Cepaea és un gènere de cargols de terra. Tenen una mida mitjana i la seva conquilla presenta sovint colors llampants i bandes fosques i una gran variabilitat cromàtica.
Aquest gènere inclou quatre espècies en dos subgèneres: [2]
Subgènere Cepaea
Subgènere Austrotachea
Cepaea hortenis i Cepaea nemoralis presenten una gran variabilitat cromàtica que ha estat objecte de nombrosos estudis científics. Elprojecte el lideren l'Open University i la University College de Londres. El nom d'aquest projecte és "Evolution Megalab".[3]
Cepaea és un gènere de cargols de terra. Tenen una mida mitjana i la seva conquilla presenta sovint colors llampants i bandes fosques i una gran variabilitat cromàtica.
Die Bänderschnecken (Cepaea) sind eine Gattung der Landlungenschnecken (Stylommatophora) aus der Familie der Schnirkelschnecken (Helicidae).
Die Gattung ist durch kugelige Gehäuse mit meist auffälligen braunen Streifen entlang des Gehäuses gekennzeichnet. Von dieser Bänderung rührt der Name der Gattung her. Allerdings gibt es auch rein gelbe oder rosafarbene Exemplare. Der ausgeprägte Polymorphismus in der Gehäusefärbung wird als Antwort auf die Selektion von Räubern wie der Singdrossel, aber auch als Anpassung an unterschiedliche Temperaturen ihrer Lebensräume interpretiert.
Die Gattung kommt in Europa und verschleppt in Nordamerika vor[1]. Die Tiere leben auf Wiesen, in Wäldern, Parks und Gärten. Ihre Aktivitätsperiode reicht in West- und Mitteleuropa von März bis Oktober. Anschließend gehen sie in eine Kältestarre, die ca. fünf Monate anhält.
Die Gattung der Bänderschnecken war bisher in Europa durch vier Arten vertreten. Nach molekulargenetischen Untersuchungen 2015/16 müssen nun zwei Arten anderen Gattungen zugewiesen werden.[2][3] In der Gattung Cepaea verbleiben nur noch zwei Arten (sowie einige fossile Arten):
Die Gerippte Bänderschnecke wurde in die Gattung Caucasotachea C. Boettger, 1909 transferiert (Caucasotachea vindobonensis) und die Wald-Schnirkelschnecke in die Gattung Macularia Martens, 1850 (Macularia sylvatica).[2][3]
Die Bänderschnecken (Cepaea) sind eine Gattung der Landlungenschnecken (Stylommatophora) aus der Familie der Schnirkelschnecken (Helicidae).
Cepaea is a genus of large air-breathing land snails, terrestrial pulmonate gastropod molluscs in the family Helicidae. The shells are often brightly colored and patterned with brown stripes. The two species in this genus, C. nemoralis and C. hortensis, are widespread and common in Western and Central Europe and have been introduced to North America. Both have been influential model species for ongoing studies of genetics and natural selection. Like many Helicidae, these snails use love darts during mating.[2]
For a long time, four species were classified in the genus Cepaea. However, molecular phylogenetic studies suggested that two of them should be placed in the genera Macularia and Caucasotachea, which are not immediate relatives either of Cepaea or each other:[3][4]
The range of C. hortensis extends further north than that of C. nemoralis in Scotland and Scandinavia and it is the only one of the two species in Iceland.[5][6] Likewise in the Swiss Alps C. hortensis is found as high as 2050 m, but C. nemoralis only up to 1600 m.[7] Conversely, the southern edge of the range lies further north in C. hortensis; unlike C. nemoralis it does not occur in Italy, and in Spain it has a more restricted distribution (in the north-east corner).[8][9]
Where the ranges overlap C. hortensis prefers cooler sites with longer and damper vegetation. But the two species often co-occur at a site, in which situation the densities of both affect each other's growth, fecundity and mortality. However, they differ somewhat in their behaviour: C. hortensis is more active at lower temperatures, aestivates higher on the vegetation and is more diurnal, although this appears to be independent of whether the other species is present or not.[10][11]
When given no choice of partner in the laboratory, the two Cepaea species can form hybrids, which will backcross with the parental species, but the fertility is very low.[12]
The two Cepaea species share a genetic polymorphism for the colour and banding pattern of the shell.
The background colour of the shell ranges from dark brown, through pink to yellow or even approaching white. This variation is continuous, but there are peaks in the distribution corresponding to brown, pink and yellow morphs.[13] The colour is mainly determined by alleles at a single locus with brown dominant to pink, which is dominant to yellow.[11]
Up to five bands (very rarely more) run spirally around the shell, numbered 1 to 5 with the larger numbers further from the shell apex. The conventional scoring annotation is to write 12345 if all bands are present and separated, but to replace a number with 0 if a band is absent from its usual position and to enclose numbers in parentheses if bands are fused with their neighbours. Thus 003(45) would mean that the top two bands are absent and the lower two fused.[14]
A dominant allele at one locus causes the absence of all bands, a dominant allele at another locus causes the loss of all bands except band 3, and a dominant allele at a third locus causes the loss of just bands 1 and 2. The first of these three loci is closely linked to the locus determining shell colour, to another influencing the spread of the band pigment, and to one determining the colour of the lip and bands. This collection of linked loci are part of a supergene. A consequence of this arrangement is that the shells of different background colours within a population often exhibit different ratios of banded to unbanded shells: this is an example of linkage disequilibrium.[11]
The bands are usually dark brown, but this is affected by genes influencing intensity and colouration (e.g. black or orange). Another locus (part of the supergene) determines whether the band is continuous or forms a sequence of spots. The genetics underlying the fusion of adjacent bands is not well understood.[11]
In both species, most populations exhibit polymorphism in one or more of these shell characters. Nevertheless, statistically we can detect systematic variation at continental scales, and also between habitats, and at various scales down to a few tens of metres. There is also statistical evidence of change with time, based both on comparisons between sub-fossil and modern shells,[15] and on resampling the same sites some decades apart, although the latter has more often found little change over the period (stasis).[16] Very much research in ecological genetics has addressed the reasons for both the variation and the systematic trends.[11][17]
The two selection pressures that might most feasibly act on the appearance of shells are climatic selection and predation. Darker shells heat up more quickly in the sun, which might well be advantageous for cold-blooded animals in shaded woodland but risks causing overheating and death in open habitats.[18][19] This trade-off is also presumed to be responsible for the greater proportion of yellow C. nemoralis to the south, but it is curious why the trend is not present in C. hortensis.[11] Contrary to predictions, recent global warming has not led to a detectable increase in yellow morphs on a continental scale.[20] The use of photosensitive paint has shown that paler morphs spend more time exposed to the sun, which may imply that the shell polymorphism allows different morphs to coexist at a site by occupying different microhabitats.[21]
Both temperature regulation and predation make the same prediction of pale shells in open habitats and dark shells in woodland, so—although the prediction has often been confirmed[22]—it is difficult to test which is the more important explanation. However, song thrushes (Turdus philomelos) break open Cepaea shells on stones ("anvils"), allowing a comparison of those they predate with those present in the local environment. Besides the directional selection favouring camouflaged individuals,[23] visually searching predators might cause apostatic selection. The hypothesis is that they form a search image for the commonest morphs, favouring whichever morphs are locally rare, thus promoting diversity.[24] As well as its visual effect, the shell pigments are associated with differences in shell strength, so may affect predation by predators searching non-visually, for instance at night.[25]
Several studies have demonstrated a predicted evolutionary response of shell appearance to a change of habitat.[26] However, the association of shell appearance and habitat is not always consistent, especially in more disturbed environments,[22] so it is believed that random effects are also influential, particularly founder effects. The two Cepaea species colonised much of Europe only within the last 4000 generations,[17] so the time available for selection to act has been limited, and local anthropogenetic disturbances must often have reversed which morphs are optimal. Moreover, snails disperse more slowly than many other animals, so the most suitable genes may be locally absent.
For instance, biologists were at one time puzzled by the phenomenon of "area effects"; the same morph of Cepaea may be found consistently over a wide area but in adjacent areas of similar habitat a different set of morphs predominate instead, with a sharp transition between. The explanation accepted nowadays is that relatively recently a change of habitat allowed the rapid colonisation of vacant areas by descendants of a few founder individuals until the colony had expanded out to areas occupied by other populations; subsequently intraspecific competition slowed the dispersal of genes into the neighbouring, occupied areas.[27][28][29] Nevertheless, occasional transfer of genes between areas of different habitat is proposed to be important in maintaining the local diversity of phenotypes.[17]
Cepaea is a genus of large air-breathing land snails, terrestrial pulmonate gastropod molluscs in the family Helicidae. The shells are often brightly colored and patterned with brown stripes. The two species in this genus, C. nemoralis and C. hortensis, are widespread and common in Western and Central Europe and have been introduced to North America. Both have been influential model species for ongoing studies of genetics and natural selection. Like many Helicidae, these snails use love darts during mating.
Cepaea es un género de gasterópodos pulmonados terrestres de la familia Helicidae. Tienen un tamaño medio y la concha presenta a menudo colores brillantes y bandas oscuras espirales. Presentan una gran variabilidad cromática que ha sido objeto de numerosos estudios genéticos y evolutivos
El género incluye cuatro especies en dos subgénero s:[2]
Subgénero Cepaea
Subgénero Austrotachea
Cepaea hortenis y Cepaea nemoralis presentan una gran variabilidad cromática que ha sido objeto de numerosos estudios genéticos y evolutivos. En este sentido, se ha iniciado un proyecto liderado por la Open University y la University College de Londres que anima a toda la población europea a investigar estos caracoles para recoger el mayor número de datos sobre las transformaciones que han sufrido en las últimas décadas. El nombre de esta investigación es "Evolution Megalab".[3]
Cepaea es un género de gasterópodos pulmonados terrestres de la familia Helicidae. Tienen un tamaño medio y la concha presenta a menudo colores brillantes y bandas oscuras espirales. Presentan una gran variabilidad cromática que ha sido objeto de numerosos estudios genéticos y evolutivos
Vööttigu (Cepaea) on tigude perekond vööttigulaste sugukonnast.
Neist Eestis elavad C. hortensis ja C. nemoralis.
Vööttigu (Cepaea) on tigude perekond vööttigulaste sugukonnast.
Cepaea est un genre de mollusques gastéropodes de la famille des Helicidae et de la sous-famille des Helicinae.
Cepaea est un genre de mollusques gastéropodes de la famille des Helicidae et de la sous-famille des Helicinae.
Cepaea Held, 1838 è un genere di molluschi gasteropodi della famiglia Helicidae.[1]
Il genere comprende le seguenti specie viventi:[1]
Sono note inoltre due specie fossili:[1]
Cepaea Held, 1838 è un genere di molluschi gasteropodi della famiglia Helicidae.
Juostasraigė ar dryžė (lot. Cepaea) – helicidų (Helicidae) šeimos pilvakojų moliuskų gentis. Dvi šios genties rūšys aptinkamos ir Lietuvoje. Kriauklės dažniausiai labai ryškios spalvos ir su tamsiomis juostomis.[1] Dvi plačiai paplitusios šios genties rūšys, C. hortensis ir C. nemoralis, buvo intensyviai naudojamos kaip modelinis organizmas tiriant genetiką ir natūralią atranką.[2] Būdingos Europai, tačiau introdukuotos populiacijos išplitusios ir kituose žemynuose.[3]
Kaip ir kitos didsraigių rūšys turi kopuliacijos organus.[1]
Genčiai priskiriamos keturios rūšys.[3] Naujausi molekuliniai filogenetiniai tyrimai rodo, kad dvi paskutinės rūšys turėtų būti priskirtos kitai genčiai:[4]
Juostasraigė ar dryžė (lot. Cepaea) – helicidų (Helicidae) šeimos pilvakojų moliuskų gentis. Dvi šios genties rūšys aptinkamos ir Lietuvoje. Kriauklės dažniausiai labai ryškios spalvos ir su tamsiomis juostomis. Dvi plačiai paplitusios šios genties rūšys, C. hortensis ir C. nemoralis, buvo intensyviai naudojamos kaip modelinis organizmas tiriant genetiką ir natūralią atranką. Būdingos Europai, tačiau introdukuotos populiacijos išplitusios ir kituose žemynuose.
Kaip ir kitos didsraigių rūšys turi kopuliacijos organus.
Cepaea is een geslacht van middelgrote landslakken uit de familie Helicidae.
De schelpen van de soorten uit dit geslacht zijn vaak felgekleurd en hebben een streepjespatroon.
Tot het geslacht Cepaea behoren de volgende soorten:
Цепе́и[2] (Cepaea) — род моллюсков семейства гелицид.
Крупные наземные улитки. Высота раковины 15—16 мм, диаметр 18—20 мм, длина ползущего животного около 40 мм. Раковина кубаревидно-шаровидная, имеет 4,5—5,5 оборота, пупок полностью закрыт. На белом или желтом фоне раковины до 5 темных лент (иногда они могут отсутствовать). Скульптура раковины в виде тонких радиальных морщин. Устье раковины косое, его края и губа белого цвета в отличие от красновато-коричневого устья родственного вида Cepaea nemoralis L. Голова и нога улитки светло-серые, просвечивающие.
Страны Центральной и Северной Европы, в некоторых из них (Финляндия) вид нередок. В пределах России известен из Калининградской и Ленинградской областей. В Санкт-Петербурге обитает на Ижорской возвышенности.
Цепеи обитают на хорошо прогреваемых участках травяно-дубравных широколиственных лесов на карбонатных почвах, сложившихся на ордовикских отложениях. Молодь питается детритом, грибами и лишайниками и придерживается нижних ярусов леса, поверхности почвы, подстилки. Взрослые улитки часто поднимаются по стволам деревьев, кустарников, по стеблям травянистых растений, которыми дополняют рацион. Яйца откладывают в почву, под валежник, в моховые подушки.
Вырубка широколиственных пород деревьев; сбор живых моллюсков коллекционерами и хозяйственная деятельность человека, связанная с разрушением биотопов в местах обитания вида.
Охрана широколиственных лесов на карбонатных почвах. Внесение вида в списки особо охраняемых объектов памятника природы «Дудергофские высоты». Запрет сбора живых улиток в целях коллекционирования.
Это заготовка статьи по малакологии. Вы можете помочь проекту, дополнив её. Цепе́и (Cepaea) — род моллюсков семейства гелицид.
