Mutualisms

2001 ◽  
Author(s):  
Judith L. Bronstein
Keyword(s):  
20Th Century ◽  
Evolutionary Ecology ◽  
Popular Literature ◽  
Freshwater Species ◽  
Unusual Behavior ◽  
Cleaner Fish ◽  
Scientific Curiosity ◽  
Fitness Benefits ◽  
Host Fishes ◽  
The Tropics

The unusual behavior of cleaner fish has attracted both popular and scientific curiosity since its discovery early in the 20th century. These fish apparently make their living by removing external parasites from “host” fishes of other species (some also remove bacteria or diseased and injured tissue). When they approach cleaners, hosts assume an unusual motionless posture that allows cleaners to feed from their scales, from their gill cavities, or even inside their mouths. For their trouble, cleaner fish get a meal, and hosts get a good cleaning. The interaction between cleaner fish and their hosts is generally classified as a mutualism, or mutually beneficial interaction between species. Stories about this and other mutualisms have become staples of nature documentaries and the popular literature and have helped lure many students into a lifetime of studying biology. From the perspective of evolutionary ecology, however, the cleaner-host relationship is anything but straightforward (Poulin and Grutter 1996). First, it is not at all clear that this interaction confers reciprocal fitness benefits. Despite several decades of effort, only one study has shown that cleaners significantly reduce hosts’ parasite loads (Grutter 1999), and none has yet demonstrated that reducing parasite loads increases host success. Since cleaners often gouge the host’s flesh, particularly when parasites are few, the interaction is often more costly than beneficial. Second, if cleaning does not confer an advantage, it is not evident why hosts should tolerate and even actively solicit cleaners’ attention. In fact, sometimes hosts lure cleaners only to eat them, but the conditions under which it might be beneficial for a host to doublecross its cleaners like this remain unexplored. Third, we don’t really understand how cleaning behaviors arose in the first place, considering that the first individuals that approached hosts to feed on parasites were very likely eaten. Despite this constraint, cleaning has apparently evolved multiple times; it is found in at least five families, in both marine and freshwater species, and in both the temperate zone and the tropics.

scholarly journals Relative Importance of Cleaning Behaviour in Centrolabrus Exoletus and other Wrasse at Arrábida, Portugal

1997 ◽  
Vol 77 (3) ◽  
pp. 891-898 ◽  
Author(s):  
Miguel Henriques ◽  
Vitor C. Almada
Keyword(s):  
Reef Fishes ◽  
Relative Importance ◽  
Cleaner Fish ◽  
Cleaning Behaviour ◽  
North Eastern ◽  
In Captivity ◽  
Tropical Reef ◽  
Ctenolabrus Rupestris ◽  
Labrus Bergylta ◽  
Host Fishes

Underwater behavioural observations were conducted to evaluate the relative importance of cleaning behaviour in three species of common north-eastern Atlantic wrasse (Teleostei: Labridae). At the study site, the only cleaner was Centrolabrus exoletus. A total of 12 species was cleaned, with the wrasse, Symphodus melops and Labrus bergylta being the species most frequently cleaned. Neither S. melops nor Ctenolabrus rupestris, known to be cleaners in other sites or in captivity, could be observed cleaning other fishes. Centrolabrus exoletus was found to be a facultative cleaner fish with cleaning acts representing only 7% of the observed feeding acts. In focal observations of host fishes, the incidence of cleaning acts reached a level (11 h-1 per host) similar to that reported for tropical reef fishes and probably reflects the high numbers of cleaners available. Some factors that may affect the origin of the cleaning interactions are discussed.

Natural Selection

2001 ◽  
Author(s):  
Daphne J. Fairbairn ◽  
Jeff P. Reeve
Keyword(s):  
Natural Selection ◽  
20Th Century ◽  
Evolutionary Ecology ◽  
Natural Populations ◽  
Modern Biology ◽  
Functional Connection ◽  
Late 20Th Century ◽  
Chance Events ◽  
Subdivided Populations ◽  
Natural Philosophers

The theory that organisms become adapted to their environment through the process of natural selection has become so ingrained in modern biological thought, and more generally in Western culture of the late 20th century, that it is surely one of the great scientific paradigms of the present era. Evolution and adaptation were both well-accepted concepts by the mid-19th century, at least among French and British natural philosophers. The theory of natural selection, developed by Wallace (1858) and Darwin (1859), provided a functional connection between the two processes. However, despite its logical consistency, natural selection was not accepted as a necessary or sufficient explanation for adaptation until the “evolutionary synthesis” of the mid-20th century, when knowledge from population and quantitative genetics, natural history (e.g., biogeography, ecology, behavior), systematics, and paleontology merged to form the unified theory of adaptive evolution known as neo-Darwinism (see Futuyma 1998 for a concise review of this history). Since that time, natural selection has been accepted as the universal mechanism leading to adaptation, and the two terms have become so closely associated as to be almost tautological. Adaptationist hypotheses are now fundamental to much of modern biology and are becoming increasingly apparent in more disparate fields, such as anthropology, medicine, biochemistry, and psychology (Futuyma 1999). Nevertheless, there is much that natural selection cannot explain. For example, chance events may strongly influence macroevolutionary trends (i.e., the origin and extinction of species and higher taxa), some aspects of molecular evolution, and evolution within small or subdivided populations (Mazer and Damuth, this volume, chapter 2; Nunny, this volume). For this reason, adaptationist hypotheses should be viewed with skepticism until adequately tested (Reznick and Travis, this volume). In this chapter, we carefully define natural selection and discuss methods of measuring selection in natural populations as a means of testing adaptationist hypotheses. These methods are most appropriate for testing hypotheses concerning the adaptive significance of contemporary trait distributions within and among populations (“microevolutionary” hypotheses) and thus have particular relevance for evolutionary ecologists. Readers will find many additional examples of these and other methods of testing microevolutionary adaptationist hypotheses throughout this volume, such tests being an essential component of most research programs in evolutionary ecology.

Temporal trends in non-indigenous freshwater species records during the 20th century: a case study in the Iberian Peninsula

2010 ◽  
Vol 19 (12) ◽  
pp. 3471-3487 ◽  
Author(s):  
Fernando Cobo ◽  
Rufino Vieira-Lanero ◽  
Enrique Rego ◽  
María J. Servia
Keyword(s):  
Iberian Peninsula ◽  
20Th Century ◽  
Temporal Trends ◽  
Freshwater Species

A new freshwater species of Herpotrichia from the tropics

Nova Hedwigia ◽  
1998 ◽  
Vol 66 (1-2) ◽  
pp. 247-249 ◽  
Author(s):  
Kevin D. Hyde ◽  
André Aptroot
Keyword(s):  
Freshwater Species ◽  
The Tropics

G. W. M. Reynolds

2011 ◽  
Author(s):  
Anne Humpherys
Keyword(s):  
United States ◽  
Middle Class ◽  
20Th Century ◽  
19Th Century ◽  
21St Century ◽  
Popular Literature ◽  
The United States ◽  
Early 20Th Century ◽  
Periodical Press ◽  
The 19Th Century

George William Macarthur Reynolds (b. 1814–d. 1879) was at his death labeled “the most popular writer of our time” by the Bookseller in its short obituary. This popularity rested on two achievements: first, the mammoth twelve-volume series of “mysteries” novels, The Mysteries of London (1846–1848) and The Mysteries of the Court of London (1848–1855), and, second, his involvement with Chartist politics, which led in 1850 to his founding and editing the radical Sunday newspaper Reynolds’s Newspaper, which lasted in some form until 1962. The Mysteries novels were also constantly in print in a variety of cheap formats for most of the 19th century. Reynolds was a controversial figure both among working-class radicals, who doubted his commitment, and among the middle-class literary establishment, which abhorred his popular sensationalist novels. Dickens was probably referring to him as the “draggled fringe on the Red Cap, Pander to the basest passions of the lowest natures—whose existence is a national reproach” in the opening number of Household Words in 1850. Sometime shortly after 1860, Reynolds essentially stopped writing and editing. But the influence of his mysteries series continued, especially in the United States, India, and other countries. His novels fell out of print in the early 20th century; he himself became relatively unknown among historians and literary critics. This neglect lasted until the second half of the 20th century, at which point a number of scholars began to analyze Reynolds’s importance in 19th-century popular literature, politics, and the periodical press, a development that gathered force in the first decade of the 21st century. There is now a G.W.M. Reynolds Society, available online.

scholarly journals The Mechanization of Motherhood: Images of Maternity in Quebec Women Writers of the Quiet Revolution

AmeriQuests ◽  
2007 ◽  
Vol 4 (1) ◽  
Author(s):  
Susan K Kevra
Keyword(s):  
Women Writers ◽  
20Th Century ◽  
Short Story ◽  
Rural Women ◽  
Health Care Professionals ◽  
Popular Literature ◽  
Historical Evidence ◽  
Quiet Revolution ◽  
Social Agenda ◽  
Civic Group

In her short story “Le Peuplement de la Terre” (“Be Fruitful and Multiply”) Madeleine Ferron reveals the reality of married life for generations of women in Quebec whose lives were a constant cycle of pregnancy, childbirth and mothering. Like other Quebec women writers, such as Marie Claire Blais and Gabrielle Roy, Ferron turns on its head the myth of the tireless, dutiful and fulfilled mother, happy to serve God and country by producing offspring. All three of these writers depict motherhood in the period prior to the Quiet Revolution with disturbing images of childbearing automats, leaving us not with a glorified and tender view of motherhood, but rather a mechanization of mothering. Could the preponderance of such imagery in the works of women writers of this period point to attitudes in the medical establishment and in the social agenda of the first half of the 20th century? Using Ferron’s short story as the primary literary example – with parenthetical references to both Une Saison and Bonheur d’Occasion – I provide historical evidence for the increasingly mechanized nature of mothering in Quebec brought on by the ramping up of social, political, religious and economic pressures placed on women in the first part of the 20th century. The historical evidence will take the form of popular literature of health care professionals in Canada and Quebec during this period, as well as the role of the Cercle de Fermières, a kind of civic group for rural women of Quebec whose ideology of super-productive women is summed up in their motto, “Travaillons sans cesse!”

Gendered Expressions of Labor in the Middle East

2016 ◽  
Vol 48 (3) ◽  
pp. 570-573
Author(s):  
Malek Abisaab
Keyword(s):  
Middle East ◽  
Oral History ◽  
20Th Century ◽  
Family Relations ◽  
Popular Literature ◽  
Work Patterns ◽  
Labor Activists ◽  
History Of

A dearth of information is available on workingwomen in the Middle East during the 19th and first half of the 20th century. This gap is compounded by the male biases of the official reporters, journalists, unionists, labor activists, and scholars who produced the information that does exist. Nevertheless, it is possible to write a gendered history of labor on the basis of less-than-ideal sources, which can be enriched by the use of oral history, popular literature, autobiographies, and even fieldwork focused on women's and men's family relations and work patterns.

scholarly journals Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide

2020 ◽  
Vol 117 (7) ◽  
pp. 3648-3655 ◽  
Author(s):  
Valerio Barbarossa ◽  
Rafael J. P. Schmitt ◽  
Mark A. J. Huijbregts ◽  
Christiane Zarfl ◽  
Henry King ◽  
...  
Keyword(s):  
Fish Species ◽  
Multiple Scales ◽  
Water Security ◽  
The United States ◽  
Freshwater Species ◽  
Large Dams ◽  
Hydropower Planning ◽  
Identification Of Species ◽  
The Tropics ◽  
Degree Of Fragmentation

Dams contribute to water security, energy supply, and flood protection but also fragment habitats of freshwater species. Yet, a global species-level assessment of dam-induced fragmentation is lacking. Here, we assessed the degree of fragmentation of the occurrence ranges of ∼10,000 lotic fish species worldwide due to ∼40,000 existing large dams and ∼3,700 additional future large hydropower dams. Per river basin, we quantified a connectivity index (CI) for each fish species by combining its occurrence range with a high-resolution hydrography and the locations of the dams. Ranges of nondiadromous fish species were more fragmented (less connected) (CI = 73 ± 28%; mean ± SD) than ranges of diadromous species (CI = 86 ± 19%). Current levels of fragmentation were highest in the United States, Europe, South Africa, India, and China. Increases in fragmentation due to future dams were especially high in the tropics, with declines in CI of ∼20 to 40 percentage points on average across the species in the Amazon, Niger, Congo, Salween, and Mekong basins. Our assessment can guide river management at multiple scales and in various domains, including strategic hydropower planning, identification of species and basins at risk, and prioritization of restoration measures, such as dam removal and construction of fish bypasses.

scholarly journals To history of ichthiofaunistic research of Karkinitsky Gulf of the Black sea

2020 ◽  
Vol 2020 (2) ◽  
pp. 26-35
Author(s):  
Raisa Belogurova
Keyword(s):  
20Th Century ◽  
Black Sea ◽  
Anthropogenic Factors ◽  
The Black Sea ◽  
Freshwater Species ◽  
The Status ◽  
Fish Juveniles ◽  
History Of ◽  
Feeding Area ◽  
Xix Century

The article is focused on the history of studing the fishfauna of Karkinitsky Gulf of the Black Sea in the XX–XXI centuries. There have been singled out three stages in studying fishfauna of the region: since the late 50’s of the XIX century up to the early 20th century. (K. F. Kessler); at the turn of the 20th century (expeditions of S. A. Zernov, later – researches of L. V. Arnoldi, V. A. Vodyanitsky, K. A. Vinogradov, etc.) up to the 60s of the 20th century; since 2008 to the present day (A. R. Boltachev, E. P. Karpova). Data on the fishfauna of Karkinitsky Gulf during a half-century period has been found insufficient: since late 50s of the 20th century up to the beginning of the 21st century. There has been shown the importance of Karkinitsky Gulf as a habitat for the rare protected fish species and the feeding area of valuable fish juveniles. The influence of anthropogenic factors over the past 50 years has been proved to cause qualitative changes in the composition of the fishfauna of Karkinitsky Gulf: degradation of the seagrass biocenosis in shallow bays caused by siltation due to the discharge of fresh water from the fields and rice paddies, and the replacement of native ichthyofauna by freshwater species. The importance of systematic studies in this area is emphasized to assess the status of the fishfauna of Karkinitsky Gulf

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