pittsburgh ) at the source of the Ohio River became the main base for settlers moving into the Midwest. Marietta, Ohio in 1787 became the first settlement in Ohio, but not until the defeat of Native American tribes at the Battle of Fallen Timbers in 1794 was large-scale settlement possible. Large numbers also came north from Kentucky into southern Ohio, Indiana and Illinois. The region's fertile soil produced corn and vegetables; most farmers were self-sufficient. They cut trees and claimed

6336-622: The Elder in classical antiquity . The German engraver Albrecht Dürer included a mayfly in his 1495 engraving The Holy Family with the Mayfly to suggest a link between heaven and earth. The English poet George Crabbe compared the brief life of a daily newspaper with that of a mayfly in the satirical poem "The Newspaper" (1785), both being known as "ephemera". Immature mayflies are aquatic and are referred to as nymphs or naiads. In contrast to their short lives as adults, they may live for several years in

6468-615: The Endeavors of Government, or Fear of Indians has kept them properly within Bounds." The British had a long-standing goal of establishing a Native American buffer state in the American Midwest to resist American westward expansion. With victory in the American Revolution the new government considered evicting the squatters from areas that were now federally owned public lands. In 1785, soldiers under General Josiah Harmar were sent into

6600-645: The Ephemeroptera was first studied using molecular analysis by Ogden and Whiting in 2005. They recovered the Baetidae as sister to the other clades. Mayfly phylogeny was further studied using morphological and molecular analyses by Ogden and others in 2009. They found that the Asian genus Siphluriscus was sister to all other mayflies. Some existing lineages such as Ephemeroidea , and families such as Ameletopsidae, were found not to be monophyletic , through convergence among nymphal features. The following traditional classification, with two suborders Pannota and Schistonota ,

6732-577: The French and British, conflicts and treaties with the United States both during the Revolutionary War and after , and its ultimate clearing/erasure throughout the nineteenth century. European settlement of the area began in the 17th century following French exploration of the region and became known as New France , including the Illinois Country . The French period began with the exploration of

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6864-534: The French and the British into competition with each other to their own benefit. The Indian demand for certain kinds of cloth in particular fueled this competition. This, however, changed following the Seven Years' War with Britain's victory over France and the cession of New France to Great Britain. The British attempted to establish a more assertive relationship with the Indians of the pays d'en haut , eliminating

6996-856: The Midwest or the American Midwest ) is one of the four census regions defined by the United States Census Bureau . It occupies the northern central part of the United States . It was officially named the North Central Region by the U.S. Census Bureau until 1984. It is between the Northeastern United States and the Western United States , with Canada to the north and the Southern United States to

7128-469: The Ohio country to destroy the crops and burn down the homes of any squatters they found living there. But overall the federal policy was to move Indians to western lands (such as the Indian Territory in modern Oklahoma) and allow a very large numbers of farmers to replace a small number of hunters. Congress repeatedly debated how to legalize settlements. On the one hand, Whigs such as Henry Clay wanted

7260-527: The Plains Indians hunted other animals, such as elk or antelope , bison was their primary game food source. Bison flesh, hide, and bones from bison hunting provided the chief source of raw materials for items that Plains Indians made, including food, cups, decorations, crafting tools, knives, and clothing. The tribes followed the bison's seasonal grazing and migration. The Plains Indians lived in teepees because they were easily disassembled and allowed

7392-445: The abdomen tilted upwards. Females fly into these swarms, and mating takes place in the air. A rising male clasps the thorax of a female from below using his front legs bent upwards, and inseminates her. Copulation may last just a few seconds, but occasionally a pair remains in tandem and flutters to the ground. Males may spend the night in vegetation and return to their dance the following day. Although they do not feed, some briefly touch

7524-718: The alliance it created. In the meshed French and Algonquian system of trade, the Algonquian familial metaphor of a father and his children shaped the political relationship between the French and the Natives in this region. The French, regarded as the metaphoric father, were expected to provide for the needs of the Algonquians and, in return, the Algonquians, the metaphoric children, would be obligated to assist and obey them. Traders coming into Indian villages facilitated this system of symbolic exchange to establish or maintain alliances and friendships. Marriage also became an important aspect of

7656-453: The beating of cilia or other appendages, or by means of a pumping mechanism. In fish and some molluscs, the efficiency of the gills is greatly enhanced by a countercurrent exchange mechanism in which the water passes over the gills in the opposite direction to the flow of blood through them. This mechanism is very efficient and as much as 90% of the dissolved oxygen in the water may be recovered. The gills of vertebrates typically develop in

7788-525: The conflict, the British government was forced to compromise and loosely re-created a trade system that was an echo of the French one. While French control ended in 1763 after their defeat in the Seven Years' War, most of the several hundred French settlers in small villages along the Mississippi River and its tributaries remained, and were not disturbed by the new British administration. By the terms of

7920-527: The direct mortality caused by these predators, the behaviour of their potential prey is also affected, with the nymphs' growth rate being slowed by the need to hide rather than feed. The nymphs are highly susceptible to pollution and can be useful in the biomonitoring of water bodies. Once they have emerged, large numbers are preyed on by birds, bats and by other insects, such as Rhamphomyia longicauda . Mayfly nymphs may serve as hosts for parasites such as nematodes and trematodes . Some of these affect

8052-417: The dissolved oxygen content is approximately 8 cm /L compared to that of air which is 210 cm /L. Water is 777 times more dense than air and is 100 times more viscous. Oxygen has a diffusion rate in air 10,000 times greater than in water. The use of sac-like lungs to remove oxygen from water would not be efficient enough to sustain life. Rather than using lungs, "[g]aseous exchange takes place across

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8184-447: The dissolved oxygen when they are on land. Galen observed that fish had multitudes of openings ( foramina ), big enough to admit gases, but too fine to give passage to water. Pliny the Elder held that fish respired by their gills, but observed that Aristotle was of another opinion. The word branchia comes from the Greek βράγχια , "gills", plural of βράγχιον (in singular, meaning

8316-501: The female line, while the others favored the patrilineal method. All tribes were governed under chiefdoms or complex chiefdoms. For example, Hurons were divided into matrilineal clans, each represented by a chief in the town council, where they met with a town chief on civic matters. But Chippewa people's social and political life was simpler than that of settled tribes. The religious beliefs varied among tribes. Hurons believed in Yoscaha ,

8448-913: The female submerges and places the eggs among plants or in crevices underwater, but in general, they sink to the bottom. The incubation time is variable, depending at least in part on temperature, and may be anything from a few days to nearly a year. Eggs can go into a quiet dormant phase or diapause . The larval growth rate is also temperature-dependent, as is the number of moults . At anywhere between ten and fifty, these post-embryonic moults are more numerous in mayflies than in most other insect orders. The nymphal stage of mayflies may last from several months to several years, depending on species and environmental conditions. Around half of all mayfly species whose reproductive biology has been described are parthenogenetic (able to asexually reproduce), including both partially and exclusively parthenogenetic populations and species. Many species breed in moving water, where there

8580-421: The first flying insects, such as long tails and wings that do not fold flat over the abdomen . Their immature stages are aquatic fresh water forms (called "naiads" or " nymphs "), whose presence indicates a clean, unpolluted and highly oxygenated aquatic environment. They are unique among insect orders in having a fully winged terrestrial preadult stage, the subimago, which moults into a sexually mature adult,

8712-410: The first flying insects. These include long tails and wings that do not fold flat over the abdomen. Mayflies are delicate-looking insects with one or two pairs of membranous, triangular wings, which are extensively covered with veins . At rest, the wings are held upright, like those of a butterfly . The hind wings are much smaller than the forewings and may be vestigial or absent. The second segment of

8844-481: The food chain. Mayflies are distributed all over the world in clean freshwater habitats, though absent from Antarctica. They tend to be absent from oceanic islands or represented by one or two species that have dispersed from nearby mainland. Female mayflies may be dispersed by wind, and eggs may be transferred by adhesion to the legs of waterbirds. The greatest generic diversity is found in the Neotropical realm , while

8976-571: The fossil sister group of modern mayflies, even though they had very peculiar adaptations such as raptorial forelegs. The oldest mayfly inclusion in amber is Cretoneta zherichini (Leptophlebiidae) from the Lower Cretaceous of Siberia . In the much younger Baltic amber numerous inclusions of several modern families of mayflies have been found (Ephemeridae, Potamanthidae, Leptophlebiidae, Ametropodidae, Siphlonuridae, Isonychiidae, Heptageniidae, and Ephemerellidae). The modern genus Neoephemera

9108-417: The genus Isonychia . The nymph have forelegs that contain long bristle-like structures that have two rows of hairs. Interlocking hairs form the filter by which the insect traps food particles. The action of filter feeding has a small impact on water purification but an even larger impact on the convergence of small particulate matter into matter of a more complex form that goes on to benefit consumers later in

9240-411: The gills are contained in spherical pouches, with a circular opening to the outside. Like the gill slits of higher fish, each pouch contains two gills. In some cases, the openings may be fused together, effectively forming an operculum. Lampreys have seven pairs of pouches, while hagfishes may have six to fourteen, depending on the species. In the hagfish, the pouches connect with the pharynx internally and

9372-567: The global climate change of the Little Ice Age . Their culture effectively ended before 1492. The major tribes of the Great Lakes region included the Huron , Ottawa , Ojibwe , Potawatomi , Ho-Chunk , Menominee , Sauk , Meskwaki , Neutrals , and the Miami . Most numerous were the Huron and Ho-Chunk. Fighting and battle were often launched between tribes, with the losers forced to flee. Most are of

9504-613: The government to get maximum revenue and also wanted stable middle-class law-abiding settlements of the sort that supported towns (and bankers). Jacksonian Democrats such as Thomas Hart Benton wanted the support of poor farmers, who reproduced rapidly, had little cash, and were eager to acquire cheap land in the West. Democrats did not want a big government, and keeping revenues low helped that cause. Democrats avoided words like "squatter" and regarded "actual settlers" as those who gained title to land, settled on it, and then improved upon it by building

9636-461: The growing influence of women in the fur trade also came the increasing demand of cloth which very quickly grew to be the most desired trade good. English traders entered the Ohio country as a serious competitor to the French in the fur trade around the 1690s. English (and later British) traders almost consistently offered the Indians better goods and better rates than the French, with the Indians being able to play that to their advantage, thrusting

9768-543: The individuals in a population mature at once (a hatch), and for a day or two in the spring or autumn, mayflies are extremely abundant, dancing around each other in large groups, or resting on every available surface. In many species the emergence is synchronised with dawn or dusk, and light intensity seems to be an important cue for emergence, but other factors may also be involved. Baetis intercalaris , for example, usually emerges just after sunset in July and August, but in one year,

9900-492: The insect can become oxygen-depleted if there is no water movement, so many such insects in still water actively direct a flow of water over their bodies. The inorganic gill mechanism allows aquatic arthropods with plastrons to remain constantly submerged. Examples include many beetles in the family Elmidae , aquatic weevils , and true bugs in the family Aphelocheiridae , as well as at least one species of ricinuleid arachnid and various mites. A somewhat similar mechanism

10032-509: The lakes. The Native Americans ended being the main losers in the War of 1812 . Apart from the short Black Hawk War of 1832, the days of Native American warfare east of the Mississippi River had ended. In 1803, President Thomas Jefferson commissioned the Lewis and Clark Expedition that took place between May 1804 and September 1806. Launching from Camp Dubois in Illinois, the goal was to explore

10164-641: The land, then sold it to newcomers and then moved further west to repeat the process. Settlers without legal claims, called "squatters", had been moving into the Midwest for years before 1776. They pushed further and further down the Ohio River during the 1760s and 1770s and sometimes engaged in conflict with the Native Americans. British officials were outraged. These squatters were characterized by British General Thomas Gage as "too Numerous, too Lawless, and Licentious ever to be restrained", and regarded them as "almost out of Reach of Law and government; Neither

10296-814: The large blue lake mayfly, which is a native of Australia and is listed as endangered because its alpine habitat is vulnerable to climate change . Ephemeroptera was defined by Alpheus Hyatt and Jennie Maria Arms Sheldon in 1890–1. The taxonomy of the Ephemeroptera was reworked by George F. Edmunds and Jay R Traver , starting in 1954. Traver contributed to the 1935 work The Biology of Mayflies , and has been called "the first Ephemeroptera specialist in North America". As of 2012, over 3,000 species of mayfly in 42 families and over 400 genera are known worldwide, including about 630 species in North America . Mayflies are an ancient group of winged (pterygote) insects. Putative fossil stem group representatives (e.g. Syntonopteroidea-like Lithoneura lameerrei ) are already known from

10428-535: The late Carboniferous . The name Ephemeroptera is from the Greek ἐφήμερος, ephemeros "short-lived" (literally "lasting a day", cf. English " ephemeral "), and πτερόν, pteron , " wing ", referring to the brief lifespan of adults. The English common name is for the insect's emergence in or around the month of May in the UK. The name shadfly is from the Atlantic fish the shad , which runs up American East Coast rivers at

10560-409: The lateral eyes. They are capable of detecting ultraviolet light and are thought to be used during courtship to detect females flying above them. In some species all the legs are functionless, apart from the front pair in males. The abdomen is long and roughly cylindrical, with ten segments and two or three long cerci (tail-like appendages) at the tip. Like Entognatha , Archaeognatha and Zygentoma ,

10692-453: The location of Native American settlements near the headwaters of the Wabash River , but on November 4 they were routed in battle by a tribal confederation led by Miami Chief Little Turtle and Shawnee chief Blue Jacket . More than 600 soldiers and scores of women and children were killed in the battle, which has since borne the name " St. Clair's Defeat ". It remains the greatest defeat of

10824-502: The mayfly. Different insect species vary in their tolerance to water pollution, but in general, the larval stages of mayflies, stoneflies (Plecoptera) and caddis flies (Trichoptera) are susceptible to a number of pollutants including sewage , pesticides and industrial effluent . In general, mayflies are particularly sensitive to acidification , but tolerances vary, and certain species are exceptionally tolerant to heavy metal contamination and to low pH levels. Ephemerellidae are among

10956-611: The middle ground was introduced in Richard White's seminal work: The Middle Ground: Indians, Empires, and Republics in the Great Lakes Region, 1650–1815 originally published in 1991. White defines the middle ground like so: The middle ground is the place in between cultures, peoples, and in between empires and the non state world of villages. It is a place where many of the North American subjects and allies of empires lived. It

11088-558: The minimum price thanks to various preemption acts and laws passed throughout the 1810s-1840s. In Washington, Jacksonian Democrats favored squatter rights while banker-oriented Whigs were opposed; the Democrats prevailed. In 1791, General Arthur St. Clair became commander of the United States Army and led a punitive expedition with two Regular Army regiments and some militia. Near modern-day Fort Recovery , his force advanced to

11220-717: The most powerful and dominant tribes were the Dakota or Sioux , who occupied large amounts of territory in the Great Plains of the Midwest. The area of the Great Sioux Nation spread throughout the South and Midwest, up into the areas of Minnesota and stretching out west into the Rocky Mountains. At the same time, they occupied the heart of prime buffalo range, and also an excellent region for furs they could sell to French and American traders for goods such as guns. The Sioux (Dakota) became

11352-593: The most powerful of the Plains tribes and the greatest threat to American expansion. The Sioux comprise three major divisions based on Siouan dialect and subculture: Today, the Sioux maintain many separate tribal governments scattered across several reservations, communities, and reserves in the Dakotas, Nebraska, Minnesota, and Montana in the United States, as well as Manitoba and southern Saskatchewan in Canada. The theory of

11484-436: The most tolerant groups and Siphlonuridae and Caenidae the least. The adverse effects on the insects of pollution may be either lethal or sub-lethal, in the latter case resulting in altered enzyme function, poor growth, changed behaviour or lack of reproductive success. As important parts of the food chain, pollution can cause knock-on effects to other organisms; a dearth of herbivorous nymphs can cause overgrowth of algae, and

11616-429: The mouth and over the gills by rapidly swimming forward. In slow-moving or bottom-dwelling species, especially among skates and rays, the spiracle may be enlarged, and the fish breathes by sucking water through this opening, instead of through the mouth. Chimaeras differ from other cartilagenous fish, having lost both the spiracle and the fifth gill slit. The remaining slits are covered by an operculum , developed from

11748-406: The mouth at the front. There are two large compound eyes , three ocelli (simple eyes) and a pair of antennae of variable lengths, set between or in front of the eyes. The mouthparts are designed for chewing and consist of a flap-like labrum , a pair of strong mandibles , a pair of maxillae , a membranous hypopharynx and a labium . The thorax consists of three segments – the hindmost two,

11880-479: The mouth by the beating of cilia. Respiration in the echinoderms (such as starfish and sea urchins ) is carried out using a very primitive version of gills called papulae . These thin protuberances on the surface of the body contain diverticula of the water vascular system . The gills of aquatic insects are tracheal , but the air tubes are sealed, commonly connected to thin external plates or tufted structures that allow diffusion. The oxygen in these tubes

12012-419: The mouth keep the water from escaping. The gill arches of bony fish typically have no septum, so the gills alone project from the arch, supported by individual gill rays. Some species retain gill rakers. Though all but the most primitive bony fish lack spiracles, the pseudobranch associated with them often remains, being located at the base of the operculum. This is, however, often greatly reduced, consisting of

12144-533: The national result. From 1860 to 1920, both parties tried to find their presidential and vice presidential candidates from the region. One of the two major political parties in the United States, the Republican Party , originated in the Midwest in the 1850s; Ripon, Wisconsin , had the first local meeting while Jackson, Michigan , had the first statewide meeting of the new party. Its membership included many Yankees out of New England and New York who had settled

12276-410: The native peoples who lived along the route were generally friendly, and that the natural resources of the lands in between were extraordinary. New France officials led by LaSalle followed up and erected a 4,000-mile (6,400 km) network of fur trading posts. The fur trade was an integral part of early European and Indian relations. It was the foundation upon which their interactions were built and

12408-434: The nomadic life of following game. When Spanish horses were obtained, the Plains tribes rapidly integrated them into their daily lives. By the early 18th century, many tribes had fully adopted a horse culture . Before their adoption of guns, the Plains Indians hunted with spears , bows , and bows and arrows , and various forms of clubs . The use of horses by the Plains Indians made hunting (and warfare) much easier. Among

12540-506: The northern tip of Lake Michigan. On canoes, they crossed the massive lake and landed at present-day Green Bay, Wisconsin . They entered the Mississippi River on 17 June 1673. Marquette and Jolliet were the first to map the northern portion of the Mississippi River. They confirmed that it was easy to travel from the St. Lawrence River through the Great Lakes all the way to the Gulf of Mexico by water, that

12672-477: The nymphs are herbivores or detritivores , feeding on algae , diatoms or detritus , but in a few species, they are predators of chironomid and other small insect larvae and nymphs. Nymphs of Povilla burrow into submerged wood and can be a problem for boat owners in Asia. Some are able to shift from one feeding group to another as they grow, thus enabling them to utilise a variety of food resources. They process

12804-437: The nymphs of most mayfly species, the paddle-like gills do not function as respiratory surfaces because sufficient oxygen is absorbed through the integument, instead serving to create a respiratory current. However, in low-oxygen environments such as the mud at the bottom of ponds in which Ephemera vulgata burrows, the filamentous gills act as true accessory respiratory organs and are used in gaseous exchange. In most species,

12936-423: The nymphs' behaviour in such a way that they become more likely to be predated. Other nematodes turn adult male mayflies into quasi-females which haunt the edges of streams, enabling the parasites to break their way out into the aqueous environment they need to complete their life cycles. The nymphs can also serve as intermediate hosts for the horsehair worm Paragordius varius , which causes its definitive host ,

13068-656: The open prairies where they engaged in communal hunts for buffalo (bison) . In the northern forests, the Ottawas and Potawatomis separated into small family groups for hunting. The Winnebagos and Menominees used both hunting methods interchangeably and built up widespread trade networks extending as far west as the Rockies, north to the Great Lakes, south to the Gulf of Mexico , and east to the Atlantic Ocean. The Hurons reckoned descent through

13200-459: The pharyngeal cavity that help to prevent large pieces of debris from damaging the delicate gills. A smaller opening, the spiracle , lies in the back of the first gill slit . This bears a small pseudobranch that resembles a gill in structure, but only receives blood already oxygenated by the true gills. The spiracle is thought to be homologous to the ear opening in higher vertebrates . Most sharks rely on ram ventilation, forcing water into

13332-572: The plains and rolling hills of the Great Plains of North America. Their colorful equestrian culture and famous conflicts with settlers and the US Army have made the Plains Indians archetypical in literature and art for American Indians everywhere. Plains Indians are usually divided into two broad classifications, with some degree of overlap. The first group were fully nomadic, following the vast herds of buffalo . Some tribes occasionally engaged in agriculture, growing tobacco and corn primarily. These included

13464-550: The practise of gift giving which they now saw as unnecessary. This, in combination with an underwhelming trade relationship with a surplus of whiskey, increase in prices generally, and a shortage of other goods led to unrest among the Indians that was exacerbated by the decision to significantly reduce the amount of rum being traded, a product that British merchants had been including in the trade for years. This would eventually culminate in Pontiac's War , which broke out in 1763. Following

13596-458: The process of bioturbation. By burrowing in the bottom of lakes and redistributing nutrients, mayflies indirectly regulate phytoplankton and epibenthic primary production. Once burrowing to the bottom of the lake, mayfly nymphs begin to billow their respiratory gills. This motion creates current that carries food particles through the burrow and allows the nymph to filter feed. Other mayfly nymphs possess elaborate filter feeding mechanisms like that of

13728-448: The processing of the pelts necessary to the fur trade. Women were integral to the fur trade and their contributions were lauded, so much so that the absence of the involvement of an Indian Woman was once cited as the cause for a trader's failure. When the French fur trade re-opened in 1716 upon the discovery that their overstock of pelts had been ruined, legal French traders continued to marry Indian women and remain in their villages. With

13860-536: The region (as it was in other regions), with Wisconsin a major center. Under the La Follettes , Wisconsin fought against the Republican bosses and for efficiency, modernization, and the use of experts to solve social, economic, and political problems. Gill With the exception of some aquatic insects , the filaments and lamellae (folds) contain blood or coelomic fluid , from which gases are exchanged through

13992-759: The region include, from east to west, the Ohio River , the Upper Mississippi River , and the Missouri River . The 2020 United States census put the population of the Midwest at 68,995,685. The Midwest is divided by the U.S. Census Bureau into two divisions. The East North Central Division includes Illinois, Indiana, Michigan, Ohio, and Wisconsin, all of which are also part of the Great Lakes region . The West North Central Division includes Iowa, Kansas, Minnesota, Missouri, North Dakota, Nebraska, and South Dakota, several of which are located, at least partly, within

14124-508: The region is composed of swing states , and therefore is heavily contested and often decisive in elections. The term West was applied to the region in British America and in the early years of the United States, when the colonial territories had not extended far from the Atlantic coast and the Pacific seaboard was generally unknown. By the early 19th century, anything west of Appalachia

14256-537: The same time as many mayflies emerge. From the Permian , numerous stem group representatives of mayflies are known, which are often lumped into a separate taxon Permoplectoptera (e.g. including Protereisma permianum in the Protereismatidae , and Misthodotidae ). The larvae of Permoplectoptera still had 9 pairs of abdominal gills, and the adults still had long hindwings. Maybe the fossil family Cretereismatidae from

14388-405: The sediment where they spend two or three years before hatching into subimagos. When ready to emerge, several different strategies are used. In some species, the transformation of the nymph occurs underwater and the subimago swims to the surface and launches itself into the air. In other species, the nymph rises to the surface, bursts out of its skin, remains quiescent for a minute or two resting on

14520-507: The septum of the gill arch in front of the first gill. In bony fish , the gills lie in a branchial chamber covered by a bony operculum. The great majority of bony fish species have five pairs of gills, although a few have lost some over the course of evolution. The operculum can be important in adjusting the pressure of water inside of the pharynx to allow proper ventilation of the gills, so bony fish do not have to rely on ram ventilation (and hence near constant motion) to breathe. Valves inside

14652-472: The shortest adult lifespan of any mayfly: the adult females of the species live for less than five minutes. Male adults may patrol individually, but most congregate in swarms a few metres above water with clear open sky above it, and perform a nuptial or courtship dance. Each insect has a characteristic up-and-down pattern of movement; strong wingbeats propel it upwards and forwards with the tail sloping down; when it stops moving its wings, it falls passively with

14784-558: The south. The U.S. Census Bureau's definition consists of 12 states in the north central United States: Illinois , Indiana , Iowa , Kansas , Michigan , Minnesota , Missouri , Nebraska , North Dakota , Ohio , South Dakota , and Wisconsin . The region generally lies on the broad Interior Plain between the states occupying the Appalachian Mountain range and the states occupying the Rocky Mountain range . Major rivers in

14916-426: The spiracles, almost as if the insect were in atmospheric air. Carbon dioxide diffuses into the surrounding water due to its high solubility , while oxygen diffuses into the film as the concentration within the film has been reduced by respiration , and nitrogen also diffuses out as its tension has been increased. Oxygen diffuses into the air film at a higher rate than nitrogen diffuses out. However, water surrounding

15048-474: The subimagos have forelegs that are short and compressed, with accordion like folds, and expands to more than double its length after moulting. After a period, usually lasting one or two days but in some species only a few minutes, the subimago moults to the full adult form, making mayflies the only insects where a winged form undergoes a further moult. Adult mayflies, or imagos , are relatively primitive in structure, exhibiting traits that were probably present in

15180-406: The surface of highly vascularised gills over which a one-way current of water is kept flowing by a specialised pumping mechanism. The density of the water prevents the gills from collapsing and lying on top of each other, which is what happens when a fish is taken out of water." Usually water is moved across the gills in one direction by the current, by the motion of the animal through the water, by

15312-401: The surface to drink a little water before flying off. Females typically lay between four hundred and three thousand eggs. The eggs are often dropped onto the surface of the water; sometimes the female deposits them by dipping the tip of her abdomen into the water during flight, releasing a small batch of eggs each time, or deposits them in bulk while standing next to the water. In a few species,

15444-525: The surfaces of their bodies. Gills of various types and designs, simple or more elaborate, have evolved independently in the past, even among the same class of animals. The segments of polychaete worms bear parapodia many of which carry gills. Sponges lack specialised respiratory structures, and the whole of the animal acts as a gill as water is drawn through its spongy structure. Aquatic arthropods usually have gills which are in most cases modified appendages. In some crustaceans these are exposed directly to

15576-471: The thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks , crustaceans , insects, fish, and amphibians . Semiterrestrial marine animals such as crabs and mudskippers have gill chambers in which they store water, enabling them to use

15708-481: The trade in both the Ohio River valley and the French pays d'en haut with the temporary closing of the French fur trade from 1690 to 1716 and beyond. French fur traders were forced to abandon most posts and those remaining in the region became illegal traders who potentially sought these marriages to secure their safety. Another benefit for French traders marrying Indian women was that the Indian women were in charge of

15840-468: The upper Midwest. The party opposed the expansion of slavery and stressed the Protestant ideals of thrift, a hard work ethic, self-reliance, democratic decision making, and religious tolerance. In the early 1890s, the wheat-growing regions were strongholds of the short-lived Populist movement in the Plains states. Starting in the 1890s, the middle class urban Progressive movement became influential in

15972-402: The walls of the pharynx , along a series of gill slits opening to the exterior. Most species employ a countercurrent exchange system to enhance the diffusion of substances in and out of the gill, with blood and water flowing in opposite directions to each other. The gills are composed of comb-like filaments, the gill lamellae , which help increase their surface area for oxygen exchange. When

16104-555: The water, marine fishes drink large amounts of sea water while simultaneously expending energy to excrete salt through the Na /K -ATPase ionocytes (formerly known as mitochondrion-rich cells and chloride cells ). Conversely, fresh water contains less osmolytes than the fish's internal fluids. Therefore, freshwater fishes must utilize their gill ionocytes to attain ions from their environment to maintain optimal blood osmolarity. Lampreys and hagfish do not have gill slits as such. Instead,

16236-421: The water, while in others, they are protected inside a gill chamber . Horseshoe crabs have book gills which are external flaps, each with many thin leaf-like membranes. Many marine invertebrates such as bivalve molluscs are filter feeders . A current of water is maintained through the gills for gas exchange, and food particles are filtered out at the same time. These may be trapped in mucus and moved to

16368-442: The water. They have an elongated, cylindrical or somewhat flattened body that passes through a number of instars (stages), moulting and increasing in size each time. When ready to emerge from the water, nymphs vary in length, depending on species, from 3 to 30 mm (0.12 to 1.18 in). The head has a tough outer covering of sclerotin , often with various hard ridges and projections; it points either forwards or downwards, with

16500-424: Was a system that would evolve over time. Goods often traded included guns, clothing, blankets, strouds, cloth, tobacco, silver, and alcohol. The French and Indian exchange of goods was called an exchange of gifts rather than a trade. These gifts held greater meaning to the relationship between the two than a simple economic exchange because the trade itself was inseparable from the social relations it fostered and

16632-400: Was bounded by the Great Lakes and the Ohio and Mississippi Rivers. Some entities in the Midwest have "Northwest" in their names for historical reasons, such as Northwestern University in Illinois. One of the earliest late-19th-century uses of Midwest was in reference to Kansas and Nebraska to indicate that they were the civilized areas of the west. Another term applied to the same region

16764-698: Was considered American frontier . Over time the American frontier moved to west of the Mississippi River . During the colonial period, the upper-Mississippi watershed including the valleys of the Missouri River and the Illinois River , which were settled in the 17th and 18th century and called Illinois Country . In 1787 the Northwest Ordinance was enacted, creating the Northwest Territory , which

16896-430: Was formed on the foundations of mutual accommodation and common meanings established between the French and the Indians that then transformed and degraded as both were steadily lost as the French ceded their influence in the region in the aftermath of their defeat in the Seven Years' War and the Louisiana Purchase . Major aspects of the middle ground include blended culture, the fur trade , Native alliances with both

17028-545: Was introduced in 1979 by W. P. McCafferty and George F. Edmunds. The list is based on Peters and Campbell (1991), in Insects of Australia . Suborder Pannota Suborder Schistonota After Siphluriscidae Baetidae Baetiscidae Prosopistomatidae Coloburiscidae Leptophlebiidae Chromarcyidae Oligoneuriidae Vietnamellidae Austremerellidae Teloganodidae Midwestern United States The Midwestern United States (also referred to as

17160-553: Was originally collected from the Ohio River near Cincinnati , but this species has not been seen since its original collection in the 1800s. Ephemera compar is known from a single specimen, collected from the "foothills of Colorado" in 1873, but despite intensive surveys of the Colorado mayflies reported in 1984, it has not been rediscovered. The International Union for Conservation of Nature (IUCN) red list of threatened species includes one mayfly: Tasmanophlebia lacuscoerulei ,

17292-514: Was part of his thinking every day of life. Ottawa and Potawatomi people had very similar religious beliefs to those of the Chippewas. In the Ohio River Valley, the dominant food supply was not hunting but agriculture. There were orchards and fields of crops that were maintained by indigenous women. Corn was their most important crop. The Plains Indians are the indigenous peoples who live on

17424-413: Was the primary crop of Mississippian farmers. They gathered a wide variety of seeds, nuts, and berries, and fished and hunted for fowl to supplement their diets. With such an intensive form of agriculture , this culture supported large populations. The Mississippi period was characterized by a mound-building culture. The Mississippians suffered a tremendous population decline about 1400, coinciding with

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