Evolution of parasites in the Anthropocene: new pressures, new adaptive directions.

The Anthropocene is seeing the human footprint rapidly spreading to all of Earth's ecosystems. The fast-changing biotic and abiotic conditions experienced by all organisms are exerting new and strong selective pressures, and there is a growing list of examples of human-induced evolution in response to anthropogenic impacts. No organism is exempt from these novel selective pressures.

New insights into avian malaria infections in New Zealand seabirds.

The past few years have been marked by a drastic increase in pathogen spillover events. However, the extent and taxonomic range at which these events take place remain as crucial unanswered questions in many host-pathogen systems. Here, we take advantage of opportunistically sampled bird carcasses from the South Island of New Zealand, with the aim of identifying Plasmodium spp.

Description and molecular data of a new cestode parasite, Cladotaenia anomala n. sp. (Paruterinidae) from the Australasian harrier (Circus approximans Peale) in New Zealand.

Currently comprising 12 species infecting the gastrointestinal tracts of diurnal raptors (Falconiformes, Accipitriformes), species of Cladotaenia are diagnosed by their branching uterus, testes in two fields reaching the same level anteriorly, and small rostellum armed with taenioid hooks arranged in two rows. In this study we describe a new species of Cladotaenia recovered from a number of Australasian harriers Circus approximans, from the southern half of South Island, New Zealand. The new species is distinguished from other species by its single circle of hooks.

Gastrointestinal helminths of the Australasian harrier ( Peale, 1848) in New Zealand, and description of a new species of nematode, n. sp. (Habronematidae).

The Australasian harrier , a native of Australia, New Zealand and the South Pacific, is an opportunistic hunter of small prey, although a large part of its diet consists of carrion, mainly from roadkill. Besides a record of a single, unnamed species of capillariid nematode there have been no investigations into the parasites of Australasian harriers in New Zealand. In this study, a helminthological survey of sixty-five deceased harriers from southern New Zealand uncovered a gastrointestinal helminth fauna consisting of six parasite species.

Description and molecular data for a new acanthocephalan parasite, Polymorphus circi n. sp. (Polymorphidae) from the Australasian harrier (Circus approximans Peale) in New Zealand.

Species of genus Polymorphus Lühe, 1911 (Polymorphidae) are acanthocephalans found in fish-eating birds and waterfowl. Although found in many parts of the world, including Australia, no records exist from New Zealand. Because of the largely aquatic intermediate host, Polymorphus species are rarely found in terrestrial birds of prey.

Physical evidence of direct antagonistic interactions between trematodes in the host gut: the kiss of death?

Although within-host competition among parasites if often assumed to occur based on statistical patterns, actual physical evidence of direct antagonistic interactions between parasites, either intraspecific or interspecific, is very rare. Here, we report such evidence between and within two species of hemiurid trematodes infecting the deep-sea grenadier fish Coryphaenoides subserrulatus. We found pairs of worms attached together, with one worm using its ventral sucker against another worm, and sucking out a large protuberance on the victim.

Biases in parasite biodiversity research: why some helminth species attract more research than others.

As the number of known and described parasite species grows every year, one might ask: how much do we actually know about these species beyond the fact they exist? For free-living taxa, research effort is biased toward a small subset of species based on their properties or human-centric factors. Here, using a large data set on over 2500 helminth parasite species described in the past two decades, we test the importance of several predictors on two measures of research effort: the number of times a species description is cited following its publication, and the number of times a species' name is mentioned in the scientific literature. Our analysis highlights some taxonomic biases: for instance, descriptions of acanthocephalans and nematodes tend to receive more citations than those of other helminths, and species of cestodes are less frequently mentioned in the literature than other helminths.

Battle of the sexes: analysis of sex bias in host use and reporting practices in parasitological experiments.

Experimental approaches are among the most powerful tools available to biologists, yet in many disciplines their results have been questioned due to an underrepresentation of female animal subjects. In parasitology, experiments are crucial to understand host-parasite interactions, parasite development, host immune responses, as well as the efficacy of different control methods. However, distinguishing between species-wide and sex-specific effects requires the balanced inclusion of both male and female hosts in experiments and the reporting of results for each sex separately.

Tracking life cycles of parasites across a broad taxonomic scale in a marine ecosystem.

Parasitic helminths exhibit remarkable diversity in their life cycles, although few parasite species have their whole life cycles resolved. Owing to the fact that parasite life stages within hosts are often not comparable using morphological data, genetic data provides convincing evidence of transmission pathways between intermediate and definitive hosts. We took this approach to an ecosystem level, genetically matching parasite (acanthocephalan, cestode, nematode and trematode) life stages across a broad taxonomic range of intermediate and definitive hosts (invertebrates, seabirds, elasmobranchs and teleost fish) in Otago's (New Zealand) coastal marine ecosystem.

Assigning cause for emerging diseases of aquatic organisms.

Resolving the cause of disease (= aetiology) in aquatic organisms is a challenging but essential goal, heightened by increasing disease prevalence in a changing climate and an interconnected world of anthropogenic pathogen spread. Emerging diseases play important roles in evolutionary ecology, wildlife conservation, the seafood industry, recreation, cultural practices, and human health. As we emerge from a global pandemic of zoonotic origin, we must focus on timely diagnosis to confirm aetiology and enable response to diseases in aquatic ecosystems.

Large-scale genetic investigation of nematode diversity and their phylogenetic patterns in New Zealand's marine animals.

Nematodes constitute one of the most speciose metazoan groups on earth, and a significant proportion of them have parasitic life styles. Zooparasitic nematodes have zoonotic, commercial and ecological significance within natural systems. Due to their generally small size and hidden nature within their hosts, and the fact that species discrimination using traditional morphological characteristics is often challenging, their biodiversity is not well known, especially within marine ecosystems.

Male-biased selection of holotypes in parasite taxonomy: is it justified?

When a new parasite species is identified, a name-bearing specimen or holotype is designated as its reference standard. For most acanthocephalans and nematodes, the holotype is male, a bias which lacks scientific justification. We propose ways of redressing this imbalance and achieving fuller representation of each species in museum collections.

Decay of parasite community similarity with host phylogenetic and geographic distances among deep-sea fish (grenadiers).

Although parasite community studies are growing in numbers, our understanding of which macro-ecological and evolutionary processes have shaped parasite communities is still based on a narrow range of host–parasite systems. The present study assessed the diversity and endoparasite species composition in New Zealand deep-sea fish (grenadiers, family Macrouridae), and tested the effects of host phylogeny and geography on the structure of endoparasite communities using a distance decay framework. We found that grenadiers from the Chatham Rise harboured a surprisingly high diversity of digeneans, cestodes and nematodes, with different species of grenadiers having different parasite assemblages.

Gastrointestinal helminth parasites of the threatened Australasian crested grebe (Podiceps cristatus australis, Gould 1844) in New Zealand, with descriptions of Baruscapillaria kamanae n. sp. (Nematoda: Trichuridae) and Cryptocotyle micromorpha n. sp. (Trematoda: Opisthorchiidae).

The Australasian crested grebe Podiceps cristatus australis, Gould 1844 is restricted to Australia and New Zealand, where it is listed as Threatened and Nationally Vulnerable. For the first time in New Zealand, we report on the parasitic helminths infecting three individuals from Lake Wanaka, Otago, using morphological and molecular tools. Seven helminth species were found in the gastrointestinal tract: 2 nematodes (Contracaecum ovale and Baruscapillaria kamanae n.

DISTRIBUTION AND DIVERSITY OF DIPLOSTOMIDS IN NEW ZEALAND.

Parasitism is one of the most common consumer strategies and contributes a large portion to biological diversity. Trematodes in the family Diplostomidae are common in freshwater ecosystems worldwide, often residing in the eyes or brain of fish and then infecting fish-eating birds as adults. As a result, some species have broad geographic distributions due to the bird host's motility.

The people science: can passively crowdsourced internet data shed light on host-parasite interactions?

Every internet search query made out of curiosity by anyone who observed something in nature, as well as every photo uploaded to the internet, constitutes a data point of potential use to scientists. Researchers have now begun to exploit the vast online data accumulated through passive crowdsourcing for studies in ecology and epidemiology. Here, we demonstrate the usefulness of iParasitology, i.

Diomedenema dinarctos n. sp. (Spiruromorpha: Desmidocercidae), a new species of lung nematode in Fiordland crested penguins (Eudyptes pachyrhynchus; Sphenisciformes), from South Island, New Zealand.

Fiordland crested penguins Eudyptes pachyrhynchus Gray are thick-billed, crested penguins endemic to New Zealand that breed in small colonies in inaccessible places. They are assessed as Vulnerable by the IUCN. This is the first report of helminth parasites from this penguin species.

Gastrointestinal helminths of little blue penguins, Eudyptula novaehollandiae (Stephens), from Otago, New Zealand.

Data regarding helminth communities can provide insights into health, feeding interactions, behaviour and evolution of their host organisms. Penguins (Spheniscidae) are important components of marine food webs and tracking their helminth communities can be indicative of ecosystem health. New Zealand is home to 5 of the world's 19 penguin species and little is known about their gastrointestinal helminths.

Morphological and molecular characterisation of a new genus and species of acanthocephalan, Tenuisoma tarapungi n. g., n. sp. (Acanthocephala: Polymorphidae) infecting red-billed gulls in New Zealand, with a key to the genera of the Polymorphidae Meyer, 1931.

Acanthocephalans of the family Polymorphidae Meyer, 1931 are cosmopolitan parasites that infect the intestines of fish-eating birds and mammals. Polymorphid acanthocephalans recovered from the intestines of red-billed gulls (Chroicocephalus scopulinus (Forster)) from the Otago coast, New Zealand, although morphologically similar to the genus Arhythmorhynchus Lühe, 1911 nevertheless have a unique molecular profile showing considerable genetic differentation, and are here diagnosed and described as Tenuisoma tarapungi n. g.

Parasitological research in the molecular age.

New technological methods, such as rapidly developing molecular approaches, often provide new tools for scientific advances. However, these new tools are often not utilized equally across different research areas, possibly leading to disparities in progress between these areas. Here, we use empirical evidence from the scientific literature to test for potential discrepancies in the use of genetic tools to study parasitic vs non-parasitic organisms across three distinguishable molecular periods, the allozyme, nucleotide and genomics periods.

Revealing trophic transmission pathways of marine tapeworms.

Parasites are important components of natural systems, and among their various roles, parasites strongly influence the flow of energy between and within food webs. Over 1000 tapeworm species are known to parasitise elasmobranchs, although full life cycles are resolved for fewer than 10 of them. The lack in resolution stems from the inability to distinguish larval from adult stages using morphology alone.

Morphology and molecules resolve the identity and life cycle of an eye trematode, Philophthalmus attenuatus n. sp. (Trematoda: Philophthalmidae) infecting gulls in New Zealand.

Trematodes of the genus Philophthalmus are cosmopolitan parasites that infect the eyes of birds and mammals. They have the potential to affect the survival of their hosts and a few cases of human philophthalmiasis have occurred worldwide. Adults of known Philophthalmus species have never been recorded from bird hosts in New Zealand, despite their cercarial stage being a focus of various studies.