| infections of gyrodactylus bullatarudis and gyrodactylus turnbulli on guppies (poecilia reticulata) in trinidad. | gyrodactylus bullatarudis turnbull, 1956, and gyrodactylus turnbulli harris, 1986, are recorded from guppies (poecilia reticulata) from the northern mountains of trinidad. mixed infections of the 2 species were found at 9 localities. gyrodactylus turnbulli had a predominantly posterior distribution on the fishes, whereas g. bullatarudis was more anteriorly distributed. this is the first record of these species from guppies collected from within their original range. | 1992 | 1403438 |
| temporal changes in aggregation: a laboratory study. | changes in the variance to mean ratio and the parameter k of the negative binomial distribution were used to study temporal changes in the degree of aggregation of the monogenean parasite, gyrodactylus turnbulli in free-running laboratory populations of the guppy, poecilia reticulata. the parasite undergoes recurrent epidemic cycles in the host population under conditions of regular immigration of uninfected guppies. during the early phase of the epidemic, heterogeneity among fish together with ... | 1987 | 3614993 |
| detection of sperm within gyrodactylus (platyhelminthes, monogenea) tissues using fluorescence and transmission electron microscopy. | a rapid fluorescent staining method demonstrating spermatozoa within gyrodactylid monogeneans is described. gyrodactylids fixed and stained in 2% acetic acid containing 1 microgram ml-1 bisbenzimide (hoechst 33258) were viewed using epifluorescence microscopy. in addition to staining sperm in the testis, seminal vesicle and seminal receptacle, the technique highlighted sperm in the gut and cytoplasmic lining of the uterus, locations from which they had not previously been recorded. the technique ... | 1997 | 9211503 |
| combined ribosomal dna and morphological analysis of individual gyrodactylid monogeneans. | a method is presented for the isolation and analysis of hamuli, marginal hooks, and bars from individual gyrodactylid monogeneans using scanning electron microscopy (sem), while simultaneously processing parasites for rdna analysis using the polymerase chain reaction (pcr). the haptors of ethanol-fixed gyrodactylids were protease digested to liberate hooks for sem, whereas dna extracted from the bodies was used for pcr. the method resulted in hooks and hamuli being prepared from more than 90% of ... | 1999 | 10219293 |
| parasitized female guppies do not prefer showy males. | in many species male sexual characteristics are known to be affected negatively by parasites, which render their hosts unattractive to females, but how parasites affect the mating decisions of their female hosts has received little attention. the monogenean parasite gyrodactylus turnbulli reduces the sexual display and colour intensity of male guppies, poecilia reticulata, which makes them less attractive to females. here, i examine how these parasites affect the mate choice behaviour of their f ... | 1999 | 10328800 |
| behavior favoring transmission in the viviparous monogenean gyrodactylus turnbulli. | transmission by gyrodactylus turnbulli occurs most frequently when its hosts (poecilia reticulata) come into close contact. this study is the first description of a specific migratory behavior that facilitates transmission of a gyrodactylid from dead hosts. recently-dead guppies typically float at the water's surface; g. turnbulli moves off these fish into the water film, hanging motionless with the haptor held by surface tension. because guppies are surface feeders, detached parasites in the wa ... | 2002 | 12053961 |
| parasitic infections in freshwater ornamental fish in sri lanka. | a total of 1520 ornamental fish of 13 species from 26 export farms in sri lanka were collected between october 1999 and march 2000 and examined for parasites. fish species examined were guppy poecilia reticulata, goldfish carassius auratus, platy xiphophorus maculatus, molly poecilia sphenops, angel pterophyllum scalare, swordtail xiphophorus helleri, tetras hyphessobrycon species, barbs capeota and puntius spp., gourami colisa sp., carp cyprinus carpio, fighters betta spelendens and others (bra ... | 2003 | 12747641 |
| concentration-dependent effects of waterborne zinc on population dynamics of gyrodactylus turnbulli (monogenea) on isolated guppies ( poecilia reticulata ). | the effect of waterborne zinc (zn) on gyrodactylus population dynamics was studied on isolated guppies maintained at concentrations ranging from 0 to 240 microg zn/l. after 1 week pre-exposure to zn, each fish was experimentally infected with 3 gyrodactylids and parasite numbers were recorded daily on each fish until the fish either died or recovered from infection. parasite establishment was most successful at 0 and 240 microg zn/l (97%) compared with the intermediate zn concentrations. low to ... | 2006 | 16197593 |
| effects of waterborne zinc on reproduction, survival and morphometrics of gyrodactylus turnbulli (monogenea) on guppies (poecilia reticulata). | recent reviews indicate that pollutants in the surrounding macroenvironment directly influence the population dynamics, distribution and dispersal of fish ectoparasites, often leading to increased parasitism. the aim of the current study was to explore the effects of sublethal concentrations of waterborne zinc (up to 240 microg zn/l) on survival, reproduction and morphometrics of gyrodactylus turnbulli, a viviparous monogenean infecting the skin and fins of the guppy, poecilia reticulata. parasi ... | 2007 | 17049530 |
| experimental infections of the monogenean gyrodactylus turnbulli indicate that it is not a strict specialist. | parasites represent a threat to endangered fish species, particularly when the parasite can host switch and the new host is vulnerable. if the parasite is highly host specific then successful host switching should be a rare occurrence; however, the host range of many parasites which are assumed to be specialists has never been tested. this includes the monogenean gyrodactylus turnbulli, a well-studied ectoparasite found caudally on its known host, the guppy, poecilia reticulata. in this study, w ... | 2007 | 17224155 |
| experimental infections with the tropical monogenean, gyrodactylus bullatarudis: potential invader or experimental fluke? | introduced exotic species have the potential to spread their associated parasites to native species which can be catastrophic if these hosts are immunologically naïve to the novel parasite. the guppy (poecilia reticulata) has been disseminated worldwide outside of its native habitat and therefore could be an important source of infection to native fish species. its parasite fauna is dominated by the ectoparasitic monogeneans, gyrodactylus turnbulli and gyrodactylus bullatarudis. the current stud ... | 2009 | 19394437 |
| parasite mediated homogenizing selection at the mhc in guppies. | understanding the selective forces influencing genetic diversity is a fundamental goal of evolutionary ecology. the genes of the major histocompatibility complex (mhc) play a key role in the adaptive immune response of vertebrates and thus provide an excellent opportunity to examine the agents of selection on a functionally important gene. here we examine the genetic architecture of the mhc class iib genes in 10 wild populations of guppies (poecilia reticulata) in northern trinidad. we have prev ... | 2010 | 19728113 |
| morphological and molecular taxonomy of a new species of fundulotrema and comments on gyrodactylus stephanus (monogenea: gyrodactylidae) from fundulus heteroclitus (actinopterygii: cyprinodontiformes) in nova scotia, canada. | fundulotrema porterensis n. sp. (monogenea: gyrodactylidae) is described from the mummichog, fundulus heteroclitus (l.; cyprinodontidae), inhabiting porters lake, nova scotia, canada. the new parasite species is characterized by having a ventral bar with small anterolateral processes and linguiform membrane, differentiating it from all other known species of fundulotrema. the morphological description of f. porterensis is supplemented with 1011 sequenced base pairs (bp) of ribosomal dna (rdna) s ... | 2009 | 20049991 |
| sex-specific differences in shoaling affect parasite transmission in guppies. | individuals have to trade-off the costs and benefits of group membership during shoaling behaviour. shoaling can increase the risk of parasite transmission, but this cost has rarely been quantified experimentally. guppies (poecilia reticulata) are a model system for behavioural studies, and they are commonly infected by gyrodactylid parasites, notorious fish pathogens that are directly transmitted between guppy hosts. | 2010 | 20949014 |
| parasite transmission in social interacting hosts: monogenean epidemics in guppies. | infection incidence increases with the average number of contacts between susceptible and infected individuals. contact rates are normally assumed to increase linearly with host density. however, social species seek out each other at low density and saturate their contact rates at high densities. although predicting epidemic behaviour requires knowing how contact rates scale with host density, few empirical studies have investigated the effect of host density. also, most theory assumes each host ... | 2011 | 21897838 |
| a further cost for the sicker sex? evidence for male-biased parasite-induced vulnerability to predation. | males are typically the sicker sex. data from multiple taxa indicate that they are more likely to be infected with parasites, and are less "tolerant," or less able to mitigate the fitness costs of a given infection, than females. one cost of infection for many animals is an increased probability of being captured by a predator. a clear, hitherto untested, prediction is therefore that this parasite-induced vulnerability to predation is more pronounced among males than females. we tested this pred ... | 2016 | 27066240 |
| host heterogeneity affects both parasite transmission to and fitness on subsequent hosts. | infectious disease dynamics depend on the speed, number and fitness of parasites transmitting from infected hosts ('donors') to parasite-naive 'recipients'. donor heterogeneity likely affects these three parameters, and may arise from variation between donors in traits including: (i) infection load, (ii) resistance, (iii) stage of infection, and (iv) previous experience of transmission. we used the trinidadian guppy, poecilia reticulata, and a directly transmitted monogenean ectoparasite, gyroda ... | 2017 | 28289260 |
| the effects of inbreeding on disease susceptibility: gyrodactylus turnbulli infection of guppies, poecilia reticulata. | inbreeding can threaten population persistence by reducing disease resistance through the accelerated loss of gene diversity (i.e. heterozygosity). such inbreeding depression can affect many different fitness-related traits, including survival, reproductive success, and parasite susceptibility. empirically quantifying the effects of inbreeding on parasite resistance is therefore important for ex-situ conservation of vertebrates. the present study evaluates the disease susceptibility of individua ... | 2016 | 27130704 |
| imprinting can cause a maladaptive preference for infectious conspecifics. | recognizing and associating with specific individuals, such as conspecifics or kin, brings many benefits. one mechanism underlying such recognition is imprinting: the long-term memory of cues encountered during development. typically, juveniles imprint on cues of nearby individuals and may later associate with phenotypes matching their 'recognition template'. however, phenotype matching could lead to maladaptive social decisions if, for instance, individuals imprint on the cues of conspecifics i ... | 2016 | 27072405 |
| chronic nitrate enrichment decreases severity and induces protection against an infectious disease. | excessive fertilisation is one of the most pernicious forms of global change resulting in eutrophication. it has major implications for disease control and the conservation of biodiversity. yet, the direct link between nutrient enrichment and disease remains largely unexplored. here, we present the first experimental evidence that chronic nitrate enrichment decreases severity and induces protection against an infectious disease. specifically, this study shows that nitrate concentrations ranging ... | 2016 | 26995268 |
| getting into hot water: sick guppies frequent warmer thermal conditions. | ectotherms depend on the environmental temperature for thermoregulation and exploit thermal regimes that optimise physiological functioning. they may also frequent warmer conditions to up-regulate their immune response against parasite infection and/or impede parasite development. this adaptive response, known as 'behavioural fever', has been documented in various taxa including insects, reptiles and fish, but only in response to endoparasite infections. here, a choice chamber experiment was use ... | 2016 | 26965895 |
| demasculinization of male guppies increases resistance to a common and harmful ectoparasite. | parasites are detrimental to host fitness and therefore should strongly select for host defence mechanisms. yet, hosts vary considerably in their observed parasite loads. one notable source of inter-individual variation in parasitism is host sex. such variation could be caused by the immunomodulatory effects of gonadal steroids. here we assess the influence of gonadal steroids on the ability of guppies (poecilia reticulata) to defend themselves against a common and deleterious parasite (gyrodact ... | 2015 | 26399637 |
| parting ways: parasite release in nature leads to sex-specific evolution of defence. | we evaluated the extent to which males and females evolve along similar or different trajectories in response to the same environmental shift. specifically, we used replicate experimental introductions in nature to consider how release from a key parasite (gyrodactylus) generates similar or different defence evolution in male vs. female guppies (poecilia reticulata). after 4-8 generations of evolution, guppies were collected from the ancestral (parasite still present) and derived (parasite now a ... | 2016 | 26356531 |
| efficacy of commercially available products against gyrodactylus turnbulli infections on guppies poecilia reticulata. | the demand for ornamental fish has led to a steep rise in aquaculture for the hobbyist trade, promoting the emergence, persistence and spread of various infectious diseases. complete control of disease outbreaks with antibiotics and chemical-based medicines is rare, but plant compounds may herald potential alternatives effective against a range of pathogens. melafix® and pimafix® are formulated with the essential oils cajuput (melaleuca cajuputi) and west indian bay (pimenta racemosa) and are ma ... | 2015 | 26203884 |
| efficacy of ginger-based treatments against infection with gyrodactylus turnbulli in the guppy (poecilia reticulata (peters)). | monogenean infections of commercially farmed fishes are responsible for significant economic losses and existing chemical therapeutants, often stressful to the fish, pose associated risks. as part of a recent trend to move towards the use of alternative, plant-based remedies for commonly occurring aquaculture-related diseases, the efficiency of ginger (zingiber officinale) was investigated against the monogenean parasite gyrodactylus turnbulli in the guppy. in vitro trials revealed the clear ant ... | 2015 | 25819871 |
| combined effects of flow condition and parasitism on shoaling behaviour of female guppies poecilia reticulata. | group living in fish can provide benefits of protection from predators and some parasites, more efficient foraging for food, increased mating opportunities and enhanced energetic benefit when swimming. for riverine species, shoaling behaviour can be influenced by various environmental stressors, yet little is known how flow rate might influence the shoaling of diseased fish shoals. in view of the increasingly unpredictable flow rates in streams and rivers, this study aimed to assess the combined ... | 2014 | 25152559 |
| efficacy of garlic based treatments against monogenean parasites infecting the guppy (poecilia reticulata (peters)). | monogenean infections of commercially farmed fishes are responsible for significant economic losses. garlic (allium sativum) is a well-known spice which also possesses anti-microbial and anti-parasitical properties. the current work aimed to test the efficacy of garlic-based treatments against infection with monogenean sp. in the guppy (poecilia reticulata). clipped sections of tail fins of guppies heavily infected with gyrodactylus turnbulli were exposed to aqueous garlic extract (7.5 to 30 ml ... | 2014 | 24598083 |
| fish responses to flow velocity and turbulence in relation to size, sex and parasite load. | riverine fish are subjected to heterogeneous flow velocities and turbulence and may use this to their advantage by selecting regions that balance energy expenditure for station holding while maximizing energy gain through feeding opportunities. this study investigated microhabitat selection by guppies poecilia reticulata in terms of flow characteristics generated by hemisphere boulders in an open channel flume. velocity and turbulence influenced the variation in swimming behaviour with respect t ... | 2014 | 24284893 |
| in vitro and in vivo efficacy of garlic compounds against gyrodactylus turnbulli infecting the guppy (poecilia reticulata). | traditional compounds used to treat fish diseases in aquaculture and the ornamental fish industry (such as formalin and malachite green) can be more toxic to the hosts than their parasites. with the reviviscence in the use of herbal products, various botanicals have been heralded as cures for particular pathogens, but the efficacy of these compounds for parasitic worms is questionable. here, we tested a range of garlic (allium sativum) products against a major aquarium pathogen, gyrodactylus tur ... | 2013 | 24074607 |
| can parasites use predators to spread between primary hosts? | parasites typically have low reproductive fitness on paratenic hosts. such hosts offer other significant inclusive fitness benefits to parasites, however, such as increased mobility and migration potential. the parasite fauna of the guppy (poecilia reticulata) is dominated by the directly transmitted ectoparasites gyrodactylus bullatarudis and gyrodactylus turnbulli. in the wild, close predatory and competitive interactions occur between the guppy and the killifish rivulus hartii. previous obser ... | 2013 | 23714691 |
| relative host body condition and food availability influence epidemic dynamics: a poecilia reticulata-gyrodactylus turnbulli host-parasite model. | understanding disease transmission is important to species management and human health. host body condition, nutrition and disease susceptibility interact in a complex manner, and while the individual effects of these variables are well known, our understanding of how they interact and translate to population dynamics is limited. our objective was to determine whether host relative body condition influences epidemic dynamics, and how this relationship is affected by food availability. poecilia r ... | 2013 | 23122390 |
| interactions between males guppies facilitates the transmission of the monogenean ectoparasite gyrodactylus turnbulli. | in a previous study we found that female guppies shoaled more than males and that there was greater transmission of the ectoparasite gyrodactylus turnbulli between females. here, to test for a possible sex bias in parasite transmission, we conducted a similar experiment on single sex shoals of male and female guppies, observing host behaviour before and after the introduction of an infected shoal mate. the initial parasite burden was considerably lower in the present experiment (30 worms versus ... | 2012 | 23047132 |
| mixed infections and hybridisation in monogenean parasites. | theory predicts that sexual reproduction promotes disease invasion by increasing the evolutionary potential of the parasite, whereas asexual reproduction tends to enhance establishment success and population growth rate. gyrodactylid monogeneans are ubiquitous ectoparasites of teleost fish, and the evolutionary success of the specious gyrodactylus genus is thought to be partly due to their use of various modes of reproduction. gyrodactylus turnbulli is a natural parasite of the guppy (poecilia r ... | 2012 | 22808040 |
| waterborne zinc alters temporal dynamics of guppy poecilia reticulata epidermal response to gyrodactylus turnbulli (monogenea). | the present study assessed the histological changes in the epidermis of poecilia reticulata induced by the combined effects of an ectoparasite gyrodactylus turnbulli and differing concentrations of waterborne zinc (zn). infected guppies were exposed to 0, 15, 30, 60, or 120 µg zn l-1 and monitored over 3 wk during the exponential increase in parasite numbers on the fish. the fish epidermis responded within 3 d to g. turnbulli infection with a rapid increase in epidermal thickness and a modest in ... | 2012 | 22436462 |
| immunogenetic novelty confers a selective advantage in host-pathogen coevolution. | the major histocompatibility complex (mhc) is crucial to the adaptive immune response of vertebrates and is among the most polymorphic gene families known. its high diversity is usually attributed to selection imposed by fast-evolving pathogens. pathogens are thought to evolve to escape recognition by common immune alleles, and, hence, novel mhc alleles, introduced through mutation, recombination, or gene flow, are predicted to give hosts superior resistance. although this theoretical prediction ... | 2018 | 29339521 |
| parasite-mediated host behavioural modifications: gyrodactylus turnbulli infected trinidadian guppies increase contact rates with uninfected conspecifics. | while group formation provides antipredatory defences, increases foraging efficiency and mating opportunities, it can be counterintuitive by promoting disease transmission amongst social hosts. upon introduction of a pathogen, uninfected individuals often modify their social preferences to reduce infection risk. infected hosts also exhibit behavioural changes, for example, removing themselves from a group to prevent an epidemic. conversely, here we show how trinidadian guppies infected with a di ... | 2017 | 29113619 |