Microorganisms are ubiquitous in the environment and provide genetic and physiological functions ... more Microorganisms are ubiquitous in the environment and provide genetic and physiological functions to multicellular organisms. Knowledge on the associated microbiota is becoming highly relevant to understand the host’s ecology and biology. Among invertebrates, many examples of endosymbiosis have been described, such as those in corals, ants, and termites. At present, however, little is known on the presence, diversity, and putative roles of the microbiota associated to brachyuran crabs in relation to their environment. In this work we investigated the associated microbiota of three populations of the terrestrial brachyuran crab Chiromantes haematocheir to find evidence of a conserved organ-specific microbiome unrelated to the population of origin and dissimilar from environmental microbial assemblages. Bacterial 16S rRNA gene and fungal ITS sequences were obtained from selected crab organs and environmental matrices to profile microbial communities. Despite the presence of truly marin...
Crustaceans are characterized by some of the most variable genome sizes among animals. Significan... more Crustaceans are characterized by some of the most variable genome sizes among animals. Significant relationships between genome size and specific eco-physiological and morphological features have been described in many crustacean taxa, such as Amphipoda, Ostracoda, Cladocera, and Copepoda. A consistent pattern of genome size variation is yet to be found, however, in one of the most specious order of crustaceans, the Decapoda. We investigated how genome size is related to selected eco-physiological and life-history traits in species belonging to this order. We analyzed the respiratory, excretory, and developmental adaptations of 179 decapod species inhabiting shallow marine, deep marine, freshwater, intertidal, and terrestrial habitats. Our results show that the genome size is significantly larger in decapods that have a direct development. Moreover, in Anomura, Astacidea, and Brachyura we found larger genome sizes in species (i) living in freshwater habitats, (ii) using gills as a s...
Brachyura is one of the most specious infra-order belonging to Decapoda and it plays a central ro... more Brachyura is one of the most specious infra-order belonging to Decapoda and it plays a central role from an ecological and economic point of view. Despite its importance, cytogenetic studies on Brachyura (Decapoda) are extremely limited due to the difficulties in obtaining chromosome preparations of good quality. Molecular cytogenetic have proven to provide basic knowledge on the genome organization of species and in methods for manipulating genomes. It is also very useful to support aquaculture. In this study we focused on six semi-terrestrial mangrove crab species to test several variations of technical steps to produce chromosome preparations in Brachyura. The best results were obtained using cells from early stage embryos incubated with 0.0005% nocodazole or 0.05% colchicine and hypotonized with 0.075 M KCl solution. The best method to analyze the chromosomes was the use of confocal microscope after DAPI staining. We recorded a high chromosome number for the six study species. S...
Background Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts ... more Background Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts across the world. They host a unique faunal community, dominated by brachyuran crabs and gastropods. These invertebrates strongly contribute to the functionality of the entire forest. The reliable assessment of mangrove faunal diversity is, thus, a crucial step for efficient management and conservation plans, but it is hindered by difficulties in species identification. Here we provide a verified DNA barcode library for brachyuran crabs and gastropods inhabiting the mangroves of the Greater Bay Area, Southern China. In particular, we collected and morphologically identified 1100 specimens of mangrove associated brachyuran crabs and gastropods. The partial sequences of the mtDNA cytochrome oxidase subunit I gene were obtained from 275 specimens. Barcode sequences were then used to delineate Molecular Operational Taxonomic Units (MOTUs), employing three different delimitation methods: the ...
Proceedings of the National Academy of Sciences, 2021
Significance Global mangrove deforestation and degradation drive the loss of the associated inver... more Significance Global mangrove deforestation and degradation drive the loss of the associated invertebrate fauna vital to ecosystem services. The functional diversity and resilience of this fauna has not been assessed. We show that even small mangrove patches host functionally diverse faunal assemblages and can act as biodiversity reservoirs. However, globally, functional redundancy of mangrove invertebrates (i.e., the average number of species performing a similar functional role in an assemblage) is extremely low, except in Southeast Asia. Thus, even a modest local loss of invertebrate diversity will have significant negative consequences for mangrove functionality and resilience. Current approaches to assess threats to mangroves heavily rely on loss in areal extent, but our results suggest that loss of function may be more vulnerable.
Background Studies on marine community dynamics and population structures are limited by the lack... more Background Studies on marine community dynamics and population structures are limited by the lack of exhaustive knowledge on the larval dispersal component of connectivity. Genetic data represents a powerful tool in understanding such processes in the marine realm. When dealing with dispersion and connectivity in marine ecosystems, many evidences show patterns of genetic structure that cannot be explained by any clear geographic trend and may show temporal instability. This scenario is usually referred to as chaotic genetic patchiness, whose driving mechanisms are recognized to be selection, temporal shifts in local population dynamics, sweepstakes reproductive success and collective dispersal. In this study we focused on the marbled crab Pachygrapsus marmoratus that inhabits the rocky shores of the Mediterranean Sea, Black Sea and East Atlantic Ocean, and disperses through planktonic larvae for about 1 month. P. marmoratus exhibits unexpectedly low connectivity levels at local scal...
The spatial distribution of mangrove crabs has been commonly associated with tree zonation and ab... more The spatial distribution of mangrove crabs has been commonly associated with tree zonation and abiotic factors such as ground temperature and soil granulometry. Conversely, no studies were designed to investigate the role of competition for resources and predation in shaping crab distribution in mangroves, despite these biotic factors are recognised as key determinants for spatial patterns observed in the communities colonising rocky and sandy intertidal habitats.We studied floral and faunal assemblages in two zones of a Sri Lankan mangrove, a man-made upper intertidal level and a natural eulittoral, mid-shore one. Leaf choice experiments were designed to study both feeding rate and intra and inter-specific interactions for food of sesarmid crabs in the two habitats in order to better understand crab spatial distribution. The two intertidal belts differed in terms of floral composition and crab species abundance. The eulittoral zone was strongly dominated by Neosarmatium smithi, whi...
The extent of genetic structure of a species is determined by the amount of current gene flow and... more The extent of genetic structure of a species is determined by the amount of current gene flow and the impact of historical and demographic factors. Most marine invertebrates have planktonic larvae and consequently wide potential dispersal, so that genetic uniformity should be common. However, phylogeographic investigations reveal that panmixia is rare in the marine realm. Phylogeographic patterns commonly coincide with geographic transitions acting as barriers to gene flow. In the Mediterranean Sea and adjoining areas, the best known barriers are the Atlantic-Mediterranean transition, the Siculo-Tunisian Strait and the boundary between Aegean and Black seas. Here, we perform the so far broadest phylogeographic analysis of the crab Pachygrapsus marmoratus, common across the north-eastern Atlantic Ocean, Mediterranean and Black seas. Previous studies revealed no or weak genetic structuring at meso-geographic scale based on mtDNA, while genetic heterogeneity at local scale was recorded...
The spatial distribution and the amount of intraspecific genetic variation of marine organisms ar... more The spatial distribution and the amount of intraspecific genetic variation of marine organisms are strongly influenced by many biotic and abiotic factors. Comparing biological and genetic data characterizing species living in the same habitat can help to elucidate the processes driving these variation patterns. Here, we present a comparative multispecies population genetic study on seven mangrove crabs co-occurring in the West Indian Ocean characterized by planktotrophic larvae with similar pelagic larval duration. Our main aim was to investigate whether a suite of biological, behavioural and ecological traits could affect genetic diversities of the study species in combination with historical demographic parameters. As possible current explanatory factors, we used the intertidal micro-habitat colonised by adult populations, various parameters of individual and population fecundity, and the timing of larval release. As the genetic marker, we used partial sequences of cytochrome oxid...
Mangroves are critically threatened by human activities, despite the important ecosystem function... more Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p'-DDE contamination, with concentrations higher than 3μgkg(-1) in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations.
Una delle maggiori cause del declino numerico dei Chirotteri a livello europeo è senza dubbio la ... more Una delle maggiori cause del declino numerico dei Chirotteri a livello europeo è senza dubbio la progressiva scomparsa dei loro rifugi, generalmente dovuta alla presenza dell’uomo. Alcune specie si sono tuttavia adattate ad utilizzare come riparo alcuni manufatti umani, anche durante alcune delle fasi più importanti del loro ciclo biologico. Le recenti tecniche costruttive, tuttavia, sono sempre più avare di spazi disponibili da poter colonizzare, mentre le vecchie abitazioni che vengono abbandonate dall’uomo e utilizzate dai pipistrelli finiscono per crollare. Anche le specie di Chirotteri più antropofile si trovano dunque a fronteggiare questa crisi dei rifugi. All’interno del Parco Naturale di Migliarino San Rossore Massaciuccoli è presente una delle colonie riproduttive di Rhinolophus ferrumequinum più grandi d’Italia, che utilizza come rifugio un rudere abbandonato che fino al 2006 era a serio rischio di crollo. Grazie al recente progetto LIFE NATURA “DUNETOSCA” è stato possibi...
Microorganisms are ubiquitous in the environment and provide genetic and physiological functions ... more Microorganisms are ubiquitous in the environment and provide genetic and physiological functions to multicellular organisms. Knowledge on the associated microbiota is becoming highly relevant to understand the host’s ecology and biology. Among invertebrates, many examples of endosymbiosis have been described, such as those in corals, ants, and termites. At present, however, little is known on the presence, diversity, and putative roles of the microbiota associated to brachyuran crabs in relation to their environment. In this work we investigated the associated microbiota of three populations of the terrestrial brachyuran crab Chiromantes haematocheir to find evidence of a conserved organ-specific microbiome unrelated to the population of origin and dissimilar from environmental microbial assemblages. Bacterial 16S rRNA gene and fungal ITS sequences were obtained from selected crab organs and environmental matrices to profile microbial communities. Despite the presence of truly marin...
Crustaceans are characterized by some of the most variable genome sizes among animals. Significan... more Crustaceans are characterized by some of the most variable genome sizes among animals. Significant relationships between genome size and specific eco-physiological and morphological features have been described in many crustacean taxa, such as Amphipoda, Ostracoda, Cladocera, and Copepoda. A consistent pattern of genome size variation is yet to be found, however, in one of the most specious order of crustaceans, the Decapoda. We investigated how genome size is related to selected eco-physiological and life-history traits in species belonging to this order. We analyzed the respiratory, excretory, and developmental adaptations of 179 decapod species inhabiting shallow marine, deep marine, freshwater, intertidal, and terrestrial habitats. Our results show that the genome size is significantly larger in decapods that have a direct development. Moreover, in Anomura, Astacidea, and Brachyura we found larger genome sizes in species (i) living in freshwater habitats, (ii) using gills as a s...
Brachyura is one of the most specious infra-order belonging to Decapoda and it plays a central ro... more Brachyura is one of the most specious infra-order belonging to Decapoda and it plays a central role from an ecological and economic point of view. Despite its importance, cytogenetic studies on Brachyura (Decapoda) are extremely limited due to the difficulties in obtaining chromosome preparations of good quality. Molecular cytogenetic have proven to provide basic knowledge on the genome organization of species and in methods for manipulating genomes. It is also very useful to support aquaculture. In this study we focused on six semi-terrestrial mangrove crab species to test several variations of technical steps to produce chromosome preparations in Brachyura. The best results were obtained using cells from early stage embryos incubated with 0.0005% nocodazole or 0.05% colchicine and hypotonized with 0.075 M KCl solution. The best method to analyze the chromosomes was the use of confocal microscope after DAPI staining. We recorded a high chromosome number for the six study species. S...
Background Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts ... more Background Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts across the world. They host a unique faunal community, dominated by brachyuran crabs and gastropods. These invertebrates strongly contribute to the functionality of the entire forest. The reliable assessment of mangrove faunal diversity is, thus, a crucial step for efficient management and conservation plans, but it is hindered by difficulties in species identification. Here we provide a verified DNA barcode library for brachyuran crabs and gastropods inhabiting the mangroves of the Greater Bay Area, Southern China. In particular, we collected and morphologically identified 1100 specimens of mangrove associated brachyuran crabs and gastropods. The partial sequences of the mtDNA cytochrome oxidase subunit I gene were obtained from 275 specimens. Barcode sequences were then used to delineate Molecular Operational Taxonomic Units (MOTUs), employing three different delimitation methods: the ...
Proceedings of the National Academy of Sciences, 2021
Significance Global mangrove deforestation and degradation drive the loss of the associated inver... more Significance Global mangrove deforestation and degradation drive the loss of the associated invertebrate fauna vital to ecosystem services. The functional diversity and resilience of this fauna has not been assessed. We show that even small mangrove patches host functionally diverse faunal assemblages and can act as biodiversity reservoirs. However, globally, functional redundancy of mangrove invertebrates (i.e., the average number of species performing a similar functional role in an assemblage) is extremely low, except in Southeast Asia. Thus, even a modest local loss of invertebrate diversity will have significant negative consequences for mangrove functionality and resilience. Current approaches to assess threats to mangroves heavily rely on loss in areal extent, but our results suggest that loss of function may be more vulnerable.
Background Studies on marine community dynamics and population structures are limited by the lack... more Background Studies on marine community dynamics and population structures are limited by the lack of exhaustive knowledge on the larval dispersal component of connectivity. Genetic data represents a powerful tool in understanding such processes in the marine realm. When dealing with dispersion and connectivity in marine ecosystems, many evidences show patterns of genetic structure that cannot be explained by any clear geographic trend and may show temporal instability. This scenario is usually referred to as chaotic genetic patchiness, whose driving mechanisms are recognized to be selection, temporal shifts in local population dynamics, sweepstakes reproductive success and collective dispersal. In this study we focused on the marbled crab Pachygrapsus marmoratus that inhabits the rocky shores of the Mediterranean Sea, Black Sea and East Atlantic Ocean, and disperses through planktonic larvae for about 1 month. P. marmoratus exhibits unexpectedly low connectivity levels at local scal...
The spatial distribution of mangrove crabs has been commonly associated with tree zonation and ab... more The spatial distribution of mangrove crabs has been commonly associated with tree zonation and abiotic factors such as ground temperature and soil granulometry. Conversely, no studies were designed to investigate the role of competition for resources and predation in shaping crab distribution in mangroves, despite these biotic factors are recognised as key determinants for spatial patterns observed in the communities colonising rocky and sandy intertidal habitats.We studied floral and faunal assemblages in two zones of a Sri Lankan mangrove, a man-made upper intertidal level and a natural eulittoral, mid-shore one. Leaf choice experiments were designed to study both feeding rate and intra and inter-specific interactions for food of sesarmid crabs in the two habitats in order to better understand crab spatial distribution. The two intertidal belts differed in terms of floral composition and crab species abundance. The eulittoral zone was strongly dominated by Neosarmatium smithi, whi...
The extent of genetic structure of a species is determined by the amount of current gene flow and... more The extent of genetic structure of a species is determined by the amount of current gene flow and the impact of historical and demographic factors. Most marine invertebrates have planktonic larvae and consequently wide potential dispersal, so that genetic uniformity should be common. However, phylogeographic investigations reveal that panmixia is rare in the marine realm. Phylogeographic patterns commonly coincide with geographic transitions acting as barriers to gene flow. In the Mediterranean Sea and adjoining areas, the best known barriers are the Atlantic-Mediterranean transition, the Siculo-Tunisian Strait and the boundary between Aegean and Black seas. Here, we perform the so far broadest phylogeographic analysis of the crab Pachygrapsus marmoratus, common across the north-eastern Atlantic Ocean, Mediterranean and Black seas. Previous studies revealed no or weak genetic structuring at meso-geographic scale based on mtDNA, while genetic heterogeneity at local scale was recorded...
The spatial distribution and the amount of intraspecific genetic variation of marine organisms ar... more The spatial distribution and the amount of intraspecific genetic variation of marine organisms are strongly influenced by many biotic and abiotic factors. Comparing biological and genetic data characterizing species living in the same habitat can help to elucidate the processes driving these variation patterns. Here, we present a comparative multispecies population genetic study on seven mangrove crabs co-occurring in the West Indian Ocean characterized by planktotrophic larvae with similar pelagic larval duration. Our main aim was to investigate whether a suite of biological, behavioural and ecological traits could affect genetic diversities of the study species in combination with historical demographic parameters. As possible current explanatory factors, we used the intertidal micro-habitat colonised by adult populations, various parameters of individual and population fecundity, and the timing of larval release. As the genetic marker, we used partial sequences of cytochrome oxid...
Mangroves are critically threatened by human activities, despite the important ecosystem function... more Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p'-DDE contamination, with concentrations higher than 3μgkg(-1) in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations.
Una delle maggiori cause del declino numerico dei Chirotteri a livello europeo è senza dubbio la ... more Una delle maggiori cause del declino numerico dei Chirotteri a livello europeo è senza dubbio la progressiva scomparsa dei loro rifugi, generalmente dovuta alla presenza dell’uomo. Alcune specie si sono tuttavia adattate ad utilizzare come riparo alcuni manufatti umani, anche durante alcune delle fasi più importanti del loro ciclo biologico. Le recenti tecniche costruttive, tuttavia, sono sempre più avare di spazi disponibili da poter colonizzare, mentre le vecchie abitazioni che vengono abbandonate dall’uomo e utilizzate dai pipistrelli finiscono per crollare. Anche le specie di Chirotteri più antropofile si trovano dunque a fronteggiare questa crisi dei rifugi. All’interno del Parco Naturale di Migliarino San Rossore Massaciuccoli è presente una delle colonie riproduttive di Rhinolophus ferrumequinum più grandi d’Italia, che utilizza come rifugio un rudere abbandonato che fino al 2006 era a serio rischio di crollo. Grazie al recente progetto LIFE NATURA “DUNETOSCA” è stato possibi...
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