Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies but are usually smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. Damselflies have existed since the Late Jurassic, and are found on every continent except Antarctica.
Mayflies 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.
Sarcoptes scabiei or the itch mite is a parasitic mite found in all parts of the world that burrows into skin and causes scabies. Humans become infested by Sarcoptes scabiei var. hominis; other mammals can be infested with different varieties of the mite. They include wild and domesticated dogs and cats, ungulates, wild boars, bovids, wombats, koalas, and great apes.
In biology, the imago is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the imaginal stage, the stage in which the insect attains maturity. It follows the final ecdysis of the immature instars.
Hemimetabolism or hemimetaboly, also called partial metamorphosis and paurometabolism, is the mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage, or imago. These groups go through gradual changes; there is no pupal stage. The nymph often has a thin exoskeleton and resembles the adult stage but lacks wings and functional reproductive organs. The hemimetabolous insects differ from ametabolous taxa in that the one and only adult instar undergoes no further moulting.
The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embryology, bioinformatics and scientific computing. It is estimated that the class of insects originated on Earth about 480 million years ago, in the Ordovician, at about the same time terrestrial plants appeared. Insects are thought to have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. The oldest insect fossil has been proposed to be Rhyniognatha hirsti, estimated to be 400 million years old, but the insect identity of the fossil has been contested. Global climate conditions changed several times during the history of Earth, and along with it the diversity of insects. The Pterygotes underwent a major radiation in the Carboniferous while the Endopterygota underwent another major radiation in the Permian.
Erythemis simplicicollis, the eastern pondhawk, also known as the common pondhawk, is a dragonfly of the family Libellulidae, native to the eastern two-thirds of the United States and southern Ontario and Quebec, Canada. It is a dragonfly of ponds and still waters. The species is distinguished in that the female is bright green with a banded abdomen and the mature male has a blue abdomen with a green face and green and blue thorax.
Heteropteryx is a monotypic genus of stick insects containing Heteropteryx dilatata as the only described species. and gives its name to the family of the Heteropterygidae. Their only species may be known as jungle nymph, Malaysian stick insect, Malaysian wood nymph, Malayan jungle nymph, or Malayan wood nymph and because of their size it is commonly kept in zoological institutions and private terrariums of insect lovers. It originates from the Malay Archipelago and is nocturnal.
Ephemerellidae are known as the spiny crawler mayflies. They are a family of the order Ephemeroptera. There are eight genera consisting of a total 90 species. They are distributed throughout North America as well as the UK. Their habitat is lotic-erosional, they are found in all sizes of flowing streams on different types of substrates where there is reduced flow. They are even found on the shores of lakes and beaches where there is wave action present. They move by swimming and clinging, they are very well camouflaged. Most species have one generation per year. They are mostly collector-gatherers.
Ephemera danica, the green drake or green drake mayfly, is a species of mayfly in the genus Ephemera.
Chloroperlidae are a family of stoneflies, commonly known as green stoneflies, with more than 200 species and 22 genera. They appear green to yellow in colour, and are popularly used among fisherman as bait for trout fishing. Green stoneflies live in the benthic zone of the cold streams and rivers of five continents and four zoogeographical regions, emerging from the water to live in the riparian zone as adults. They are sensitive to pollutants, making them an indicator species for determining the quality of water bodies. Chloroperlidae are hemimetabolous, having no pupal stage, but instead hatch from eggs as nymphs and mature directly into adults. They are omnivorous, feeding on small organisms and plant particles, and become more carnivorous as they mature. The classification of Chloroperlidae is contested, with some believing that they should be considered as members of different orders, as opposed to the order Plecoptera that they currently belong to.
Rhithrogena germanica is a European species of mayfly, and is "probably the most famous of all British mayflies", because of its use in fly fishing. It is known in the British Isles as the March brown mayfly, a name which is used in the United States for a different species, Rhithrogena morrisoni. It emerges as a subimago at the end of winter, and can be distinguished from similar species by a dark spot on the femur of each leg.
Behningiidae is a family of mayflies. It is a primitive family; the nymphs burrow in the sediment but lack tusks on their mandibles, and the forelegs are not modified for burrowing. The gills are ventral, and the ones on the first abdominal segment are single and are longer than the gills on the other segments. The forelegs are palp-like and the other two pairs of legs are modified to protect the gills. The family is holarctic in distribution. The genus Dolania occurs in North America and the other three genera occur in northern Europe and Asia.
Ephemera vulgata is a species of mayfly in the genus Ephemera. This mayfly breeds in stationary water in slow rivers and in ponds, the nymphs developing in the mud.
Hexagenia limbata, the giant mayfly, is a species of mayfly in the family Ephemeridae. It is native to North America where it is distributed widely near lakes and slow-moving rivers. The larvae, known as nymphs, are aquatic and burrow in mud and the adult insects have brief lives. They are often referred to as fish flies around the Great Lakes as they tend to cause the areas around water to smell like rotten fish.
Hexagenia bilineata is a species of mayfly in the family Ephemeridae. It is native to North America where it is found in the Upper Mississippi Valley. Sometimes adults of this mayfly are so abundant as to cause a nuisance because of their enormous numbers. The larvae are aquatic and burrow in mud and the adult insects have brief lives.
Leptophlebia marginata, the sepia dun, is a species of mayfly in the family Leptophlebiidae. It is native to Europe and North America where it is distributed widely near lakes, ponds and slow-moving streams. The larvae, which are known as nymphs, are aquatic.
Siphlonisca aerodromia, commonly known as the Tomah mayfly, is an extremely rare species and has only been documented less than 100 times. It was once thought to only known to occur in New York and Northern Maine, but has been since found more recently in eastern Canada as well. The Tomah mayfly is an endangered species and is listed as threatened in both New York and Maine. Its abundance is unknown. The Tomah mayfly is the only species within the monotypic genus Siphlonisca. The Tomah mayfly is a habitat specialist and an indicator species. Adults only live for a few days as they deposit eggs into rivers and streams. Nymphs hatch from eggs and migrate to the floodplains during springtime and following snow melt. They spend most of their lives in the floodplains, feeding on other aquatic invertebrates in order to grow rapidly. The Tomah mayfly was considered as a flagship species and led to the decision not to dam a stream and flood a sedge meadow and therefore conserve the ecosystem.
William L. Peters (1939–2000) was an American entomologist specializing in mayflies, especially those in the family Leptophlebiidae.
