| description and proposed life cycle of maritrema novaezealandensis n. sp. (microphallidae) parasitic in red-billed gulls, larus novaehollandiae scopulinus, from otago harbor, south island, new zealand. | maritrema novaezealandensis n. sp. is described from otago harbor, south island, new zealand, on the basis of adult specimens collected from the red-billed gull, larus novaehollandiae scopulinus, and excysted metacercariae obtained from crabs. it belongs to the "eroliae group" and differs from other related species mainly in the shape, size, and patterns of distributions of the spines on the cirrus, the shape of the metraterm, the presence of an unlobed ovary, and the complete ring of the vitell ... | 2004 | 15165049 |
| in vitro cultivation of maritrema novaezealandensis (microphallidae): the effect of culture medium on excystation, survival and egg production. | in this study, the effect of the composition of culture medium on excystation, growth, survival and egg production was investigated for the recently discovered microphallid trematode maritrema novaezealandensis. metacercariae from the two second intermediate crab hosts, macrophthalmus hirtipes and halicarcinus whitei, were incubated in either: (1) 0.85% saline solution, (2) the commercial cell culture medium, nctc-109, (3) nctc-109 supplemented with 20%, or (4) nctc-109 supplemented with 40% chi ... | 2005 | 15682336 |
| larval helminths in intermediate hosts: does competition early in life determine the fitness of adult parasites? | density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. there have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. even if larval parasites suffer a reduction in size, caused by crowding, virtually nothing is known about longer-lasting effects after transmission to the definitive host. this study is the first to use in vitro cultivation with feeding ... | 2005 | 16019005 |
| effects of the trematode maritrema novaezealandensis on the behaviour of its amphipod host: adaptive or not? | there are many recorded cases of parasites that are capable of altering the behaviour of their host to enhance their transmission efficiency. however, not all of these cases are necessarily the results of the parasites actively manipulating host behaviour; they may rather be the 'by-products' of pathology caused by the parasite's presence. this study investigates the effect of the microphallid trematode maritrema novaezealandensis on the behaviour of one of its crustacean intermediate hosts, the ... | 2006 | 16923271 |
| diversity of trematode genetic clones within amphipods and the timing of same-clone infections. | the genetic diversity of trematodes within second intermediate hosts has important implications for the evolution of trematode populations as these hosts are utilized after the parasites reproduce asexually within first intermediate hosts and before sexual reproduction within definitive hosts. we characterised the genetic clonal diversity of the marine trematode maritrema novaezealandensis within amphipod (paracalliope novizealandiae) second intermediate hosts using four to six microsatellite lo ... | 2007 | 17188274 |
| clonal diversity of the marine trematode maritrema novaezealandensis within intermediate hosts: the molecular ecology of parasite life cycles. | we quantified the clonal diversity of the new zealand marine trematode maritrema novaezealandensis (n = 1250) within zeacumantus subcarinatus snail (n = 25) and macrophthalmus hirtipes crab (n = 25) intermediate hosts using four to six microsatellite loci, and investigated the potential biological and physical factors responsible for the observed genetic patterns. individual snails harboured one to five trematode genotypes and 48% of snails were infected by multiple parasite genotypes. overall, ... | 2007 | 17217355 |
| effects of interspecific competition on asexual proliferation and clonal genetic diversity in larval trematode infections of snails. | interactions among different parasite species within hosts can be important factors shaping the evolution of parasite and host populations. within snail hosts, antagonistic interactions among trematode species, such as competition and predation, can influence parasite abundance and diversity. in the present study we examined the strength of antagonistic interactions between 2 marine trematodes (maritrema novaezealandensis and philophthalmus sp.) in naturally infected zeacumantus subcarinatus sna ... | 2008 | 18442429 |
| the use of fluorescent fatty acid analogs as labels in trematode experimental infections. | we examined the utility of fluorescent fatty acid analog dyes for labeling larval trematodes to use in experimental infections. our goals were to identify two dyes that label larval trematodes belonging to the species maritrema novaezealandensis and coitocaecum parvum, determine if the dyes influence survival and infectivity of larval trematodes and/or host mortality, and if larval trematodes labeled with alternative dyes could be distinguished post-infection. the two dyes tested, bodipy fl c(12 ... | 2008 | 18508051 |
| the influence of clonal diversity and intensity-dependence on trematode infections in an amphipod. | individual animals are often infected not only by different parasite species, but also by multiple genotypes of the same parasite species. genetic relatedness among parasites sharing a host is expected to modulate their strategies of resource exploitation, growth and virulence. we experimentally examined the effects that genetic diversity and infection intensity had on host mortality, infectivity and growth of the marine trematode maritrema novaezealandensis in amphipod hosts. the presence of 2 ... | 2009 | 19154642 |
| causes of intraspecific variation in body size among trematode metacercariae. | inequalities in body size among adult helminths can result in inequalities in reproductive output, with consequences for population dynamics and genetics. these inequalities can result from growth differences among larval worms inside intermediate hosts that persist into the adult stage. here, we investigate the effects of both host body size and intensity of infection on the sizes of metacercariae of the trematode maritrema novaezealandensis (microphallidae) inside their second intermediate hos ... | 2009 | 19216824 |
| interspecific and intraspecific variation in cercariae release. | given the importance of temperature for the shedding of trematode infective stages (cercariae) from gastropod first intermediate hosts, we investigated the response to temperature increases of trematodes of the intertidal snail zeacumantus subcarinatus collected from different latitudes (differing in mean annual summer temperature) on the south island of new zealand. we investigated whether shedding of cercariae at elevated temperatures differed both between species (interspecific variation) and ... | 2009 | 19245275 |
| effects of temperature, salinity, and water level on the emergence of marine cercariae. | with the prospect of large-scale environmental changes, there is an urgent need to obtain information regarding environmental influences acting on the emergence of cercariae in marine systems. we investigated the response of trematodes of the intertidal snail zeacumantus subcarinatus to altered temperature, salinity, and water level. the emergence of one trematode species, maritrema novaezealandensis (microphallidae), showed a weak trend to decrease with increased temperature; whereas, the emerg ... | 2009 | 19475423 |
| contrasting mtdna diversity and population structure in a direct-developing marine gastropod and its trematode parasites. | the comparative genetic structure of hosts and their parasites has important implications for their coevolution, but has been investigated in relatively few systems. in this study, we analysed the genetic structure and diversity of the new zealand intertidal snail zeacumantus subcarinatus (n = 330) and two of its trematode parasites, maritrema novaezealandensis (n = 269) and philophthalmus sp. (n = 246), using cytochrome c oxidase subunit i gene (coi) sequences. snails and trematodes were examin ... | 2009 | 19845857 |
| spatial variation in parasite-induced mortality in an amphipod: shore height versus exposure history. | characterizing the causes of spatial and temporal variation in parasite-induced mortality under natural conditions is crucial to better understanding the factors driving host population dynamics. our goal was to quantify this variation in the amphipod paracalliope novizealandiae, a second intermediate host of the trematode, maritrema novaezealandensis. if infection and development of trematode metacercariae are benign, we expected mature metacercariae to accumulate within amphipods inhabiting hi ... | 2010 | 20217140 |
| genetic and environmental determinants of host use in the trematode maritrema novaezealandensis (microphallidae). | factors constraining host specificity are poorly understood. intraspecific variation in host preferences in generalist parasites may reveal which factors affect patterns of host use, and thus the evolution of specialization. here, laboratory experiments examined genetic variation in host preferences and the effect of a refugium against infection on host use. firstly, 6 cercarial clones of the trematode maritrema novaezealandensis (ranging widely in heterozygosities) were exposed simultaneously t ... | 2011 | 20663252 |
| host partitioning by parasites in an intertidal crustacean community. | patterns of host use by parasites throughout a guild community of intermediate hosts can depend on several biological and ecological factors, including physiology, morphology, immunology, and behavior. we looked at parasite transmission in the intertidal crustacean community of lower portobello bay, dunedin, new zealand, with the intent of: (1) mapping the flow of parasites throughout the major crustacean species, (2) identifying hosts that play the most important transmission role for each para ... | 2010 | 20950092 |
| permanent genetic resources added to molecular ecology resources database 1 january 2009-30 april 2009. | this article documents the addition of 283 microsatellite marker loci to the molecular ecology resources database. loci were developed for the following species: agalinis acuta; ambrosia artemisiifolia; berula erecta; casuarius casuarius; cercospora zeae-maydis; chorthippus parallelus; conyza canadensis; cotesia sesamiae; epinephelus acanthistius; ficedula hypoleuca; grindelia hirsutula; guadua angustifolia; leucadendron rubrum; maritrema novaezealandensis; meretrix meretrix; nilaparvata lugens; ... | 2009 | 21564911 |
| in vitro culture of marine trematodes from their snail first intermediate host. | the ability to culture parasites outside their host (i.e. in vitro) is essential for several aspects of parasitological research. here, a culture medium for marine trematode parthenitae was optimized using philophthalmus sp. rediae from the intermediate snail host, zeacumantus subcarinatus. the medium was optimized by sequentially testing the suitability of different levels of osmolality, different commercially available media, and different concentrations of supplemented chicken serum, while co ... | 2011 | 21801722 |
| small worms, big appetites: ratios of different functional morphs in relation to interspecific competition in trematode parasites. | animals living in colonies or collectives composed of highly-related individuals often produce morphs that are physically and behaviourally specialised to perform specific tasks. because such morphs are often sterile, their production represents a fitness cost for the colony and there should be an optimal ratio of the numbers of sterile specialists and reproductive members that may be adjustable to environmental conditions. trematode parasites undergo asexual multiplication within their snail in ... | 2011 | 21683703 |
| genetic and phenotypic influences on clone-level success and host specialization in a generalist parasite. | studying resource specialization at the individual level can identify factors constraining the evolution of generalism. we quantified genotypic and phenotypic variability among infective stages of 20 clones of the parasitic trematode maritrema novaezealandensis and measured their infection success and post-infection fitness (growth, egg output) in several crabs and amphipods. first, different clones varied in their infection success of different crustaceans. second, neither genetic nor phenotypi ... | 2012 | 22022929 |
| clone-specific immune reactions in a trematode-crustacean system. | summaryvariability of immune responses is an essential aspect of ecological immunology, yet how much of this variability is due to differences among parasite genotypes remains unknown. here, variation in immune response of the crab, macrophthalmus hirtipes, is examined as a function of experimental exposure to 10 clonal cercarial lineages of the trematode maritrema novaezealandensis. our goals were (1) to assess the variability of the h ... | 2011 | 21996534 |
| effects of ultraviolet radiation on the transmission process of an intertidal trematode parasite. | summarythe transmission of parasites takes place under exposure to a range of fluctuating environmental factors, one being the changing levels of solar ultraviolet radiation (uvr). here, we investigated the effects of ecologically relevant levels of uvr on the transmission of the intertidal trematode maritrema novaezealandensis from its first intermediate snail host (zeacumantus subcarinatus) to its second intermediate amphipod host (paracalliope novizealandiae). we assessed the output of parasi ... | 2012 | 22216919 |
| m aritrema corai n. sp. (digenea: microphallidae) from the white ibis eudocimus albus (linnaeus) (aves: threskiornithidae) in mexico. | m aritrema corai n. sp. is described based on material from the intestine of the white ibis eudocimus albus (l.) (threskiornithidae) in mexico. the new species can be distinguished morphologically from all congeners by the unique combination of the following morphological features: a very long cirrus sac attenuated distally [cirrus sac to body length ratio 1:0.90-1.29 (mean 1:1.07)]; a large, elongate-oval seminal receptacle, located dorsally between the cirrus sac and ovary; and long, filiform, ... | 2016 | 26453094 |
| variation among genotypes in responses to increasing temperature in a marine parasite: evolutionary potential in the face of global warming? | climates are changing worldwide, and populations are under selection to adapt to these changes. changing temperature, in particular, can directly impact ectotherms and their parasites, with potential consequences for whole ecosystems. the potential of parasite populations to adapt to climate change largely depends on the amount of genetic variation they possess in their responses to environmental fluctuations. this study is, to our knowledge, the first to look at differences among parasite genot ... | 2014 | 25066543 |
| two new species of maritrema nicoll, 1907 (digenea: microphallidae) from new zealand: morphological and molecular characterisation. | two new species of the microphallid genus maritrema (maritrema) nicoll, 1907 are described from freshwaters in the south island of new zealand. maritrema deblocki n. sp. occurs as an adult in the mallard anas platyrhynchos (l.); maritrema poulini n. sp. is found as sporocysts/cercariae in potamopyrgus antipodarum (gray) and as metacercariae in two species of amphipod and two species of isopod. we use morphological and molecular characterisation to distinguish between the two species, and compare ... | 2014 | 24562817 |
| reproduction and caste ratios under stress in trematode colonies with a division of labour. | trematodes form clonal colonies in their first intermediate host. individuals are, depending on species, rediae or sporocysts (which asexually reproduce) and cercariae (which develop within rediae or sporocysts and infect the next host). some species use a division of labour within colonies, with 2 distinct redial morphs: small rediae (non-reproducing) and large rediae (individuals which produce cercariae). the theory of optimal caste ratio predicts that the ratio of caste members (small to larg ... | 2013 | 23442525 |
| local effects of a global problem: modelling the risk of parasite-induced mortality in an intertidal trematode-amphipod system. | the interactive effects of climate change and parasitism are of concern because of potentially important consequences for host populations, communities and entire ecosystems. in marine environments, the absence of historic baseline data on parasitism and disease limits our ability to make realistic predictions about these consequences. here, we adapt a simulation model developed for a northern hemisphere intertidal host-parasite system to a comparable system in the southern hemisphere. the entir ... | 2013 | 23355061 |
| caste ratios affect the reproductive output of social trematode colonies. | intraspecific phenotypic diversification in social organisms often leads to formation of physical castes which are morphologically specialized for particular tasks within the colony. the optimal caste allocation theory argues that specialized morphological castes are efficient at specific tasks, and hence different caste ratios should affect the ergonomic efficiency, hence reproductive output of the colony. however, the reproductive output of different caste ratios has been documented in few spe ... | 2013 | 23252707 |
| cercarial survival in an intertidal trematode: a multifactorial experiment with temperature, salinity and ultraviolet radiation. | parasite transmission takes place in the context of a multitude of simultaneously fluctuating environmental factors. as a particularly vulnerable step in the transmission, trematode cercariae are directly exposed to ambient conditions during their search for a host. here, we investigated the survival of cercariae of the intertidal trematode maritrema novaezealandensis in a multifactorial experiment (2 × 2 × 2 design) with temperature (20 and 30 °c), salinity (35 and 40 practical salinity units ( ... | 2013 | 23052764 |
| fitness benefits of a division of labour in parasitic trematode colonies with and without competition. | a reproductive division of labour has recently been discovered within polyembryonic colonies of two species of parasitic trematodes infecting snail hosts. in these colonies, one morph expands the colony through asexual reproduction while the other morph never reproduces. as in other polyembryonic species using a division of labour (parasitoid wasps, one species of sea anemone), the non-reproducing morph appears specialized for defense against competing colonies. in this study, we first assessed ... | 2012 | 22935097 |
| effects of ultraviolet radiation on an intertidal trematode parasite: an assessment of damage and protection. | trematode parasites are integral components of intertidal ecosystems which experience high levels of ultraviolet radiation. although these parasites mostly live within hosts, their life cycle involves free-living larval transmission stages such as cercariae which are directly exposed to ambient conditions. uv has previously been shown to considerably reduce the survival of cercariae. here, we investigated potential mechanisms of protection and damage related to uv in the intertidal trematode mar ... | 2012 | 22787586 |