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opencc-zeroJan 2024View details →

Data from: Parasite-mediated changes in host traits alter food web dynamics

Parasites commonly alter the phenotype of their host, thereby influencing competitive and consumer-resource interactions. This could trigger a cascade effect on the dynamics of biological communities, but the role of parasites in ecosystem processes is poorly understood. In this study, we investigate how parasite-induced trait modifications shape the dynamics of a complex lake food web using an allometric trophic network model (ATN). We simulated infections of stage-structured fish host populations via increased maintenance costs and predation risk. Our results show that host trait modifications can significantly impact host demography, with stage-specific biomass declines up to 60%. However, less severely affected host stages buffered these effects and sustained the population. Importantly, host biomass decline altered the dynamics of species interactions and these effects cascaded through the entire community, with biomass changes observed at all trophic levels. Our findings emphasize the importance of incorporating both indirect parasite effects and host life history in ecological network studies for more realistic simulations of community dynamics.

opencc-zeroJan 2024View details →

Bloodmeal metabarcoding of the argasid tick (Ornithodoros turicata Dugès) reveals extensive vector-host associations

Molecular methods to understand host feeding patterns of arthropod vectors are critical to assess exposure risk to vector-borne disease and unveil complex ecological interactions. We build on our prior work discovering the utility of PCR-Sanger sequencing bloodmeal analysis that work well for soft ticks (Acari: Argasidae), unlike for hard ticks (Acari: Ixodidae), thanks to their unique physiology that retains prior bloodmeals for years. Here, we apply bloodmeal metabarcoding using amplicon deep sequencing to identify multiple host species in individual Ornithodoros turicata soft ticks collected from two natural areas in Texas, United States. Of 788 collected O. turicata, 394 were evaluated for bloodmeal source via metabarcoding, revealing 27 different vertebrate hosts (17 mammals, 5 birds, 1 reptile, and 4 amphibians) fed upon by 274 soft ticks. Information on multiple hosts was derived from 167 individual O. turicata (61%). Metabarcoding revealed mixed vertebrate bloodmeals in O. turicata while same specimens yielded only one vertebrate species using Sanger sequencing. These data reveal wide host range of O. turicata and demonstrate the value of bloodmeal metabarcoding for understanding the ecology for known and potential tick-borne pathogens circulating among humans, domestic animals and wildlife such as relapsing fever caused by Borrelia turicatae. Our results also document evidence of prior feeding on wild pig from an off-host soft tick for the first time in North America; a critical observation in the context of enzootic transmission of African swine fever virus if it were introduced to the US. This research enhances our understanding of vector-host associations and offers a promising perspective for biodiversity monitoring and disease control strategies.

opencc-zeroFeb 2024View details →

Energy input, habitat heterogeneity, and host specificity on avian haemosporidian diversity at continental scales

The correct identification of biotic and abiotic drivers affecting parasite diversity and assemblage composition at different spatial scales is crucial for understanding how pathogen distribution responds to anthropogenic disturbance and climate change. Here, we used a database of avian haemosporidian parasites to identify such drivers and their effect on the taxonomic and phylogenetic diversity of genera Plasmodium, Haemoproteus, and Leucocytozoon from three zoogeographic regions. We explored how parasite diversity is related to energy input (i.e., temperature, precipitation, and potential evapotranspiration [PET]), to habitat heterogeneity (i.e., climatic seasonality, vegetation density, ecosystem heterogeneity, human disturbance, and host richness), and to a novel assemblage-level metric related to parasite niche overlap (degree of generalism). We found that the relative importance of the predictors differed between the three studied parasite genera and across diversity metrics. Among the most consistent predictors, host richness was positively related to the taxonomic diversity of the three genera. Energy input and human footprint explained the phylogenetic diversity of Haemoproteus. Finally, the degree of generalism explained the diversity of Plasmodium and Leucocytozoon. Our results suggest that different dimensions of haemosporidian diversity are shaped by energy input, host heterogeneity, and assembly processes related to parasite resource use within local parasite assemblages.

Fig. 2 in Host-adapted Cryptosporidium and Enterocytozoon bieneusi genotypes in straw-colored fruit bats in Nigeria

Fig. 2. Genotyping of Cryptosporidium spp. in strawcolored fruit bats by small subunit rRNA-based PCRRFLP. Upper panel: SspI RFLP patterns; lower panel: VspI RFLP patterns; M: 100-bp molecular markers; H: C. hominis positive control; P: C. parvum positive control; B1: Cryptosporidium bat genotype XIV; B2: Cryptosporidium bat genotype XV.

Fig. 4 in Host-adapted Cryptosporidium and Enterocytozoon bieneusi genotypes in straw-colored fruit bats in Nigeria

Fig. 4. Phylogeny of Enterocytozoon bieneusi genotypes in bats based on Bayesian inference analysis of sequences of the internal transcribed spacer of the rRNA gene. The posterior probability values are indicated on the branches. Red ones are E. bieneusi genotypes identified in straw-colored fruit bats in the present study. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

opencc-zeroFeb 2024View details →

Data for: Biomechanical adaptations enable phoretic mite species to occupy distinct spatial niches on host burying beetles

Niche theory predicts that ecologically similar species coexist by minimising interspecific competition through niche partitioning. Therefore understanding the mechanisms of niche partitioning is essential for predicting interactions and coexistence between competing organisms. Here we study two phoretic mite species, Poecilochirus carabi, and Macrocheles nataliae that coexist on the same host-burying beetle Nicrophorus vespilloides and use it to 'hitchhike' between reproductive sites. Field observations revealed clear spatial partitioning between species in distinct host body parts. P. carabi preferred the ventral side of the thorax, whereas M. nataliae were exclusively found ventrally at the hairy base of the abdomen. Experimental manipulations of mite density showed that each species preferred these body parts, largely regardless of the density of the other mite species on the host beetle. Force measurements indicated that this spatial distribution is mediated by biomechanical adaptations, because each mite species required more force to be removed from their preferred location on the beetle. While P. carabi attached with large adhesive pads to the smooth thorax cuticle, M. nataliae gripped abdominal setae with their chelicerae. Our results show that specialist biomechanical adaptations for attachment can mediate spatial niche partitioning among species sharing the same host.

Figure 4 in New records of the shrimp Periclimenes crinoidalis Chace, 1969 (Decapoda: Palaemonidae) and its crinoid host Nemaster grandis A.H. Clark, 1909 (Echinodermata: Crinoidea) in the Caribbean Sea

Figure 4. Male of Periclimenes crinoidalis (CL 1.58 mm), associated with the crinoid Nemaster cf. grandis, in Chichiriviche de la Costa, Vargas State, Venezuela.

Figure 3 in New records of the shrimp Periclimenes crinoidalis Chace, 1969 (Decapoda: Palaemonidae) and its crinoid host Nemaster grandis A.H. Clark, 1909 (Echinodermata: Crinoidea) in the Caribbean Sea

Figure 3. Ovigerous female of Periclimenes crinoidalis (CL 2.36 mm), associated with the crinoid Nemaster grandis, in Chichiriviche de la Costa, Vargas State, Venezuela.

Figure 2 in New records of the shrimp Periclimenes crinoidalis Chace, 1969 (Decapoda: Palaemonidae) and its crinoid host Nemaster grandis A.H. Clark, 1909 (Echinodermata: Crinoidea) in the Caribbean Sea

Figure 2. Mimicry of the shrimp Periclimenes crinoidalis associated with the crinoid Nemaster cf. grandis, in Chichiriviche de la Costa, Vargas State, Venezuela.

opencc-zeroFeb 2024View details →

Data from: In vitro competition between two transmissible cancers, and potential implications for their host, the Tasmanian devil

Since the emergence of a transmissible cancer, devil facial tumour disease (DFT1), in the 1980s, wild Tasmanian devil populations have been in decline. In 2016, a second, independently evolved transmissible cancer (DFT2) was discovered raising concerns for survival of the host species. Here, we applied experimental and modelling frameworks to examine competition dynamics between the two transmissible cancers in vitro. Using representative cell lines for DFT1 and DFT2, we have found that in monoculture, DFT2 grows twice as fast as DFT1 but reaches lower maximum cell densities. Using co-cultures, we demonstrate that DFT2 outcompetes DFT1: the number of DFT1 cells decreasing over time, never reaching exponential growth. This phenomenon could not be replicated when cells were grown separated by a semi-permeable membrane, consistent with exertion of mechanical stress on DFT1 cells by DFT2. A logistic model and a Lotka-Volterra competition model were used to interrogate monoculture and co-culture growth curves respectively, suggesting DFT2 is a better competitor than DFT1, but also showing that competition outcomes might depend on the initial number of cells, at least in the laboratory. We provide theories how the in vitro results could be translated to observations in the wild and propose that these results may indicate that although DFT2 is currently in a smaller geographic area than DFT1, it could have the potential to outcompete DFT1. Further, we provide a framework for improving the parameterization of epidemiological models applied to these cancer lineages, which will inform future disease management.

opencc-by-4.0Dec 2023View details →

Figure 1 in Contribution to the knowledge of Parichoronyssus bakeri Morales-Malacara and Guerrero, 2007 (Mesostigmata: Macronyssidae): new locality and host-association records with additional molecular data

Figure 1 Light Microscopy images of the female Parichoronyssus bakeri. A – General view of the ventral idiosoma; B – General view of the dorsal idiosome; C – Close up of sternal shield; D – Close up of genital and anal shields; E – Gnathosoma and coxa of the Leg I, with the black arrow pointed out the spine-like projection; F – Close up of the dorsal shield. Scales: A and B 50µm, C-F 20µm.

opencc-zeroMar 2024View details →

Contrasting effects of host or local specialization: widespread haemosporidians are host generalist whereas local specialists are locally abundant

Aim: Despite the wide distribution of many parasites around the globe, the range of individual species varies significantly even among phylogenetically related taxa. Since parasites need suitable hosts to complete their development, parasite geographical and environmental ranges should be limited to communities where their hosts are found. Parasites may also suffer from a trade-off between being locally abundant or widely dispersed. We hypothesize that the geographical and environmental ranges of parasites are negatively associated to their host specificity and their local abundance. Location: Worldwide Time period: 2009 to 2021 Major taxa studied: Avian haemosporidian parasites Methods: We tested these hypotheses using a global database which comprises data on avian haemosporidian parasites from across the world. For each parasite lineage, we computed five metrics: phylogenetic host-range, environmental range, geographical range, and their mean local and total number of observations in the database. Phylogenetic generalized least squares models were ran to evaluate the influence of phylogenetic host-range and total and local abundances on geographical and environmental range. In addition, we analysed separately the two regions with the largest amount of available data: Europe and South America. Results: We evaluated 401 lineages from 757 localities and observed that generalism (i.e. phylogenetic host range) associates positively to both the parasites' geographical and environmental ranges at global and Europe scales. For South America, generalism only associates with geographical range. Finally, mean local abundance (mean local number of parasite occurrences) was negatively related to geographical and environmental range. This pattern was detected worldwide and in South America, but not in Europe. Main Conclusions: We demonstrate that parasite specificity is linked to both their geographical and environmental ranges. The fact that locally abundant parasites present restricted ranges, indicates a trade-off between these two traits. This trade-off, however, only becomes evident when sufficient heterogeneous host communities are considered.

opencc-zeroMar 2024View details →

The impact of within-host coinfection interactions on between-host parasite transmission dynamics varies with spatial scale

Within-host interactions among coinfecting parasites can have major consequences for individual infection risk and disease severity. However, the impact of these within-host interactions on between-host parasite transmission, and the spatial scales over which they occur, remain unknown. We developed and applied a novel spatially explicit analysis to parasite infection data from a wild wood mouse (Apodemus sylvaticus) population. We previously demonstrated a strong within-host negative interaction between two wood mouse gastrointestinal parasites, the nematode Heligmosomoides polygyrus, and the coccidian Eimeria hungaryensis, using drug-treatment experiments. Here, we show this negative within-host interaction can significantly alter the between-host transmission dynamics of E. hungaryensis, but only within spatially-restricted neighbourhoods around each host. However, for the closely related species E. apionodes, which experiments show does not interact strongly with H. polygyrus, we did not find any effect on transmission over any spatial scale. Our results demonstrate that the effects of within-host coinfection interactions can ripple out beyond each host to alter the transmission dynamics of the parasites, but only over local scales that likely reflect the spatial dimension of transmission. Hence there may be knock-on consequences of drug treatments impacting the transmission of non-target parasites, altering infection risks even for non-treated individuals in the wider neighbourhood.

Fig. 4 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 4. Schematic drawings of different shapes of MCO of the current Pseudempleurosoma haywardi specimens. Scale bar = 10 µm.

Fig. 1 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 1. Schematic measurement characteristics of the organs of Pseudempleurosoma haywardi. A, MCO with Accessory piece; B, egg; C, muscular genital atrium; D, ovary; E, testis; F, dorsal anchors; G, dorsal bar; H, ventral anchor with attached ventral bar; I, detached ventral bar; J, marginal hook. Abbreviations used: APL: accessory piece length, AVBL: attached ventral bar length, DAL: dorsal anchor length, DBL: dorsal bar length, DBW: dorsal bar width, DVBL: detached ventral bar length, EL: egg length, EW: egg width, MAL: muscular genital atrium length, MAW: muscular genital atrium width, MCO: male copulatory organ, MCOL: male copulatory organ length, MHL: marginal hook length, OL: ovary length, OW: ovary width, TL: testis length, TW: testis width, VAL: ventral anchor length.

Fig. 3 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 3. Schematic drawings of Pseudempleurosoma haywardi. A, whole body; B, MCO; C, ventral anchor with attached ventral bar; D, marginal hooks; E, dorsal anchor; F, egg; G, detached ventral bar; H, dorsal bar. Scale bars: A = 500 µm; B–H = 10 µm.

Fig. 2 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 2. General morphology of Pseudempleurosoma haywardi under phase-contrast microscope (A, B) and light microscope (C–G). A, whole body; B, opisthaptor part; C, opisthaptor with anchors, bar and marginal hooks; D, egg with MCO; E, egg; F, funnel-shaped of MCO with accessory pieces; G, cup-shaped MCO with accessory pieces. Abbreviations used: ASP: accessory piece, AVB: attached ventral bar, DA: dorsal anchor, DB: dorsal bar, DVB: detached ventral bar, E: egg, ES: eye spot, HG: head glands, MCO: male copulatory organ, MH: marginal hook, OP: opisthaptor, P: pharynx, VA: ventral anchor, VF: vitelline follicles. Scale bars: A = 100 µm; B–G = 20 µm.

Fig. 6 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 6. Phylogenetic tree of partial 28S rRNA of monogeneans based on Maximum Likelihood methods. Two major Clades A and B are distinguished. External branches with and without round tips represent members of Dactylogyridae and Ancyrocephalidae, respectively (when classified following the NCBI database), except for the outgroup. Bootstrap support values are indicated at each node. Monogenean sequence data from this study are shown in bold. Scale bar represents the number of nucleotide substitutions per site.

Fig. 5 in New record of endoparasitic Pseudempleurosoma haywardi (Monogenea: Dactylogyridae) in sillaginid fishes from Thailand, with updates on host range, zoogeography, and morphological variation

Fig. 5. General morphology of the infected sillaginid fishes, (A) Sillago aeolus and (B) Sillago sihama. Scale bars = 1 cm.

Fig. 4 in Hamatospiculum flagellispiculosum (Nematoda: Diplotriaenidae) causing severe disease in a new host from Argentine Patagonia: Campephilus magellanicus (Aves: Picidae)

Fig. 4. Optical microscope micrograph of histopathological assessment of muscular tissues dissected from articulations affected by a parasitic infection in Campephilus magellanicus: (A) Sample from the right knee exhibiting loss of the skeletal muscle architecture and nematode eggs (dark dots at lower half), contiguous to muscle fibers with normal tissue architecture (upper half), Bar = 200 μm. (B) Sample from the left tibiotarsus mass showing myofibers of variable shape and size, diffuse mononuclear infiltration, and several eggs, Bar = 100 μm. (C) Two thin-shelled eggs with fully differentiated L1 at the centre of the image, surrounded by mononuclear cells, Bar = 20 μm.