Insects in the family Tettigoniidae are commonly called katydids or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, the Tettigoniidae are the only extant (living) family in the superfamily Tettigonioidea.
In parapatric speciation, two subpopulations of a species evolve reproductive isolation from one another while continuing to exchange genes. This mode of speciation has three distinguishing characteristics: 1) mating occurs non-randomly, 2) gene flow occurs unequally, and 3) populations exist in either continuous or discontinuous geographic ranges. This distribution pattern may be the result of unequal dispersal, incomplete geographical barriers, or divergent expressions of behavior, among other things. Parapatric speciation predicts that hybrid zones will often exist at the junction between the two populations.
Roesel's bush-cricket, Roeseliana roeselii is a European bush-cricket, named after August Johann Rösel von Rosenhof, a German entomologist.
Chorthippus jutlandica, the Jutland bow-winged grasshopper, is a species of grasshopper in the subfamily Gomphocerinae. It is endemic to sparsely vegetated coastal sand dunes in an area covering only 87 km2 (34 sq mi) between Blåvandshuk and Hvide Sande in western Jutland, Denmark, but it is common and not considered to be under any threat.
A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form in situ due to the evolution of a new lineage but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their differentiation. Hybrid zones are useful in studying the genetics of speciation as they can provide natural examples of differentiation and (sometimes) gene flow between populations that are at some point between representing a single species and representing multiple species in reproductive isolation.
Chorthippus brunneus, also known as the common field grasshopper, is a species of grasshopper of the subfamily Gomphocerinae. The species is common and widespread in the Western Palearctic, and the IUCN lists it as Least Concern.
Saga pedo is a species of wingless bush cricket from the southern half of Europe and western and central Asia. This brown or green bush cricket typically has a total length, from the head to the tip of the ovipositor, of up to 10.5 cm (4.1 in), but exceptionally it may reach 12 cm (4.7 in), which makes it one of the largest European insects and one of the world's largest Orthoptera. The head-and-body alone typically is 5–7 cm (2.0–2.8 in) long in adults, but may reach up to 7.8 cm (3.1 in).
Chorthippus albomarginatus, the lesser marsh grasshopper, is a common grasshopper of European grassland both damp-marshy and dry, including salt-marsh and coastal habitats.
Phaulacridium marginale is a small species of short-horned grasshopper in the family Acrididae. It is endemic to New Zealand where it is found in low elevation open habitat throughout North Island, South Island, Stewart Island and on many smaller islands.
Aularches miliaris is a grasshopper species of the monotypic genus Aularches, belonging to the family Pyrgomorphidae. A native of South and Southeast Asia, the bright warning colours of this fairly large grasshopper keep away predators and their defense when disturbed includes the ejection of a toxic foam.
Ecological speciation is a form of speciation arising from reproductive isolation that occurs due to an ecological factor that reduces or eliminates gene flow between two populations of a species. Ecological factors can include changes in the environmental conditions in which a species experiences, such as behavioral changes involving predation, predator avoidance, pollinator attraction, and foraging; as well as changes in mate choice due to sexual selection or communication systems. Ecologically-driven reproductive isolation under divergent natural selection leads to the formation of new species. This has been documented in many cases in nature and has been a major focus of research on speciation for the past few decades.
Reinforcement is a process of speciation where natural selection increases the reproductive isolation between two populations of species. This occurs as a result of selection acting against the production of hybrid individuals of low fitness. The idea was originally developed by Alfred Russel Wallace and is sometimes referred to as the Wallace effect. The modern concept of reinforcement originates from Theodosius Dobzhansky. He envisioned a species separated allopatrically, where during secondary contact the two populations mate, producing hybrids with lower fitness. Natural selection results from the hybrid's inability to produce viable offspring; thus members of one species who do not mate with members of the other have greater reproductive success. This favors the evolution of greater prezygotic isolation. Reinforcement is one of the few cases in which selection can favor an increase in prezygotic isolation, influencing the process of speciation directly. This aspect has been particularly appealing among evolutionary biologists.
Reinforcement is a process within speciation where natural selection increases the reproductive isolation between two populations of species by reducing the production of hybrids. Evidence for speciation by reinforcement has been gathered since the 1990s, and along with data from comparative studies and laboratory experiments, has overcome many of the objections to the theory. Differences in behavior or biology that inhibit formation of hybrid zygotes are termed prezygotic isolation. Reinforcement can be shown to be occurring by measuring the strength of prezygotic isolation in a sympatric population in comparison to an allopatric population of the same species. Comparative studies of this allow for determining large-scale patterns in nature across various taxa. Mating patterns in hybrid zones can also be used to detect reinforcement. Reproductive character displacement is seen as a result of reinforcement, so many of the cases in nature express this pattern in sympatry. Reinforcement's prevalence is unknown, but the patterns of reproductive character displacement are found across numerous taxa, and is considered to be a common occurrence in nature. Studies of reinforcement in nature often prove difficult, as alternative explanations for the detected patterns can be asserted. Nevertheless, empirical evidence exists for reinforcement occurring across various taxa and its role in precipitating speciation is conclusive.
Chortophaga viridifasciata, the green-striped grasshopper, is a species of band-winged grasshopper in the family Acrididae.
Pseudochorthippus curtipennis, known generally as marsh meadow grasshopper, is a species of slant-faced grasshopper in the family Acrididae. Other common names include the meadow grasshopper and short-winged brown grasshopper. It is found in North America.
Pseudochorthippus is a genus of grasshoppers in the tribe Gomphocerini. Insects including the 'meadow grasshopper' were previously placed in the genus Chorthippus, but are now placed here in species group parallelus(Zetterstedt, 1821). Species have been recorded from Western Europe, throughout temperate Asia and North America.
Wētā is the common name for a group of about 100 insect species in the families Anostostomatidae and Rhaphidophoridae endemic to New Zealand. They are giant flightless crickets, and some are among the heaviest insects in the world. Generally nocturnal, most small species are carnivores and scavengers while the larger species are herbivorous. Although some endemic birds likely prey on them, wētā are disproportionately preyed upon by introduced mammals, and some species are now critically endangered.
Roger Kenneth Butlin is a British evolutionary biologist and professor at the University of Sheffield. He is known for his work on speciation. He served as Editor of Heredity from 2009 to 2012, and President of the Society for the Study of Evolution from 2013 to 2015. In 2015 he received the Darwin Wallace Medal.
Cyrtacanthacris aeruginosa or simply, green tree locust, is a large species of grasshopper that can be found in the grasslands of Africa. They pertain to the genus Cyrtacanthacris and are composed by three subspecies, C. a. aeruginosa, C. a. flavescens and C. a. goldingi, all three of them are monophyletic. The specie is univoltine, that is, it only produces one brood of offspring per year, furthermore it also experiences egg diapause, meaning that the eggs have a phase of suspended or arrested growth. In terms of overwintering strategy, Aeruginosa adults mate and then the female lay the eggs and die before the dry season, the eggs stay in diapause for 7 months and take 45–67 days to incubate.
Mating
Nymph
Immature
Male, green with brown wings
Female green form
Female showing slight pink coloration
