Katie O'Dwyer

Atlantic Technological University | ATU · Marine and Freshwater Research Centre

Trematodes and their snail hosts have developed intimate parasite-host associations, with snails supporting a diverse and often species-specific trematode fauna. In the faucet snail, Bithynia tentaculata (Caenogastropoda, Littorinimorpha), a unique trematode fauna has been recorded recently. However, knowledge of the exact species identity, phyloge...

Parasites represent a ubiquitous threat for most organisms, requiring potential hosts to invest in a range of strategies to defend against infection—these include both behavioural and physiological mechanisms. Avoidance is an essential first line of defence, but this behaviour may show a trade-off with host investment in physiological immunity. Imp...

Sustainable management of crustacean populations requires an understanding of the range of factors affecting different crustacean species. Recently, a high prevalence of a paramyxid parasite, Paramarteilia canceri , was reported in velvet crabs Necora puber in Ireland. Similar parasites have been known to cause mass mortalities in bivalves and, as...

Documenting temporal and spatial occurrence trends of Non-Indigenous Species (NIS) is essential to understand vectors and pathways of introduction, and for horizon scanning for future introductions. This study provides an overview of marine NIS found in the Republic of Ireland up to 2020. Taxonomic groups, species origin, and location of first repo...

Most bopyrid isopod parasites, which are crustaceans themselves, settle in the branchial chamber of decapod crustaceans and feed on host haemolymph. Here we report the results of an experiment on the common prawn Palaemon serratus and the parasite Bopyrus squillarum . Infected and uninfected prawns were stimulated with pokes of a plastic rod until...

Terns are a highly migratory group of seabirds that are found worldwide. In Ireland, there are five species of commonly breeding tern: Little Tern Sternula albifrons, Roseate Tern Sterna dougallii, Arctic Tern S. paradisaea, Common Tern S. hirundo and Sandwich Tern S. sandvicensis. Prior work has demonstrated that whilst many Irish tern species, in...

Glucocorticoid hormones (GCs) help vertebrates maintain homeostasis during and following challenging events. Short-term elevations in GC levels are necessary for survival, whereas longer-term changes can lead to reduced reproductive output and immunosuppression. Persistent environmental contaminants (ECs) are widespread globally. Experimental expos...

Parasites are important components of ecosystems, thus identifying patterns of their diversity is crucial for studies investigating ecosystem functioning, food web structure, trophic interactions and epidemiological parameters. Via an integrative taxonomic approach, we studied the diversity and distribution of trematodes of the genus Plagiorchis Lü...

The biodiversity of freshwater ecosystems globally still leaves much to be discovered, not least in the trematode parasite fauna they support. Echinostome trematode parasites have complex, multiple-host life-cycles, often involving migratory bird definitive hosts, thus leading to widespread distributions. Here, we examined the echinostome diversity...

Parasites and pathogens (hereafter parasites) commonly challenge organisms, but the extent to which their infections are physiologically stressful to hosts remains unclear. Importantly, vertebrate hormones, glucocorticoids (GCs), have been reported to increase, decrease or show no alterations stemming from infections, challenging the generality of...

Stable isotopes are widely used to identify trophic interactions and to determine trophic positions of organisms in food webs. Comparative studies have provided general insights into the variation in isotopic composition between consumers and their diet (discrimination factors) in predator‐prey and herbivore‐plant relationships while other major co...

Meta-analysis is the gold standard for synthesis in ecology and evolution. Together with estimating overall effect magnitudes, meta-analyses estimate differences between effect sizes via heterogeneity statistics. It is widely hypothesised that heterogeneity will be present in ecological/evolutionary meta-analyses due to the system-specific nature o...

The European sea squirt Ascidiella aspersa is a solitary tunicate native to the northeastern Atlantic, commonly found in shallow and sheltered marine ecosystems where it is capable of forming large clumps and outcompeting other invertebrate fauna at settlement. To date, there have been relatively few studies looking at the reproductive biology and...

We investigated for the first time the digenean parasites of Austrolittorina unifasciata Gray (Gastropoda: Littorinidae), a periwinkle snail inhabiting the rocky shores of Australia. Here we present detailed morphological descriptions and molecular data (sequences for the mitochondrial cox1 and the nuclear 28S rRNA gene) for the cercariae and intra...

Littorinid snails are one particular group of gastropods identified as important intermediate hosts for a wide range of digenean parasite species, at least throughout the Northern Hemisphere. However nothing is known of trematode species infecting these snails in the Southern Hemisphere. This study is the first attempt at cataloguing the digenean p...

For rocky shore gastropods, attachment strength is a key determinant of survival, as getting dislodged by wave action or predators has negative consequences. Yet little is known of the factors that cause inter-individual variation in attachment strength among conspecifics. Here, we test the influence of trematode infection on the suction-mediated a...

Sexual selection hypotheses stipulate that the Major Histocompatibility Complex genes (MHC) constitute a key molecular underpinning for mate choice in vertebrates. The last four decades saw growing empirical literature on the role of MHC diversity and dissimilarity in mate choice for a wide range of vertebrate animals, but with mixed support for it...

Statistical correlations of biodiversity patterns across multiple trophic levels have received considerable attention in various types of interacting assemblages, forging a universal understanding of patterns and processes in free-living communities. Host–parasite interactions present an ideal model system for studying congruence of species richnes...

The distribution of organisms at small spatial scales and their use of microhabitats are important determinants of species-level interactions. In many ubiquitous rocky shore invertebrates, use of intertidal microhabitats has previously been studied with relation to thermal and desiccation stress, ontogenetic changes and predation. Here, the effects...

Phenotypic diversification among colony members often leads to formation of physical castes which are morphologically specialised for particular tasks within the colony. The relative abundance of these castes and their body sizes represent two key aspects of the demography of a colony that may reflect the colony’s needs and conditions, and ultimate...

Although a small set of external factors account for much of the spatial variation in plant and animal diversity, the search continues for general drivers of variation in parasite species richness among host species. Qualitative reviews of existing evidence suggest idiosyncrasies and inconsistent predictive power for all proposed determinants of pa...