Hemigrapsus Sanguineus Research Articles

Phylogenetic relationships of Grapsoidea and insights into the higher phylogeny of Brachyuran

Decapoda is one of the most diverse crustacean orders, and has become an important research subject. However, the phylogenetic relationships among the main lineages of Decapoda remain uncertain, especially in the order Brachyura. Herein, we sequenced the whole mitochondrial genome of V. litterata and constructed a phylogenetic tree to understand its phylogenetic relationships with other species. The results showed that the mitochondrial genome of V. litterata was generally similar to mitogenomes of Metazoa reported in the literature, with a size of 16,247 bp, 37 genes, and a control region. Both AT-skew and GC-skew were negative, indicating more abundant Cs and Ts than Gs and As. The gene arrangement of V. litterata is identical to those of Eriocheir hepuensis, Cyclograpsus granulosus, Hemigrapsus sanguineus, Helicana wuana, and Helice tientsinensis but differs from the pancrustacean ground pattern and typical arrangement of Brachyuran crabs. Phylogenetic reconstruction showed that V. litterata belongs to the Varunidae.

Exploring larval phenology as predictor for range expansion in an invasive species

Predicting range expansion of invasive species is one of the key challenges in ecology. We modelled the phenological window for successful larval release and development (WLR) in order to predict poleward expansion of the invasive crab Hemigrapsus sanguineus along the Atlantic coast of North America and north Europe. WLR quantifies the number of opportunities (in days) when larval release leads to a successful completion of the larval phase; WLR depends on the effects of temperature on the duration of larval development and survival. Successful larval development is a necessary requirement for the establishment of self‐persistent local populations. WLR was computed from a mechanistic model, based on in situ temperature time series and a laboratory–calibrated curve predicting duration of larval development from temperature. As a validation step, we checked that model predictions of the time of larval settlement matched observations from the field for our local population (Helgoland, North Sea). We then applied our model to the North American shores because larvae from our European population showed, in the laboratory, similar responses to temperature to those of a North American population. WLR correctly predicted the northern distribution limit in North American shores, where the poleward expansion of H. sanguineus appear to have stalled (as of 2015). For north Europe, where H. sanguineus is a recent invader, WLR predicted ample room for poleward expansion towards NE England and S Norway. We also explored the importance of year‐to‐year variation in temperature for WLR and potential expansion: variations in WLR highlighted the role of heat waves as likely promoters of recruitment subsidising sink populations located at the distribution limits. Overall, phenological windows may be used as a part of a warning system enabling more targeted programs for monitoring.

Startle response of the invasive Asian shore crab under different environmental conditions

In recent years, researchers have recognized the importance of behavioral factors for invasive species success. There is evidence that an organism’s ability to quickly react to stimuli may be one behavioral factor leading to invasive success. In this study, we analyzed the startle response of the invasive Asian shore crab Hemigrapsus sanguineus (De Haan, 1835), which measured here as a binary response variable of either active or inactive behavior when the rock they were under was suddenly lifted up. The behavior of H. sanguineus was compared to other crab species in the area to determine how species-dependent their responses were. This response was compared across an intertidal gradient with variation in temperature, intertidal elevation, substrate, time of day, and male-to-female ratios to determine if these affected the crabs’ responses. We found that H. sanguineus was more responsive than other species, perhaps indicative of a generally high activity level for this species. Surprisingly, we found that their behavior was not affected by any environmental factors tested. The consistently active behavior of this crab could be one factor contributing to its high level of success as an invasive species.

Megalopae of the invasive crab Hemigrapsus sanguineus metamorphose in response to marine biofilms from different potential habitats

Habitat characteristics favoring settlement and metamorphosis of larvae can affect the distribution and abundance of benthic marine invertebrates. Less selective responses to habitat cues by settling larvae can lead to broader distributions of species and potentially successful introduction to new geographic locations. This study tested whether marine biofilms, which serve as habitat cues for many invertebrates, enhance settlement and metamorphosis (molting) of megalopae of the invasive Asian shore crab Hemigrapsus sanguineus. Biofilms were allowed to develop on plastic mesh netting deployed in coastal locations with abundant rocky substrate (adult habitat) and estuarine locations with few rocks. Molting rates of laboratory-reared megalopae maintained with biofilm-covered netting were determined. Controls consisted of mesh netting without field-derived biofilms and seawater without netting. Experiments were also conducted with megalopae of a native species of estuarine mud crab, Dyspanopeus sayi, for comparison of responses. Both species molted faster in response to field biofilms regardless of habitat of biofilm development, although the response to biofilms compared to netting without biofilms was stronger for H. sanguineus than D. sayi. The broad response of megalopae of both species to biofilms suggests that positive responses to biofilms and physical structure could be important for successful colonization of crab species in general.

Prey size selection in invasive (Hemigrapsus sanguineus and H. takanoi) compared with native (Carcinus maenas) marine crabs

AbstractIntroductions of predators can have strong effects on native ecosystems and knowledge of the prey size selection of invasive predators is pivotal to understand their impact on native prey and intraguild competitors. Here, we investigated the prey size selection of two invasive crabs (Hemigrapsus sanguineus and Hemigrapsus takanoi) recently invading European coasts and compared them with native shore crabs (Carcinus maenas) which are known to feed on similar prey species. In laboratory experiments, we offered different size classes of native blue mussels (Mytilus edulis) to different size classes of the crab species in an effort to identify the respective prey size preferences and potential overlap in prey size range of native and invasive crabs. In all three species, the preferred prey size increased with crab size reflecting general predator–prey size relationships. Prey size preference did not differ among the crab species, i.e. crabs showed similar mussel size preference in relation to carapace width. Given that additional morphological measurements showed that both of the invasive crab species have much larger claws relative to their body size compared with the native species, this finding was surprising and may relate to differential claw morphologies or structural strength. These results suggest that the invasive crabs exert predation pressure on the same size classes of native mussels as the native crabs, with potential effects on mussel population dynamics due to the high densities of the invaders. In addition, the overlap in prey size range is likely to result in resource competition between invasive and native crabs.

Physiological Effects of Limb Loss on the Asian Shore Crab, Hemigrapsus sanguineus

Invasive species pose a considerable threat to biodiversity and the functioning of the ecosystem. Hemigrapsus sanguineus (Asian Shore Crab) has outnumbered native crabs on the northeast coast of North America since shortly after its introduction in the late 1980s. Asian Shore Crabs occur in high densities along much of the Atlantic coast from Maine to North Carolina. Our research focused on the relationship between limb loss and energy use and storage in both male and female Asian Shore Crabs as a means of understanding their ability to reach high population densities. We sampled 154 crabs of both sexes from Odiorne Point State Park in Rye, NH. We then dissected the individual specimens and measured limb loss and the mass of the hepatopancreas (an energy storage organ) and gonads. Our findings reveal that limb loss has similarly limited impacts on male and female crabs in terms of both energy storage and reproductive effort. We conclude that despite a high frequency of injury, the energetics of Asian Shore Crabs were largely unaffected, and that this may be one reason why this species has been able to achieve sustained high densities throughout much of its invaded range.

Population Decline of the Invasive Asian Shore Crab (Hemigrapsus sanguineus) and Dynamics of Associated Intertidal Invertebrates on Cape Cod, Massachusetts

A few moderately long-term studies have documented population dynamics of the invasive Hemigrapsus sanguineus (Asian Shore Crab) and species with which it interacts. One such study on Cape Cod reported exponential growth of the Asian Shore Crab through 2012, concurrent with declines in 2 resident species, but recent data at nearby sites suggest considerable geographic variation in population dynamics, with modest recovery of resident crab populations. We monitored the Cape Cod population for an additional 5 years to determine whether population growth of the Asian Shore Crab had slowed and whether there was any change in population dynamics of Carcinus maenas (Green Crab), Littorina littorea (Common Periwinkle), or Mytilus edulis (Blue Mussel). Asian Shore Crab density declined by nearly 90% since 2012. There was no evidence of recovery by the Green Crab, but the Blue Mussel experienced a brief but substantial increase in density in 2015, when both crab species displayed >70% reductions in density from the previous year. The pattern of population dynamics of the Asian Shore Crab from 2003 to 2017 is consistent with boom–bust dynamics, but it remains unclear whether the population will equilibrate near its current density or undergo recurrent boom–bust cycles.

Phenotypic plasticity in gastropod shell remodeling

AbstractA laboratory experiment was conducted with the marine gastropodLittorina littoreafrom three different sites in Long Island Sound to test for inducible responses to the non‐native predatory crabHemigrapsus sanguineus. Individuals ofL. littoreadid not exhibit decreased shell growth in response to increased predation risk, which differs from the response seen in other species ofLittorina.However, snails did exhibit slower growth in response to reduced food availability, as seen in other gastropods. Surprisingly, snails from two sites exhibited differences between the crab‐exposed and reduced food‐availability treatments in how they remodeled the thickness of different microstructural layers of shell material in apical parts of the shell. Although individuals ofL. littoreadid not show the typical shell thickening response seen in other gastropods, they did show differences among populations in remodeling their shell. This underlies the importance of examining how the shell is constructed and remodeled in studies of inducible defenses in gastropods, as well as the importance of examining animals from multiple populations.

Analysis of potential distribution and impacts for two species of alien crabs in Northern Europe

The Asian shore crab (Hemigrapsus sanguineus) and the brush-clawed shore crab (H. takanoi) both originate from east Asia but have in recent years established viable populations throughout coastal European waters. The two species are highly competitive and can occur in very high densities. Both species have been linked to the decrease of otherwise abundant native species such as the European shore crab (Carcinus maenas) and the common periwinkle (Littorina littorea). As both crabs are relatively new in European coastal waters, little is known about the full distribution range that may be achieved by these crabs and the ecological impact that may follow with an invasion of coastal habitats. In this study we investigated the potential distribution of Hemigrapsus in coastal waters of Northern Europe and the potential impact on the native competitor C. maenas. To this end we collected crabs on the Swedish west coast and on Helgoland and used these for behavioural experiments. We also collected new observation records of both species in Sweden and used these occurrences for building ecological niche models. We report that the potential distribution range of both H. sanguineus and H. takanoi extends from western Sweden to eastern Ireland (east–west) and southern Norway to western France (north–south). We also found evidence that H. takanoi can establish viable populations in nutrient-rich inshore areas of the western and southern Baltic Sea and that competition by H. sanguineus is likely to affect abundances of C. maenas in the areas where these species co-occur.

Phylogeographic studies on two shore crab species from East Asia: similar but different stories.

The genetic structure of marine organisms in the East Asian region has long been a subject of interest. Two grapsid crab species, Hemigrapsus penicillatus (De Haan, 1835) and Hemigrapsus sanguineus (De Haan, 1835), are commonly found in the rocky intertidal zones around this region. They are known to spread via larval migration, which makes them an appropriate model species for observing the genetic structure of East Asian intertidal invertebrate animals. We investigated the genetic structure of the East Asian crabs H. penicillatus and H. sanguineus. We collected specimens of H. penicillatus from seven locations (42 individuals) and of H. sanguineus from ten locations (58 individuals) in Korea, Japan, and Taiwan. We investigated and compared the genetic diversity and structure of populations of these species using mitochondrial cytochrome oxidase subunit I (COI) sequences. Our results show that both species are genetically structured between South Korea and Japan, and that the Taiwan population forms a cluster that is separate from those of the other countries. Populations of H. penicillatus contain less genetic diversity than those of H. sanguineus. These results suggest that there is a genetic structure between the two species at present in East Asia.

Horizon scanning for alien predatory crabs: insights from South Africa

Due to the presence of few dominant predators on South African rocky shores, this coastline could be vulnerable to invasion by predatory crabs. This study applied horizon scanning to create an ordered watch list of alien crab species that could establish along this coastline under present-day and future temperature scenarios. This was done by: (i) identifying the species with both an invasion history and a possible pathway to South Africa; (ii) comparing the temperature ranges of the species’ native and introduced distributions to those of each of the four South African ecoregions; and (iii) ranking the species based on their potential ecological impacts. Of the 56 alien predatory crab species known worldwide, 28 species have pathways to South Africa. Incompatible temperature ranges excluded only two species from each ecoregion. Negative ecological impacts in their invaded ranges placed Japanese shore crab Hemigrapsus sanguineus, brush-clawed shore crab H. takanoi and Chinese mitten crab Eriocheir sinensis at the top of the watch list. This study highlights that many alien crab species have the potential to reach South Africa, with most likely to survive. This watch list should be used to support targeted monitoring and so facilitate early detection of these species, should they reach South Africa.

Changes in Population Demography and Reproductive Output of the Invasive Hemigrapsus sanguineus (Asian Shore Crab) in the Long Island Sound from 2005 to 2017

Cross-intertidal transects at a western Long Island Sound estuary site provided estimates of the density of the non-native Hemigrapsus sanguineus (Asian Shore Crab) from 1998 to 2017, and measurements of crab size (carapace width; CW) from 2005 to 2017. Since 2001, average intertidal density declined by ∼5% per year. This decline was driven by decreases in the density of larger crabs, with consequent reductions in average and maximum sizes of both males and females. The proportion of the largest crabs (>24 mm CW) dropped from 10.1% of the population in 2005 to 1.4% in 2017. Individual reproductive output scales with size; thus, I estimate the loss of the largest females to have reduced population reproductive output by half between 2005 and 2017. Also, the frequency of ovigerous females in the smallest reproductively mature classes (12–14 mm CW) increased. Though the density and average size of Asian Shore Crab have declined significantly, resident and native crab populations have still not recovered.

Invasion dynamics: interactions between the European Green Crab Carcinus maenas and the Asian Shore Crab Hemigrapsus sanguineus

As ecosystems are increasingly inhabited by multiple invasive species, interactions among exotic species have the potential to negatively impact native communities and habitats, often in counterintuitive ways. In rocky intertidal habitats along southern New England, the recently introduced Asian Shore Crab, Hemigrapsus sanguineus, has been implicated in the displacement of the more established invasive European Green Crab, Carcinus maenas. We coupled faunal sampling with two field experiments to examine whether H. sanguineus is also displacing C. maenas in the Gulf of Maine. First, we investigated natural recruitment of the two species across an elevation gradient, using cage exclusion units to manipulate predator access. Excluding H. sanguineus adults significantly increased the density of C. maenas recruits, but not conspecific recruit density. Next, to simulate the transition that occurred from pre-invasion to the establishment of H. sanguineus, we conducted a predator inclusion experiment manipulating the density of adult H. sanguineus to examine the effects on C. maenas and conspecific recruit densities. In contrast to the previous experiment, we found that the density of H. sanguineus included in cages negatively affected conspecific recruit density but had no effect on C. maenas recruit density. We hypothesize that juxtaposing results from the two experiments may be a consequence of the considerably greater abundance of C. maenas recruits relative to H. sanguineus recruits during the first experiment. Our work highlights the importance of considering the multitude of factors that influence competitive and intraguild predation interactions, including density-dependent effects, ontogeny and life history characteristics.

Seasonal lipid storage and dietary preferences of native European vs. invasive Asian shore crabs

The invasive Asian shore crab Hemigrapsus sanguineus and the native European green crab Carcinus maenas share intertidal habitats along European North Atlantic shores and may compete for food. We evaluated the energy-storing capacities of the 2 species and determined their dietary preferences by means of lipid analysis and fatty acid trophic marker indices. Specimens of both sexes and various sizes were sampled in the rocky intertidal of the island of Helgoland (North Sea) in April, June, August, and October 2015. Total lipids of the midgut glands were significantly higher in H. sanguineus than in C. maenas and followed a distinct seasonal cycle in both sexes (ca. 20−50% of dry mass, DM). The lower lipid contents of C. maenas (ca. 20% of DM) remained at a similar level throughout the seasons. The seasonal differences in the females of H. sanguineus may be due to higher reproductive output and, consequently, lipid turnover, but remain unexplained in males. Trophic indices for Bacillariophyceae, Chlorophyta, and especially Phaeophyceae were higher in H. sanguineus than in C. maenas, suggesting a higher degree of herbivory of the invader. In contrast, the Rhodophyta index was higher in C. maenas. Thus, competition for food between the 2 species will probably be low in habitats rich in macroalgae. The ability of H. sanguineus to utilize mainly energy-poor algae but accumulate high-energy reserves may be an advantage for successfully establishing persistent populations in new habitats.

Physiological and behavioral response of the Asian shore crab, Hemigrapsus sanguineus, to salinity: implications for estuarine distribution and invasion.

The invasive Asian shore crab, Hemigrapsus sanguineus, is ubiquitous in the rocky intertidal zone of the western North Atlantic. A likely contributor to this colonization is that H. sanguineus is able to handle a wide range of salinities, and is thus more likely to spread through a greater geographic area of estuaries. This study investigated the salinity effects on this animal by observing survival across a range of salinities, the maintenance of hemolymph osmolality under different salinities, and behavioral preference for and avoidance of salinities. H. sanguineus showed high survival across a broad range of salinities, had little change in hemolymph osmolality over a short-term salinity shock, and behaviorally distinguished between salinities when presented with a choice, under both acclimation salinities of 5 PSU or 35 PSU. Such results suggest H. sanguineus has a hardiness for the rapid changes in salinity that happen in the intertidal zone, yet is capable of physically moving to a more optimal salinity. This enhances their competitiveness as an invader, particularly surviving lower salinities that present challenges during high-precipitation events in rocky intertidal areas, and partially explains this species’ dominance in this habitat type.

Competitive and agonistic interactions between the invasive Asian shore crab and juvenile American lobster.

Invasive species can have profound ecological and evolutionary impacts on native fauna, particularly those from overlapping guilds. Intraguild predation and competition often occur simultaneously, and ontogenetic shifts in competitive strength can dictate the magnitude and direction of species interactions. The recent introduction of the Asian shore crab Hemigrapsus sanguineus to the Atlantic coast of North America has resulted in the potential for considerable intraguild interactions with juvenile American lobsters Homarus americanus, with which it now co-occupies rocky intertidal and shallow subtidal habitats. We present data from 5 yr of monthly (May-October) field sampling revealing a significant decline in lobster density as H.sanguineus density increased in the low intertidal. To investigate potential mechanisms behind this pattern, we conducted three mesocosm experiments designed to examine whether competitive interactions between H.americanus and H.sanguineus are size- or density-dependent. Larger early benthic phase lobsters (16-34mm CL) outcompeted H.sanguineus for both food and shelter resources. These lobsters fed faster and more in the presence of H.sanguineus, effectively defended shelter, were responsible for the majority of agonistic interactions, and, in multiple instances, killed and consumed H.sanguineus. Effects on sheltering and agonstic interactions by these lobsters were independent of H.sanguineus density; however, prior shelter residency increased lobster agonistic behavior towards crabs. In contrast, H.sanguineus outcompeted smaller, early benthic phase lobsters (7.2-11.2mm CL) for shelter, and these interactions were density dependent. Displacement of lobsters from shelter by crabs and cumulative agonistic interactions instigated by crabs towards lobsters scaled positively with H.sanguineus density. Given the similarity of the invasion documented here and others occurring globally, these experiments demonstrate the importance of considering how factors such as ontogeny, density-dependence, and primacy influence the outcomes of interactions between intraguild predators. Disentangling how these factors structure intraguild interactions between invasive and endemic species will both advance our fundamental understanding of community ecology and enhance efforts to conserve and manage natural resources.

Changes in Population Sizes ofHemigrapsus sanguineus(Asian Shore Crab) and Resident Crab Species in Southeastern New England (2010–2016)

The invasion of Hemigrapsus sanguineus (Asian Shore Crab) has been of concern in northeastern North America since the late 1980s. A relatively long-term record (1998–2011) of density estimates in southern New England showed displacement of resident crab species at 3 locations in Massachusetts and Rhode Island. In 2016, I visited the same locations to estimate current crab densities. The springtime Asian Shore Crab density decreased at a coastal location, but increased at an estuarine location to >300 crabs/m2. Resident crabs Carcinus maenas (European Green Crab) and Mud Crabs in the family Panopeidae increased in abundance at all 3 locations.

Invasive versus native brachyuran crabs in a European rocky intertidal: respiratory performance and energy expenditures

The invasive Asian shore crab Hemigrapsus sanguineus is now the second most abundant intertidal crab in the North Sea after the native European green crab Carcinus maenas. To compare their respiratory performance and energy expenditures, we measured standard respiration rates of both species from around the island of Helgoland, North Sea, Germany (54°11′N, 7°53′E) in 2015. Oxygen consumption was recorded in a flow-through setup between 5 and 20 °C. At lower temperatures, H. sanguineus had similar respiration rates as C. maenas, but approximately twofold higher rates at higher temperatures. Numerical models for the calculation of individual respiration rates were established and applied to the entire intertidal populations around Helgoland to compare the energy expenditures of both species. Abundance and biomass data recorded in August 2014 showed that H. sanguineus reached values as high as 21 and 59%, respectively, compared to those of C. maenas. Based on these data and the numerical respiration models, the energy expenditures of both populations were calculated for the whole year 2014. The H. sanguineus population reached, depending on the assumed diet of both species (complete herbivory versus complete carnivory), 86–135% of the expenditure value of C. maenas. As population densities of H. sanguineus are likely to increase in the North Sea, the energy expenditure of the invader and thus its impact on the energy flux in the intertidal habitat will further increase. Whether this will lead to an impact on the local intertidal community depends on species-specific dietary preferences and remains to be investigated.

The invasion risk of species associated with Japanese Tsunami Marine Debris in Pacific North America and Hawaii

Marine debris from the Great Tsunami of 2011 represents a unique transport vector for Japanese species to reach Pacific North America and Hawaii. Here we characterize the invasion risk of invertebrate species associated with tsunami debris using a screening-level risk assessment tool – the Canadian Marine Invasive Screening Tool (CMIST). Higher-risk invertebrate invaders were identified for each of five different ecoregions. Some of these are well-known global invaders, such as the mussel Mytilus galloprovincialis and the ascidian Didemnum vexillum which already have invasion histories in some of the assessed ecoregions, while others like the sea star Asterias amurensis and the shore crab Hemigrapsus sanguineus have yet to invade large portions of the assessed ecoregions but also are recognized global invaders. In general, the probability of invasion was lower for the Gulf of Alaska and Hawaii, in part due to lower climate matches and the availability of other invasion vectors.

A comprehensive phylogenetic analysis of Grapsoidea crabs (Decapoda: Brachyura) based on mitochondrial cytochrome oxidase subunit 1 (CO1) genes

The sequences of mitochondrial cytochrome c oxidase subunit I (CO1) genes of eight species crabs of Grapsoidea were determined and analyzed in this paper. The traditional classification is that Grapsidae contains four subfamilies comprising Grapsinae, Varuninae, Sesarminae, and Plagusiinae, which are also treated as families in some studies. There is a lack of clarity in the classification of some species, such as Eriocheir species. In this study, we conducted the first exploration of evolutionary relationships among species based on analysis of the molecular data of CO1 genes of eight species (Sesarmops sinensis, Clistocoeloma sinensis, Perisesarma bidens, Helice latimera, Helice tientsinensis, Helice wuana, Hemigrapsus sanguineus, and Varuna litterata). We provide a detailed and comprehensive view of the phylogenetic relationships of the Grapsoidea species determined by maximum likelihood and Bayesian inference analyses. The results show that S. sinensis, C. sinensis, and P. bidens are part of Sesarmidae, Grapsoidea, while H. latimera, H. tientsinensis, H. wuana, H. sanguineus, and V. litterata belong to Varunidae, Grapsoidea. The results revealed that Varunidae should be monophyletic and Sesarmidae should be paraphyletic.