April M H Blakeslee

East Carolina University | ECU · Department of Biology

Estuarine organisms can evade biotic threats by utilizing low salinity extremes as refuge from natural enemies; however, they must also withstand osmotic stress. We investigated the spatiotemporal distribution of a mud crab host ( Rhithropanopeus harrisii ), and two castrating endoparasites (rhizocephalan Loxothylacus panopaei and entoniscid isopod...

Researchers often use surrogate species for assessing biodiversity—organisms that can indicate the presence of additional taxa or provide insight into environmental processes. As indicators of anthropogenic impact, “cross‐taxon” surrogates are theorized to be effective shortcuts for determining how communities respond to environmental change. Howev...

Along the U.S. east coast, the widespread non-native red alga Gracilaria vermiculophylla provides habitat for an array of macroinvertebrates, including the eastern mudsnail Ilyanassa obsoleta. Though I. obsoleta tolerates a wide temperature range, increases in summer water temperatures may enhance mortality; furthermore, the presence of non-native...

The Working Group on Ballast and Other Ship Vectors under the International Council for the Exploration of the Sea, Intergovernmental Oceanographic Commission of UNESCO, and Inter-national Maritime Organization (ICES/IOC/IMO WGBOSV) aims to provide scientific support to international decision-making to reduce the risk of spread and establishment of...

Stomach morphology can provide insights into an organism's diet. Gut size or length is typically inversely related to diet quality in most taxa, and has been used to assess diet quality in a variety of systems. However, it requires animal sacrifice and time‐consuming dissections. Measures of external morphology associated with diet may be a simpler...

Organisms vary in the timing of energy acquisition and use for reproduction. Thus, breeding strategies exist on a continuum, from capital breeding to income breeding. Capital breeders acquire and store energy for breeding before the start of the reproductive season, while income breeders finance reproduction using energy acquired during the reprodu...

Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and possibly even control, species interactions like host–parasite relationships. Yet, while studies have investigated host–parasites and microbiomes separately, little has been done to...

Understanding the factors that have shaped the current distributions and diversity of species is a central and longstanding aim of evolutionary biology. The recent inclusion of genomic data into phylogeographic studies has dramatically improved our understanding in organisms where evolutionary relationships have been challenging to infer. We used w...

Regeneration of lost appendages is a gradual process in many species, spreading energetic costs of regeneration through time. Energy allocated to the regeneration of lost appendages cannot be used for other purposes and, therefore, commonly elicits energetic trade-offs in biological processes. We used limb loss in the Asian shore crab Hemigrapsus s...

Foundation species like the eastern oyster (Crassostrea virginica) create complex habitats for organisms across multiple trophic levels. Historic declines in oyster abundance have prompted decades of restoration efforts. However, it remains unclear how long it takes for restored reefs to resemble the trophic complexity of natural reefs. We used a s...

Although intertidal crabs from the western Atlantic coast are relatively well studied for some parasite fauna, their parasitic isopods are poorly known. We document two endoparasitic entoniscids (Cancrion carolinusPearse & Walker, 1939 and Cryptocancrion brevibrachiumn. gen., n. sp.) from mud (Brachyura: Panopeidae) and stone (Brachyura: Menippidae...

Invasive species alter invaded ecosystems via direct impacts such as consumption. In turn, an invasive species’ ability to thrive in new habitats depends on its ability to exploit available resources, which may change over time and space. Diet quality and quantity are indicators of a consumer’s consumptive effects and can be strongly influenced by...

Renicolids digeneans parasitise aquatic birds. Their intramolluscan stages develop in marine and brackish-water gastropods, while metacercariae develop in molluscs and fishes. The systematics of renicolids is poorly developed, their life cycles are mostly unknown, and the statuses of many species require revision. Here, we establish based on integr...

Nonlethal injury is a pervasive stress on individual animals that can affect large portions of a population at any given time. Yet most studies examine snapshots of injury at a single place and time, making the implicit assumption that the impacts of nonlethal injury are constant. We sampled Asian shore crabs Hemigrapsus sanguineus throughout their...

The goal of the ICES Working Group on the Introduction and Transfers of Marine Organisms (WGITMO) is to contribute to the ICES vision and mission by addressing specific science objectives related to the introduction, spread and impacts of non-indigenous marine species (NIS). The expert working group provides information and advice on the impacts of...

Biological invasions influence species interactions around the globe, including host and parasite communities. We evaluated trematode parasite diversity and the potential for host-switching of parasites in 3 co-occurring crabs in the Northeast USA, including 1 native species (Cancer irroratus) and 2 non-natives (Carcinus maenas , Hemigrapsus sangui...

Due to anthropogenic mechanisms, global freshwater biodiversity is declining, and non‐indigenous species are consistently cited as a major threat to native ecosystems. In particular, exotic freshwater gastropods and their parasites have invaded ecosystems through deliberate introductions and/or accidental transfer. In many cases, introduced hosts e...

Novel facultative mutualisms that develop between native and non-native ecosystem engineers can lead to the retention of the non-native partner. In some cases, behavior plays an additional, but less understood, role in the development and persistence of mutualisms. In soft-sediment marine habitats along the western Atlantic, the native decorator wo...

Bacterial pathogens are a long-standing threat to the longevity and survival of crustacean hosts. Their presence and continuing emergence require close monitoring to understand their impact on fished, cultured, and wild crustacean populations. We report the presence of a new bacterial pathogen belonging to the Anaplasmataceae (Alphaproteobacteria:...

This study provides a broad phylogenetic analysis for the Eubrachyura, with the inclusion of three new Panopeidae mitochondrial genomes: Eurypanopeus depressus (flatback mud crab) (15,854bp), Panopeus herbstii (Atlantic mud crab) (15,812bp) and Rhithropanopeus harrisii (Harris, or ‘white-fingered’ mud crab) (15,892bp). These new mitogenomes were an...

Phylogeography provides insights into how historical and contemporary processes influence the genetic structure and gene flow in marine organisms around the globe. In benthic marine invertebrates, a species’ reproductive strategy can strongly impact phylogeographic patterns and distribution, with some direct-developing (non-planktonic) dispersers d...

In dynamic systems, organisms are faced with variable selective forces that may impose trade-offs. In estuaries, salinity is a strong driver of organismal diversity, while parasites shape species distributions and demography. We tested for trade-offs between low-salinity stress and parasitism in an invasive castrating parasite and its mud crab host...

By shuffling biogeographic distributions, biological invasions can both disrupt long‐standing associations between hosts and parasites and establish new ones. This creates natural experiments with which to study the ecology and evolution of host‐parasite interactions. In estuaries of the Gulf of Mexico, the white‐fingered mud crab (Rhithropanopeus...

Parasites can greatly affect the behavior of their hosts, influencing how they respond to biotic and abiotic factors within their communities. Some parasites are particularly impactful, causing significant reproductive and behavioral changes in hosts relative to uninfected conspecifics. In eastern North America, a non-native parasitic barnacle, Lox...

Ecological monitoring studies have shown that surrogate species can provide good predictive power for the community diversity of other taxa. In our study, we sampled for resident and transient fauna in several newly created oyster reefs. We also sampled for common multi-host parasites in these organisms, as parasite abundance can act as a surrogate...

Aim Genetic structure has proven difficult to predict for marine and estuarine species with multi‐day pelagic larval durations, since many disperse far less than expected based on passive transport models. In such cases, the gap between potential and realized dispersal may result from larval behaviours that evolved to facilitate retention and settl...

The illegal import of wildlife and wildlife products is a growing concern, and the U.S. is one of the world’s leading countries in the consumption and transit of illegal wildlife and their derivatives. Yet, few U.S. studies have analyzed the illegal wildlife trade (IWT) on a national or local scale. Moreover, to our knowledge, no studies have speci...

One of the most thoroughly studied marine snails in the world is the North Atlantic periwinkle Littorina littorea. In 2013, Buckland-Nicks et al. reported upon an “extensive community of organisms” living “inside” L. littorea in Nova Scotia, Canada. Conflicting with this report is a vast body of research on this snail since the mid-nineteenth centu...

Invasion dynamics are influenced by both vector operation and propagule pressure. Which propagules are entrained in a vector depends on how, where, and when a vector operates, but the timing and effects of vector operations on species delivery patterns is poorly resolved. Using the live marine baitworm trade, we tested vector selectivity across 3 b...

Species distributions are rapidly changing, facilitated by enhanced human migration and globalization over the past several centuries. Increasingly, species are becoming introduced to and established in novel locations that are often well outside their limits for natural dispersal. In marine systems, the anthropogenic transfer of living organisms h...

Symplegma is a genus of compound ascidians (Fam. Styelidae) with warm water affinities and distribution in tropical and subtropical waters of the Pacific, Indian and Atlantic Oceans. The first record of this genus (as S. viride) in the Mediterranean was from 1951 in the Levantine Sea, presumably entering the basin from the Red Sea through the Suez...

A single-stranded DNA (ssDNA) virus is presented from a metagenomic data set derived from Alphaproteobacteria-infected hepatopancreatic tissues of the crab Eurypanopeus depressus. The circular virus genome (4,768 bp) encodes 14 hypothetical proteins, some similar to other bacteriophages (Microviridae). Based on its relatedness to other Microviridae...

Species colonizations (both natural and anthropogenic) can be associated with genetic founder effects, where founding populations demonstrate significant genetic bottlenecks compared to native populations. Yet, many successfully established free-living species exhibit little reduction in genetic diversity-possibly due to multiple founding events an...

Parasitism can represent a potent agent of selection, and introduced parasites have the potential to substantially alter their new hosts' ecology and evolution. While significant impacts have been reported for parasites that switch to new host species, the effects of macroparasite introduction into naïve populations of host species with which they...

The Working Group on the Introductions and Transfers of Marine Organisms (WGITMO) has contributed several major achievements to the ICES vision, including the first ICES Viewpoint on Biofouling and its source document, two Cooperative Research Reports, and numerous pub-lications related to ToRs, and the continued population of the AquaNIS database....

Studies in ecological and community genetics have advanced our understanding of the role of intraspecific diversity in structuring communities and ecosystems. However, in near‐shore marine communities, these studies have mostly been restricted to seagrasses, marsh plants, and oysters. Yet, macroalgae are critically important ecosystem engineers in...

Invasive species can introduce parasites to, and/or acquire new parasites from, novel regions, thereby greatly influencing community interactions, including symbiotic relationships involving parasites. Host-switching of native and non-native parasites could enhance or dilute parasite transmission and spread among hosts. We investigated the effect o...

Many species of fish produce larvae that undergo a prolonged dispersal phase. However, evidence from a number of recent studies on demersal fishes suggests that the dispersal of propagules may not be strongly correlated with gene flow. Instead, other factors like larval behavior and the availability of preferred settlement habitat may be more impor...

Sequence data Sequence data for North Carolina Populations, Atlantic and Gulf of Mexico Populations (Mila et al., 2017), and German Populations (Van Tassell et al., 2015) of G. bosc

Haplotype data and sequence information In the table below, the first column represents the haplotype number (the actual sequence information for each haplotype follows this table). Columns 2–10 represent newly collected raw data from populations in North Carolina. These include the abundance of a particular haplotype per site. Columns 11–12 repres...

Regressions with salinity

Two genetically distinct lineages of European green crabs (Carcinus maenas) were independently introduced to eastern North America, the first in the early 19th century and the second in the late 20th century. These lineages first came into secondary contact in southeastern Nova Scotia, Canada (NS), where they hybridized, producing latitudinal genet...

Shoreline development can alter natural habitats, create novel habitats, and affect coastal community structure. Our study compares abundances and tidal variation patterns of palaemonid shrimps in artificial and natural estuarine habitats of Long Island, NY, USA. We sampled shrimps at three habitat types: floating docks, bulkheads, and natural shor...

Numerous marine species have been introduced via anthropogenic vectors; however, many species, including highly abundant ones, have uncertain invasion histories. Here, we include the first large-scale population genetics study of the Asian shorecrab (Hemigrapsus sanguineus) in native (east Asia) and non-native (east USA) regions to help resolve que...

Numerous non-indigenous species (NIS) have successfully established in new locales, where they can have large impacts on community and ecosystem structure. A loss of natural enemies, such as parasites, is one mechanism proposed to contribute to that success. While several studies have shown NIS are initially less parasitized than native conspecific...

Interactions between anthropogenic disturbances and introduced and native species can shift ecological communities, potentially leading to the successful establishment of additional invaders. Since its discovery in New Jersey in 1988, the Asian shore crab (Hemigrapsus sanguineus) has continued to expand its range, invading estuarine and coastal hab...

Parasites can impart heavy fitness costs on their hosts. Thus, understanding the spatial and temporal consistency in parasite pressure can elucidate the likeliness of parasites’ role as agents of directional selection, as well as revealing variable environmental factors associated with infection risk. We examined spatiotemporal variation in digenet...

Polychaete worms are hosts to a wide range of marine parasites; yet, studies on trematodes using these ecologically important species as intermediate hosts are lacking. During examination of the spionid polychaete Marenzelleria viridis collected on the north shore of Long Island, New York, putative trematode cysts were discovered in the body cavity...

The global transfer of live bait creates a potent vector (mechanism) for invasion of marine species, including associated biota (“hitchhikers”) not intended for shipment. Unlike other vectors of non-native species transfer in coastal marine systems (e.g., ship ballast water), vector management strategies to reduce transport of associated biota with...

AimFor over 80 years, the Maine baitworm trade has shipped live polychaete worms and packing algae ‘wormweed’ to distributors world-wide, while also consistently transferring a wide diversity and abundance of hitchhiking organisms of all life stages to numerous recipient communities. Here, we investigate this potent, yet underestimated, invasion ve...

A common signature of marine invasions worldwide is a significant loss of parasites (= parasite escape) in non-native host populations, which may confer a release from some of the harmful effects of parasitism (e.g., castration, energy extraction, immune activation, behavioral manipulation) and possibly enhance the success of non-indigenous species...

Biological invasions offer unique opportunities to investigate evolutionary dynamics at the peripheries of expanding pop- ulations. Here, we examine genetic patterns associated with admixture between two distinct invasive lineages of the European green crab, Carcinus maenas L., independently introduced to the northwest Atlantic. Previous investigat...

Marine invasions have risen over time with enhanced globalization, and so has the introduction of non-native hosts and their parasites. An important and well-supported paradigm of invasion biology is the significant loss of parasites that hosts enjoy in introduced regions compared to native regions (i.e. parasite escape), yet less is known about th...