Climate Change and Shell-Boring Polychaetes (Annelida: Spionidae): Current State of Knowledge and the Need for More Experimental Research.

AbstractAnthropogenic climate change is considered to be one of the greatest threats facing marine biodiversity. The vast majority of experimental work investigating the effects of climate change stressors on marine organisms has focused on calcifying organisms, such as corals and molluscs, where cross-generational phenotypic changes can be easily quantified. Bivalves in particular have been the subject of numerous climate change studies, in part because of their economic value in the aquaculture industry and their important roles as ecosystem engineers. However, there has been little to no work investigating the effects of these stressors on the symbionts associated with these bivalves, specifically, their shell-boring polychaete parasites. This is important to understand because climate change may shift the synergistic relationship between parasite and host based on the individual responses of each. If such a shift favors proliferation of the polychaete, it may very well facilitate extinction of host bivalve populations. In this review I will (i) provide an overview of research completed thus far on the effects of climate change stressors on shell-boring polychaetes, (ii) discuss the technical challenges of studying these parasites in the laboratory, and (iii) propose a standardized framework for carrying out future in vitro and in vivo climate change experiments on shell-boring polychaetes.

Genetic Characterization of the Giant Liver Fluke, Fascioloides magna (Platyhelminthes: Fasciolidae) From the Adirondack Region of Northern New York.

PURPOSE: The giant liver fluke, Fascioloides magna, is an important parasite of white-tailed deer (Odocoileus virginanus), a commercially important game species in the northeastern United States. However, the parasite has never been genetically characterized from this region and so its genetic interrelationships with other enzootic populations on the continent are unknown. The purpose of this study was to genetically characterize F. magna from the Adirondack region of northern New York (NNY) and determine its relationship with its enzootic cohorts. METHODS: Flukes were extracted from seven livers of O. virginanus at three localities in and around the Adirondack Park in northern New York. DNA was extracted from eight individuals using standard procedures, and a 440-bp fragment of the COI gene was amplified using species-specific primers. F. magna sequences generated from a previous phylogeographic study were obtained from the GenBank database and a mtDNA dataset was compiled, aligned, and edited for molecular analyses. Analyses based on eight mtDNA sequences included haplotype network reconstruction, along with hierarchical and pairwise (ФST) AMOVA tests. RESULTS: F. magna from the Adirondacks was found to be most genetically similar to specimens from Minnesota based on shared haplotypes and relatively low genetic differentiation (ФST = 0.331). East coast enzootic populations exhibited panmixia while their west coast cohorts were genetically distinct. CONCLUSION: Based on the strong genetic similarities between F. magna from northern New York and Minnesota, we propose that the GLR enzootic range of F. magna be extended to encompass the Adirondack region of NNY.

Global connectivity patterns of the notoriously invasive mussel, Mytilus galloprovincialis Lmk using archived CO1 sequence data.

OBJECTIVE: The invasive mussel, Mytilus galloprovincialis has established invasive populations across the globe and in some regions, have completely displaced native mussels through competitive exclusion. The objective of this study was to elucidate global connectivity patterns of M. galloprovincialis strictly using archived cytochrome c oxidase 1 sequence data obtained from public databases. Through exhaustive mining and the development of a systematic workflow, we compiled the most comprehensive global CO1 dataset for M. galloprovincialis thus far, consisting of 209 sequences representing 14 populations. Haplotype networks were constructed and genetic differentiation was assessed using pairwise analysis of molecular variance. RESULTS: There was significant genetic structuring across populations with significant geographic patterning of haplotypes. In particular, South Korea, South China, Turkey and Australasia appear to be the most genetically isolated populations. However, we were unable to recover a northern and southern hemisphere grouping for M. galloprovincialis as was found in previous studies. These results suggest a complex dispersal pattern for M. galloprovincialis driven by several contributors including both natural and anthropogenic dispersal mechanisms along with the possibility of potential hybridization and ancient vicariance events.

A Student-Centered Framework for Teaching Undergraduate Parasitology.

Many biology subdisciplines are re-evaluating their undergraduate curriculum amid changing student attitudes towards education. However, a modern framework for undergraduate parasitology has yet to be formally outlined. We present a student-centered approach to teaching parasitology, which diminishes the power of the lectern and emphasizes the use of active learning techniques.

Repurposing of archived CO1 sequence data reveals unusually high genetic structure between North American and European zebra mussels (Dreissena polymorpha).

The invasion of the zebra mussel, Dreissena polymorpha in the Great Lakes of North America is regarded as one of the most catastrophic ecological events in recent history. Previous studies showed a close kinship between European zebra mussels and their invasive cohorts in the Great Lakes. In this study, we repurposed and reanalyzed archived CO1 sequence data from Lake Superior and multiple sites in Europe that were collected between 1991 and 2011 to illustrate an interesting pattern of genetic isolation that was overlooked in previous studies. The results showed extreme genetic isolation of Lake Superior zebra mussels as evident by high ϕST values and strong geographic patterning of Lake Superior haplotypes.

Predicting the Dispersal Potential of an Invasive Polychaete Pest along a Complex Coastal Biome.

Boccardia proboscidea is a recently introduced polychaete in South Africa where it is a notorious pest of commercially reared abalone. Populations were originally restricted to abalone farms but a recent exodus into the wild at some localities has raised conservation concerns due to the species' invasive status in other parts of the world. Here, we assessed the dispersal potential of B. proboscidea by using a population genetic and oceanographic modeling approach. Since the worm is in its incipient stages of a potential invasion, we used the closely related Polydora hoplura as a proxy due its similar reproductive strategy and its status as a pest of commercially reared oysters in the country. Populations of P. hoplura were sampled from seven different localities and a section of the mtDNA gene, Cyt b and the intron ATPSa was amplified. A high resolution model of the coastal waters around southern Africa was constructed using the Regional Ocean Modeling System. Larvae were represented by passive drifters that were deployed at specific points along the coast and dispersal was quantified after a 12-month integration period. Our results showed discordance between the genetic and modeling data. There was low genetic structure (Φ = 0.04 for both markers) and no geographic patterning of mtDNA and nDNA haplotypes. However, the dispersal model found limited connectivity around Cape Point-a major phylogeographic barrier on the southern African coast. This discordance was attributed to anthropogenic movement of larvae and adult worms due to vectors such as aquaculture and shipping. As such, we hypothesized that cryptic dispersal could be overestimating genetic connectivity. Though wild populations of B. proboscidea could become isolated due to the Cape Point barrier, anthropogenic movement may play the critical role in facilitating the dispersal and spread of this species on the southern African coast.