Topic
Orconectes
About: Orconectes is a research topic. Over the lifetime, 414 publications have been published within this topic receiving 12871 citations.
Papers published on a yearly basis
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Papers
TL;DR: A conceptual model is presented as a possible way forward for protecting the future survival of ICS in Europe from habitat loss, deteriorating water quality, overfishing, climate change, and most importantly from NICS and crayfish plague.
Abstract: Non-indigenous crayfish species (NICS) in Europe now outnumber indigenous crayfish species (ICS) 2:1, and it has been predicted that they may dominate completely in the next few decades unless something is done to protect them. Of the ten NICS introduced at least nine have become established in areas occupied by four of the five ICS. A decline in stocks of ICS has been recorded in many countries in the face of increasing populations of NICS. Most European countries retain at least one ICS but all are under threat from habitat loss, deteriorating water quality, overfishing, climate change, and most importantly from NICS and crayfish plague. The threat to ICS is so great in some countries that “ark”sanctuary sites are being established.The three most widely-spread NICS are the North American species: Pacifastacus leniusculus , Orconectes limosus and Procambarus clarkii . These can be considered as “Old NICS”, which were introduced before 1975, compared with the “New NICS”, which were introduced after 1980, such as the North American species: Orconectes immunis , Orconectes juvenilis , Orconectes virilis , Procambarus sp. and Procambarus acutus ; and the Australian species: Cherax destructor and Cherax quadricarinatus , all of which have much narrower ranges in Europe. The North American species are potentially capable of acting as vectors of crayfish plague. Outbreaks of this disease occur regularly where there are high concentrations of vectors.In addition to the NICS currently established in the wild, a further threat exists through the aquarium trade, where many American and Australian species are available via the internet and in aquarist centres. Owners of such species may discard them into the freshwater environment when they grow too big as with some Cherax spp. and Orconectes spp., or multiply too frequently as with Procambarus sp. (a parthenogenetic species). A conceptual model is presented as a possible way forward for protecting the future survival of ICS in Europe.
529 citations
TL;DR: A technique developed to estimate intraspecific cladograms com- bined with more traditional methods of phylogenetic estimation can improve the estimate in data sets containing a range of diversity when the lower bound of the range approaches 0% divergence.
Abstract: The use of comparative methods to test evolutionary hypotheses has become more common at both the macro- and microevolutionary levels. The application of such techniques is especially troublesome at the interface of these levels because phylogenetic relationships are often difficult to estimate. The use of a technique developed to estimate intraspecific cladograms com- bined with more traditional methods of phylogenetic estimation can improve the estimate in data sets containing a range of diversity when the lower bound of the range approaches 0% divergence. For nucleotide sequence data from the 16S region of the mitochondrial DNA from 72 individuals representing 37 species, this combined-procedures approach improved the estimate of phyloge- netic relationships using maximum-parsimony, maximum-likelihood, and neighbor-joining meth- ods. The estimated trees were used to examine systematic hypotheses relating to the crayfish genus Orconectes and species relationships within the subgenus Procericambarus. The monophyly of Procericambarus is not supported by the mitochondrial data, and the hypotheses of unique origins of various morphological features previously used in determining crayfish relationships is unsupported. (Crayfish; mitochondrial DNA; molecular systematics; parsimony; phylogeny re- construction; Orconectes.)
439 citations
TL;DR: Using long-term field data and laboratory experiments, mechanisms of differential impact of O. rusticus (relative to congeners) on benthic community structure are explored and feeding preference did not differ among morphologically different macrophytes or between different-sized snails; however, weight-specific consumption and destruction rates did.
Abstract: Since its introduction 30 yr ago, Orconectes rusticus has displaced O. propinquus and O. virilis and reduced macrophytes in several northern Wisconsin lakes. Since 1973, rate of displacement by O. ...
229 citations
TL;DR: In this article, the importance of vision for efficient agonistic communication was investigated in the rusty crayfish, Orconectes rusticus, a species active both day and night, using infra-red video recording.
Abstract: 1. The importance of vision for efficient agonistic communication was investigated in the rusty crayfish, Orconectes rusticus, a species active both day and night. Agonistic bout dynamics were analyzed from isosexual pairs of males and females interacting under moderate (350 lux) and dim (11 lux) light levels, and in complete darkness (using infra-red video recording). Under dim light we determined the effect of visual light and dark adaptation on communication. 2. As light diminished, bouts became less frequent, but longer, and the crayfish invested more time and performed more acts when resolving bouts. Thus, communication efficiency was clearly lower in the dark than under moderate light, for both sexes. Males performed more acts than females overall, and were generally more aggressive than females. 3. The frequency of visually-mediated behaviours (e.g. Lunge, Follow) decreased in the absence oflight, while tactile behaviours (e.g. Antenna Tap, Chela Strike, Push) were performed more frequently. Males especially performed more highly aggressive tactile behaviours in the dark. It was shown that some behaviours previously considered to be visually mediated (e.g. Meral Spread) are also tactually or proprioceptively mediated, and some behaviours assumed to be tactually mediated (e.g. antennal movements) are probably also visually mediated. 4. Under dim light, crayfish with light-adapted eyes resolve bouts more efficiently in terms of time and energy investment than do dark-adapted animals. This is consistent with the effects of pigment migrations during dark adaptation in the crayfish superposition compound eye, which enhance visual sensitivity, but decrease acuity. We suggest that dark adaptation diminishes a crayfishes ability to deal with the subtleties of visual communication, but may well enhance its ability to detect predators.
221 citations
TL;DR: Field and experimental data suggest that the stream species, O. virilis, is excluded from ponds by summer drying and periodic low oxygen periods of those ponds, and is not as competent a burrower as O. immunis nor is its as tolerant of low oxygen levels.
Abstract: The two crayfish, Orconectes virlis and O. immunis, have similar ranges but are ecologically isolated within these ranges; the former species inhabits streams and lake margins, the latter inhabits ponds and sloughs. Field and experimental data suggest that the stream species, O. virilis, is excluded from ponds by summer drying and periodic low oxygen periods of those ponds. It is not as competent a burrower as O. immunis nor is its as tolerant of low oxygen levels. Neither current nor substratum excludes the pond species, O. immunis, from the stream. But both field and laboratory observations strongly indicate a competitive exclusion of O. immunis by O. virilis. The latter was demonstrated to be intrinsically more aggressive in interspecific contacts, and in other experiments, evicted O. immunis from crevices in the substratum.
204 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 3 |
| 2019 | 3 |
| 2018 | 10 |
| 2017 | 11 |
| 2016 | 21 |
| 2015 | 14 |