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Understanding the legacy of stress and whether organisms can adapt or acclimate is an incredibly important question in our rapidly changing world. Organisms can adapt through genetic changes that are passed slowly from generation to generation and/or they can acclimate to a stress within a generation using plasticity (within-generational plasticity, WGP). Intermediate between the two responses is transgenerational plasticity (TGP), which occurs when a change in offspring phenotype or reaction norm is cued by an environmental signal in the parent (or previous generations) without involving a genetic change. Genetic adaptation, WGP, and TGP can all act and interact to create phenotypes in response to a given environmental regime. However, while comparisons among disparate studies and modeling approaches provide us with some predictions as to what forms of plasticity should be adaptive and the conditions under which these occur, there are few empirical data testing these predictions. My dissertation sought to empirically test the relative importance of TGP and other forms of plasticity among populations and species that vary in key traits and environmental characteristics. Marine invertebrates offer unique opportunities for progress because of their diversity of life history strategies, yet they are currently underrepresented in this growing body of literature. Overall, my approach was to run fully factorial experiments manipulating prior exposure either within a generation and/or across generations and measuring the relevant phenotypic responses. The first two chapters of my dissertation focused on linking predictive theory with empirical examples by examining how environmental variance and population history affect the use of plasticity across populations within a generation (Chapter 1) and across generations (Chapter 2). The third chapter took a more applied approach and attempted to understand the stress legacy effects within and across generations in order to optimize the fitness of a culturally and commercially important species in the face of climate change (Chapter 3).

Obrast je združba organizmov, ki obrašča podvodne strukture človeškega izvora in je ena od oblik morske epibentoške združbe trdnega dna. Njen razvoj skozi čas zaznamujeta sezonska in sukcesijska dinamika zaraščanja. Ena pomembnejših ekosistemskih storitev združbe obrasti je njena filtracijska učinkovitost (FU) in z njo povezano izboljšanje kvalitete morske vode. Namen raziskave je bil opisati časovno dinamiko obrasti v slovenskem priobalnem morju, eksperimentalno oceniti hitrosti precejanja (CR) za nekatere pogoste filtratorje v tej združbi in oceniti celotno FU obrasti na manjših podvodnih strukturah. Na lokaciji Morgan pri Piranu smo v mesečnih razmakih v obdobju enega leta postavili nosilce s ploščicami iz terakote in sprva mesečno ter nato redkeje združbo na ploščicah analizirali z laboratorijskimi in fotografskimi metodami. Poskuse za oceno CR smo izvedli z merjenjem upada števila hranljivih delcev v suspenziji pri hranjenju kozolnjakov vrste Styela plicata in mahovnjakov vrste Schizoporella errata ter Bugula neritina v kontroliranih laboratorijskih razmerah. FU združbe obrasti smo ocenili na biofiltrih, obraščenih valjih iz plastične mreže. Na naseljevanje pritrjenih nevretenčarjev je vplival čas postavitve struktur, pomembno vlogo pa je imela temperatura morja. Vrstno najbolj pestre in pogoste skupine nevretenčarjev so bili mahovnjaki (Bryozoa), črvi cevkarji (Serpulidae) in školjke (Bivalvia). Pokazali smo, da je S. errata, zaradi svoje abundance in visokih CR, pomemben filtrator v slovenskem priobalnem morju. Izračunali smo, da lahko obrasli biofiltri prefiltrirajo velike količine morske vode, podobne strukture pa bi lahko ob strateški namestitvi blažile probleme povezane z evtrofikacijo na obremenjenih delih slovenske obale. The fouling community is a community of organisms that cover underwater structures of anthropogenic origin, and is a form of marine hard bottom epibenthic community. Its temporal patterns are determined by its seasonal and successional dynamics. One of the most important ecosystem services provided by the fouling community is its filtration capacity (FE), which improves the quality of seawater. The aim of this research was to describe the temporal patterns of the fouling community in the Slovenian coastal sea, to estimate experimentally the clearance rates (CR) for some common filter feeders of this community and to estimate the overall FE of the fouling community on small underwater structures. At the Morgan locality near Piran, structures carrying terracotta plates were placed monthly over the course of a year, and the assemblage on the plates was analysed using laboratory and photographic methods, first monthly and then at less frequent intervals. Experiments to evaluate CR were conducted with the ascidian Styela plicata and two bryozoan species, Schizoporella errata and Bugula neritina, measuring the decrease in the number of particles in suspension when the animals were fed under controlled laboratory conditions. The FE of the fouling community was evaluated in the case of biofilters, overgrown cylinders made of plastic mesh. Colonization of sessile invertebrates was influenced by the timing of placement of the structures, with sea temperature playing an important role. The most diverse and abundant invertebrate groups were bryozoans (Bryozoa), tubeworms (Serpulidae), and bivalves (Bivalvia). We have shown, that, due to its abundance and high CR, S. errata is an important filter feeder in the Slovenian coastal sea. We have as well demonstrated that fouled biofilters filter large amounts of seawater and we anticipate that, if strategically placed, similar structures could alleviate problems associated with eutrophication in degraded areas of the Slovenian coast.

Cilj ovog diplomskog rada bio je odrediti profil masnih kiselina, udio ukupnih polifenola i antiradikalnu aktivnost morskih organizama Jadranskog mora, spužve Petrosia ficiformis (izronjena kod poluotoka Rtina kod Paškog mosta) i mahovnjaka Bugula neritina (izronjen u uvali Luka, Dugi otok). Za ekstrakciju lipida korištena je metoda po Folch-u, a za identifikaciju masnih kiselina korištena je plinska kromatografija s plamenoionizacijskim detektorom. Ukupni polifenoli su ekstrahirani primjenom ultrazvuka, te je određen udio polifenola spektrofotometrijski pomoću Folin-Ciocalteuovog reagensa. DPPH metodom je određena antiradikalna aktivnost. Na temelju dobivenih rezultata utvrđeno je da su u P. ficiformis najzastupljeniji cis- i trans- izomeri oleinske kiseline (25,34 ± 0,26 %), a u B. neritina dominira palmitinska kiselina (48,38 ± 0,44 %). Također je uočeno da P. ficiformis (72,19 μg GAE/mL) ima veći udio ukupnih polifenola, nego B. neritina (59,01 μg GAE/mL). Određivanjem antiradikalne aktivnosti ultrazvučnom ekstrakcijom, na 30 °C su dobivene najveće vrijednosti za P.ficiformis (93,57 ± 0,70 % DPPH) i za B.neritina (93,65 ± 0,51 % DPPH). Povećanjem temperature smanjivala se antiradikalna aktivnost za oba uzorka. The aim of this study was to determine the profile of fatty acids, total polyphenol content and antiradical activity in marine organisms from the Adriatic Sea Petrosia ficiformis and Bugula neritina. The sponge P. ficiformis was surfaced near the Rtina peninsula near the Paški bridge, and the bryozoa B. neritina was surfaced in the Luka cove, Dugi otok. The Folch method was used for the extraction of total lipids, and gas chromatography with flame-ionization detector was used for fatty acid identification. Total polyphenols were extracted using ultrasound, and polyphenol content was determined spectrophotometrically using the Folin- Ciocalteu reagent. The antiradical activity was determined by the DPPH method. Based on the obtained results, it was determined that cis- and trans- isomers of oleic acid (25.34 ± 0.26 %) are the most abundant in the sponge P. ficiformis, and palmitic acid (48.38 ± 0.44 %) dominates in bryozoan B. neritina. It was also observed that P. ficiformis (72.19 μg GAE/mL) has a higher content of total polyphenols than B. neritina (59.01 μg GAE/mL). By determining the antiradical activity by ultrasonic extraction, the highest values were obtained at 30 °C for P. ficiformis (93.57 ± 0.70 % DPPH) and for B. neritina (93.65 ± 0.51 % DPPH). Increasing the temperature decreased the antiradical activity for both samples.

Bugula neritina (Linnaeus, 1758) (Fig. 15) Sertularia neritina Linnaeus, 1758: 815. Bugula neritina: Lichtschein de Bastida & Bastida 1980: 380, fig. 6; Gordon & Mawatari 1992: 21, pl. 2G, 5F; Hayward & Ryland, 1998: 220, fig. 68; Giachetti et al. 2020: Table S1. Material examined. MACN-In 43875, Comodoro Rivadavia harbour, April 25, 2019, collected by Mariana Abelando. Description. See Lichtschein de Bastida & Bastida (1980). Remarks. Molecular studies have found that B. neritina is a complex of cryptic species (McGovern & Hellberg 2003; Fehlauer-Ale et al. 2013) which still have not been assigned species names (McCann et al. 2019). Distribution. One of the commonest members of fouling assemblages throughout the world, except in polar and subpolar regions (Gordon & Mawatari 1992). Widely recorded in harbours and marinas of Brazil, where it has been regarded as a non-indigenous species (Xavier et al. 2021). Its local distribution includes Mar del Plata, Belgrano (Lichtschein de Bastida & Bastida 1980), Puerto Madryn (Giachetti et al. 2020) and Comodoro Rivadavia (this study) harbours, as well as the Malvinas / Falkland Islands (Hastings 1943), where it is also regarded as a NIS (Schwindt et al. 2020)., Published as part of López-Gappa, Juan, Liuzzi, María G., Castro, Karen L., Bobinac, Magalí & Schwindt, Evangelina, 2022, Fouling bryozoans in Argentine harbours (Southwest Atlantic): new records and the description of a new species, pp. 374-400 in Zootaxa 5205 (4) on page 381, DOI: 10.11646/zootaxa.5205.4.4, http://zenodo.org/record/7307128, {"references":["Linnaeus, C. (1758) Systemae naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differetiis, synonymis, locis. 10 th Edition. Laurentii Salvii, Holmiae, 795 pp. https: // doi. org / 10.5962 / bhl. title. 542","Lichtschein de Bastida, V. & Bastida, R. (1980) Los briozoos de las comunidades incrustantes de puertos argentinos. In: Aritio, L. (Ed.), Proceedings of the 5 th Intermational Congress on Marine Corrosion and Fouling, Marine Biology, Barcelona, Spain. Graficas Orbe, Madrid, pp. 371 - 390.","Gordon, D. P. & Mawatari, S. F. (1992) Atlas of marine-fouling Bryozoa of New Zealand ports and harbours. Miscellaneous Publications New Zealand Oceanographic Institute, 107, 1 - 52.","Hayward, P. J. & Ryland, J. S. (1998) Cheilostomatous Bryozoa. Part 1. Aeteoidea - Cribrilinoidea. Synopses of the British Fauna. New Series. No. 10. In: Barnes, R. S. K. & Crothers, J. H. (Eds.), Field Studies Council, Shrewsbury, pp. 1 - 366.","Giachetti, C. B., Battini, N., Castro, K. L. & Schwindt, E. (2020) Invasive ascidians: How predators reduce their dominance in artificial structures in cold temperate areas. Journal of Experimental Marine Biology and Ecology, 533, 151459. https: // doi. org / 10.1016 / j. jembe. 2020.151459","McGovern, T. M. & Hellberg, M. E. (2003) Cryptic species, cryptic endosymbionts, and geographical variation in chemical defenses in the bryozoan Bugula neritina. Molecular Ecology, 12, 1207 - 1215. https: // doi. org / 10.1046 / j. 1365 - 294 X. 2003.01758. x","Fehlauer-Ale, K. H., Mackie, J. A., Lim-Fong, G. E., Ale, E., Pie, M. R. & Waeschenbach, A. (2013) Cryptic species in the cosmopolitan Bugula neritina complex (Bryozoa, Cheilostomata). Zoologica Scripta, 43, 193 - 205. https: // doi. org / 10.1111 / zsc. 12042","McCann, L. D., McCuller, M. I., Carlton, J. T., Keith, I., Geller, J. B. & Ruiz, G. M. (2019) Bryozoa (Cheilostomata, Ctenostomata, and Cyclostomata) in Galapagos Island fouling communities. Aquatic Invasions, 14, 85 - 131. https: // doi. org / 10.3391 / ai. 2019.14.1.04","Xavier, E. A., Almeida, A. C. S. & Vieira, L. M. (2021) The role of artificial habitats on fouling bryozoan fauna in the southwestern Atlantic. Marine Pollution Bulletin, 167, 112310. https: // doi. org / 10.1016 / j. marpolbul. 2021.112310","Hastings, A. B. (1943) Polyzoa (Bryozoa) I. Scrupocellariidae, Epistomiidae, Farciminariidae, Bicellariellidae, Aeteidae, Scrupariidae. Discovery Reports, 22, 301 - 510.","Schwindt, S., Carlton, J. T., Orensanz, J. M., Scarabino, F. & Bortolus, A. (2020) Past and future of the marine bioinvasions along the Southwestern Atlantic. Aquatic Invasions, 15, 11 - 29. https: // doi. org / 10.3391 / ai. 2020.15.1.02"]}

There is an increasing interest in developing innovative coatings and testing natural products with anti-fouling activity to substitute current highly toxic biocides that have a harmful impact on marine organisms. Bacillus licheniformis species have shown different anti-biofilm and anti-fouling activities in vitro, but so far, its efficacy in field trials has not been tested. For this purpose, the capacity of different extracts of B. licheniformis NCTC 10341T to prevent micro and macro-fouling was first tested in vitro. The methanol cell extract (MCE) inhibited bacterial biofilm formation without significantly affecting planktonic growth and displayed a significant efficacy to prevent larval settlement of the macro-fouler Bugula neritina in vitro without inducing lethality. Additionally, the MCE presented low toxicity against the non-target species Artemia salina. The B. licheniformis MCE was then incorporated in a self-polishing paint at 2 and 5% w/w and tested in a static immersion experiment in the Gulf of Aqaba (northern Red Sea) for 180 days. Fouling coverage decreased by 30% in the 5% MCE-treated panels in comparison with the control panels. Differences in the anti-biofilm activity of the extracts depending on the culture medium highlight the importance of the strict control of culture conditions for the production of biomass with stable bioactive activity. The results indicate the potential of B. licheniformis NCTC 10341T crude extracts for environmentally friendly anti-fouling applications, although a deeper characterization of the bioactive compounds present in the B. licheniformis MCE and its mode of action is required to allow strict control of the activity of the extracts to achieve large-scale industrial production This work was supported by the European Union under Grant FP7-OCEAN-2013 612717 (Low-toxic cost-efficient environment-friendly anti-fouling materials). AM was supported by a predoctoral fellowship from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (ED481A-2015/311). CM was supported by a post-doctoral fellowship from Xunta de Galicia (IN606B-2019/010) SI

Caprella scaura is an invasive amphipod, native to the Indian Ocean, which has already spread to several regions of the world, including the Mediterranean Sea. The present study reports the first occurrence of the species on fish farms cages in Greece, in the Pagasitikos Gulf. Specimens were collected from colonies of the bryozoan Bugula neritina. Basic aspects of the population dynamics of the species, such as the population structure, sex ratio, and size frequency were studied for 13 months and tested for differences between two depth levels (30 cm and 5 m). Population density was significantly different between the two sampled depths. All the demographic categories were present during the whole study period, indicating that the species follows a continuous reproduction pattern in the region. Males were typically larger than females, but females were more abundant in most samples. It seems that the species is well established in the region and is probably moving towards the northern parts of the Aegean Sea.

Kin associations increase the potential for inbreeding. The potential for inbreeding does not, however, make inbreeding inevitable. Numerous factors influence whether inbreeding preference, avoidance, or tolerance evolves, and, in hermaphrodites where both self‐fertilization and biparental inbreeding are possible, it remains particularly difficult to predict how selection acts on the overall inbreeding strategy, and to distinguish the type of inbreeding when making inferences from genetic markers. Therefore, we undertook an empirical analysis on an understudied type of mating system (spermcast mating in the marine bryozoan, Bugula neritina) that provides numerous opportunities for inbreeding preference, avoidance, and tolerance. We created experimental crosses, containing three generations from two populations to estimate how parental reproductive success varies across parental relatedness, ranging from self, siblings, and nonsiblings from within the same population. We found that the production of viable selfed offspring was extremely rare (only one colony produced three selfed offspring) and biparental inbreeding more common. Paternity analysis using 16 microsatellite markers confirmed outcrossing. The production of juveniles was lower for sib mating compared with nonsib mating. We found little evidence for consistent inbreeding, in terms of nonrandom mating, in adult samples collected from three populations, using multiple population genetic inferences. Our results suggest several testable hypotheses that potentially explain the overall mating and dispersal strategy in this species, including early inbreeding depression, inbreeding avoidance through cryptic mate choice, and differential dispersal distances of sperm and larvae., Our goal in this manuscript was to (a) experimentally assess how reproductive success depends on the relatedness of mates, including self, siblings, and nonsiblings within the same population and (b) to estimate inbreeding in natural adult populations using genetic markers. We found that reproductive success was lowest for self‐mating and highest for nonsib mating, and there was little evidence for consistent inbreeding in the field. Our results suggest that inbreeding depression, mate choice, and differential dispersal of sperm and larvae, could all potentially determine the amount of inbreeding and the overall mating and dispersal strategy in this species, and others like it

Offspring sizes vary within populations but the reasons are unclear. Game-theoretic models predict that selection will maintain offspring-size variation when large offspring are superior competitors (i.e., competition is asymmetric), but small offspring are superior colonizers. Empirical tests are equivocal, however, and typically rely on interspecific comparisons, whereas explicit intraspecific tests are rare. In a field study, we test whether offspring size affects competitive asymmetries using the sessile marine invertebrate, Bugula neritina. Surprisingly, we show that offspring size determines whether interactions are competitive or facilitative-large neighbors strongly facilitated small offspring, but also strongly competed with large offspring. These findings contradict the assumptions of classic theory-that is, large offspring were not superior competitors. Instead, smaller offspring actually benefit from interactions with large offspring-suggesting that asymmetric facilitation, rather than asymmetric competition, operates in our system. We argue that facilitation of small offspring may be more widespread than currently appreciated, and may maintain variation in offspring size via negative frequency-dependent selection. Offspring size theory has classically viewed offspring interactions through the lens of competition alone, yet our results and those of others suggest that theory should accommodate positive interactions in explorations of offspring-size variation.

Biofouling is a significant problem in the aquaculture and marine shipping industries; thus, various antifouling methods have been developed to prevent the resultant economic losses. In the present study, the superhydrophobic surface of a lotus leaf was bio-mimicked to achieve antifouling. Specifically, fabric substrates with and without superhydrophobic coatings on the surface were installed on the Tongyeong yacht in December 2020 (group A) and April 2021 (group B), and the coverage of the attached invertebrates was recorded every month until August 2021. The coverage of solitary ascidians (Ascidiella aspersa and Ciona robusta) and branching bryozoans (Bugula neritina) was lower on the coated substrates than on the non-coated ones, and coating or non-coating was significantly correlated with the extent of coverage. Superhydrophobic substrates with a low surface energy and micro–nano dual structure may be unsuitable for the attachment of larvae. Therefore, superhydrophobic coating is a more effective and simpler method of antifouling for certain taxa than other antifouling strategies. However, the antifouling effect of the superhydrophobic substrate in group A reduced after 5 months from the first installation; thus, the durability of the antifouling coating should be further improved, and solving this problem remains a major task, necessitating further research.

Bacteriophage communities associated with humans and vertebrate animals have been extensively studied, but the data on phages living in invertebrates remain scarce. In fact, they have never been reported for most animal phyla. Our ultrastructural study showed for the first time a variety of virus-like particles (VLPs) and supposed virus-related structures inside symbiotic bacteria in two marine species from the phylum Bryozoa, the cheilostomesBugula neritinaandParalicornia sinuosa. We also documented the effect of VLPs on bacterial hosts: we explain different bacterial ‘ultrastructural types’ detected in bryozoan tissues as stages in the gradual destruction of prokaryotic cells caused by viral multiplication during the lytic cycle. We speculate that viruses destroying bacteria regulate symbiont numbers in the bryozoan hosts, a phenomenon known in some insects. We develop two hypotheses explaining exo- and endogenous circulation of the viruses during the life-cycle ofB. neritina. Finally, we compare unusual ‘sea-urchin’-like structures found in the collapsed bacteria inP. sinuosawith so-called metamorphosis associated complexes (MACs) known to trigger larval metamorphosis in a polychaete worm.ImportanceComplex symbiotic systems, including metazoan hosts, their bacterial symbionts and bacteriophages are widely studied using vertebrate models whereas much less is known about invertebrates. Our ultrastructural research revealed replication of the viruses and/or activation of virus related elements in the bacterial symbionts inhabiting tissues of the marine colonial invertebrates (phylum Bryozoa). The virus activity in the bacterial cells that are believed to be transmitted exclusively vertically is of a special importance. In addition, in the bacterial symbionts of one of the bryozoan hosts we observed the massive replication of the structures seemingly related to the Metamorphosis associated complexes (MAC). To our knowledge, MACs were never reported in the animal prokaryotic symbionts. Our findings indicate that Bryozoa may be new suitable model to study the role of bacteriophages and phage-related structures in the complex symbiotic systems hosted by marine invertebrates.

Community assembly may not follow predictable successional stages, with a large fraction of the species pool constituted by potential pioneering species and successful founders defined through lottery. In such systems, priority effects may be relevant in the determination of trajectories of developing communities and hence diversity and assemblage structure at later advanced states. In order to assess how different founder species may trigger variable community trajectories and structures, we conducted an experimental study using subtidal sessile assemblages as model. We manipulated the identity of functionally different founders and initial colony size (a proxy of the time lag before the arrival of later species), and followed trajectories. We did not observe any effects of colony size on response variables, suggesting that priority effects take place even when the time lag between the establishment of pioneering species and late colonizers is very short. Late community structure at experimental panels that started either with the colonial ascidian Botrylloides nigrum, or the arborescent bryozoan Bugula neritina, was similar to control panels allowed natural assembling. In spite of high potential for fast space domination, and hence negative priority effects, B. nigrum suffered high mortality and did not persist throughout succession. Bugula neritina provided complex physical microhabitats through conspecific clustering that have enhanced larval settlement of late species arrivals, but no apparent facilitation was observed. Differently, panels founded by the encrusting bryozoan Schizoporella errata led to different and less diverse communities compared to naturally assembled panels, evidencing strong negative priority effects through higher persistence and space preemption. Schizoporella errata founder colonies inhibited further conspecific settlement, which may greatly relax intraspecific competition, allowing resource allocation to colony growth and space domination, thus reducing the chances for the establishment of other species.

The invasive caprellid Caprella scaura Templeton, 1836 is rapidly spreading along marinas of Southern Spain, becoming one of the dominant species of the macrofoulers associated to bryozoans and hydroids of communities in harbours. In order to explore the abundance and distribution patterns of the species in the different habitats available in marinas (floating pontoons, buoys and hull boats), a spatial study was conducted in Cádiz Marina (Puerto América) during two sampling periods (July and November). The bryozoan Bugula neritina was present in all the habitats and were selected as a substrate for comparison among habitats. In the floating pontoons, the single species C. scaura represented more than 60% of all the epifaunal individuals (including other crustaceans, polychaetes, molluscs and pycnogonids), both in July and November. In the boats and the buoys, C. scaura was dominant also in November, while gammarideans dominated in July. Abundance of C. scaura was significantly higher in floating pontoons than in hull boats. The attached caprellids to the boats are frequently exposed to strong water currents originated by boat displacements during local trips, so the results of the present study seem to indicate a preference of C. scaura by more stable substrates and non-exposed waters within the marina, such as floating pontoons. Ministerio de Economía y Competitividad CGL2011-22474 Junta de Andalucía P11-RNM-7041

Two new polyphenols, talaversatilis A (1) and B (2), together with fifteen known compounds (3–17) were isolated from the extract of the culture broth of a soft coral-derived fungus Talaromyces sp. SCSIO 041201. The structures of these compounds were elucidated by the extensive analyses of spectroscopic data and by comparison with the reported literature. Antifouling and antibacterial activities of all purified compounds were tested and evaluated. Compounds 5 and 6 showed antifouling activity towards Bugula neritina larva, with LC50 values of 3.86 μg/mL and 3.05 μg/mL, respectively. Compounds 7, 8, 10 and 13 exhibited significant antibacterial activities against E. coli, MRSA, S. aureus and E. faecalis, with MIC values ranging from 0.45 to 15.6 μg/mL.

Bugula neritina is a sessile marine bryozoan with a pelagic larval stage. Larvae frequently settle on boat hulls, facilitating the introduction of B. neritina to bays and estuaries worldwide. Adrenergic agonists, such as norepinephrine, inhibit larval settlement in a variety of marine invertebrate species, including B. neritina. Light also inhibits larval settlement of B. neritina, yet the underlying mechanisms by which light and adrenergic compounds exert their effects on larvae are largely unknown. Octopamine is considered the invertebrate analog of norepinephrine, and may be one endogenous compound involved in larval settlement pathways. In this study, we investigated the effects of norepinephrine and the adrenergic antagonist phentolamine on larval settlement, and found that norepinephrine inhibited larval attachment and increased larval swimming behavior, while phentolamine increased larval attachment and decreased larval swimming behavior. We used fluorescent labeling and immunocytochemistry to localize sensory system components, and found that larvae possess adrenergic-like receptors and octopamine-like immunoreactivity. We also exposed larvae to phentolamine in both dark and light conditions, and found that light inhibited larval attachment, but phentolamine blocked those inhibitory effects. Based on these results, we put forth a putative mechanistic explanation for the effects of both light and adrenergic compounds on B. neritina larval settlement behavior. This study sheds light on previously unknown pathways underlying larval settlement behavior of bryozoans, and may aid in the development of effective, non-toxic biofouling control strategies.

Along the Turkish coast, Bugulidae family represented with tree valid genera, Bugula, Bugulina and Crisularia, contains mostly common fouling species in shallow and deep water. Five species belonging to two genera (Bugula neritina, Bugulina flabellata, Bugulina simplex, Bugulina stolonifera, Bugulina fulva) were investigated during different sampling periods. This study provides descriptions, illustrations, and information about ecological characteristics and biogeographical distributions of the above mentioned species. Bugulina fulva was reported for the first time from the Eastern Mediterranean coast of Turkey (Marmaris).

Global urbanization and plastic pollution has increased the availability and variety of substrates for sessile organisms, and are intensively used by invasive species for settlement. Despite extensive literature describing the strong association between artificial structures and invasive species, little effort has been directed towards identifying the larval traits that favor this selection. Larval selection and settlement are crucial as larvae actively search and interpret environmental cues to identify suitable habitats to settle. The aim of this research was to investigate if invertebrate larvae have a preference for a particular anthropogenic substrate, and how pre-settlement behaviors vary when encountering different substrates. We used two invasive bryozoan species, Bugula flabellata and Bugula neritina, which are commonly found in urbanized areas around the world. Energy expenditure during planktonic and benthonic stages, pre-settlement swimming/exploring behaviors, settlement and larval selectivity were quantified under laboratory conditions on different substrates (concrete, wood, polystyrene, polyvinyl chloride, polyethylene terephthalate and polycarbonate). The energy expenditure measured was higher in planktonic larvae than in early settled larvae. Larvae of both species swam less and explored more when exposed to plastic surfaces, suggesting a preference for this substrate and resulting in lower energy expenditures associated with searching for habitat. Larvae actively chose to settle on plastics rather than on wood or concrete substrates. The results suggest that for Bugula larvae, the likelihood of colonizing plastic surfaces is higher than other materials commonly found in urbanized coastal areas. The more quickly they adhere to artificial substrates the lower the energy expenditure, contributing to higher fitness in these individuals. The strong preference of invertebrate larvae for plastics can potentially extend the distribution range of many invasive marine species as they are able to travel long distances attached to floating debris. This phenomenon will likely exacerbate the introduction of exotic species into novel habitats.

AIM: Recent work has documented latitudinal gradients of biotic resistance, revealing diminished invasion success in the tropics as compared to the temperate zone. However, no studies have explored the biogeography of biotic resistance simultaneously with propagule pressure, which can greatly influence invasion dynamics and covary with latitude. LOCATION: 9–41° latitude, north‐western Atlantic seagrass beds. METHODS: We conducted field experiments to test the interactive effects of propagule pressure (experimentally placed recruits) and biotic resistance (predation) on invader performance in temperate and tropical seagrass beds. For these experiments, we used marine invertebrate propagules from bryozoans (Bugula neritina) and tunicates (Didemnum spp.). We also quantified natural recruitment with and without exposure to predators. RESULTS: Surprisingly, predation substantially reduced invader survival at almost all latitudes. Overall, invaders experienced 15%–27% survival with predation as opposed to 75%–87% survival without predation. These patterns did not change when we increased local scale propagule pressure of Bugula by over 2‐fold. However, predation had no effect on invader survival in Florida, where natural recruitment was up to 500‐fold greater than other sites. We also measured substantial in situ recruitment of Bugula onto bare experimental surfaces that was not diminished with exposure to predators at mid‐latitudes, suggesting a regional scale predator swamping effect. CONCLUSIONS: Contrary to recent findings of latitudinal variation in biotic resistance, we found that predation strongly reduced invader success in both temperate and tropical seagrass beds. However, our results also indicate that propagule pressure (natural recruitment) can influence invasion at the regional scale to overwhelm native communities. Our data suggest that predation and propagule pressure act at varying spatial scales to affect biogeographic patterns of invasion. The importance of latitudinal variation in these interactions is largely untested but deserves attention given that globalization will continue to facilitate opportunities for invasion.

Bryozoans are the major component of marine macro-fouling communities. In the study, the relations between bryozoan species and environmental variables were investigated at seven stations along the Aegean coast in August and December 2015. Constant bryozoan species in both sampling periods were Bugula neritina, Amathia verricillata, Shizoporella errata, Cryptosula pallasiana and Celleporaria bnamea. Their relationship with physicochemical variables (Temperature, salinity, pH, dissolved oxygen, ammonium, nitrite and nitrate nitrogen, orthophosphate phosphorous, total phosphate, chlorophyll-alpha) were analysed by means of logistic regression analysis. The result showed that temperature with B. neritina; NH4-N, oPO(4)-P and TPO4-P with A verticiliora; dissolved oxygen concentrations with S. errata and C. bnamea were positively related (p < 0.05).

The bryozoan Bugula neritina is a cosmopolitan marine fouling species that causes major fouling problems in sub-tropical waters. Settlement of B. neritina larvae can be triggered without an obvious external cue. Here, the negative regulatory role of nitric oxide (NO) during larval settlement of B. neritina was demonstrated to be mediated by cyclic guanosine monophosphate (cGMP). Although the regulatory role of the NO-p38 MAPK signaling axis in larval settlement was not evident, inhibition of nitric oxide synthase (NOS) led to the deactivation of p38 MAPK. Exclusive localization of NO and NO signaling components in sensory-related organs of the larvae is consistent with its signal transduction function in metamorphosis. Overall, this study provides new insights into the regulatory roles of the NO-p38MAPK/cGMP pathway in B. neritina settlement.

Bugula neritina is a common invasive cosmopolitan bryozoan that harbors (like many sessile marine invertebrates) a symbiotic bacterial (SB) community. Among the SB of B. neritina, “Candidatus Endobugula sertula” continues to receive the greatest attention, because it is the source of bryostatins. The bryostatins are potent bioactive polyketides, which have been investigated for their therapeutic potential to treat various cancers, Alzheimer’s disease, and AIDS. In this study, we compare the metagenomics sequences for the 16S ribosomal RNA gene of the SB communities from different geographic and life cycle samples of Chinese B. neritina. Using a variety of approaches for estimating alpha/beta diversity and taxonomic abundance, we find that the SB communities vary geographically with invertebrate and fish mariculture and with latitude and environmental temperature. During the B. neritina life cycle, we find that the diversity and taxonomic abundances of the SB communities change with the onset of host metamorphosis, filter feeding, colony formation, reproduction, and increased bryostatin production. “Ca. Endobugula sertula” is confirmed as the symbiont of the Chinese “Ca. Endobugula”/B. neritina symbiosis. Our study extends our knowledge about B. neritina symbiosis from the New to the Old World and offers new insights into the environmental and life cycle factors that can influence its SB communities, “Ca. Endobugula,” and bryostatins more globally.

Oxygen-poor habitats are increasingly common in aquatic environments. Human activities are accelerating the spread of oxygen-poor environments, yet the way in which larvae avoid low-oxygen conditions remains poorly resolved. For organisms with a sessile or sedentary adult phase, habitat selection is crucial, and many organisms show sophisticated responses to various habitat cues during colonization. Whether oxygen availability serves as such a cue is unknown, yet increasingly, it seems that oxygen is an essential limiting resource in some systems. In a series of experiments, we manipulated oxygen levels during dispersal and colonization in larvae of the model marine invertebrate Bugula neritina in the laboratory. We found that, in the presence of lower oxygen levels, larvae reduce the time spent in habitat exploration and that they delay settlement. We also found that larvae avoid hypoxic water (positive oxytaxis)-the first such demonstration for marine larvae. All of these behaviors may decrease the likelihood of colonizing low-oxygen habitats in nature. Our results suggest that marine invertebrate larvae, in this species at least, can use oxygen availability as an initial cue for habitat selection but that additional factors (e.g. biofilms) determine settlement patterns.

In marine benthic communities, phenotypic responses to contact competition are well resolved, but the causes and consequences of non-contact competition remain unclear. Here, we used the arborescent bryozoan Bugula neritina to firstly identify whether colonies change their phenotype as a result of non-contact competition, and then understand the mechanism behind the changes. Secondly, we determined the phenotypes that change in response to non-contact competition, with focus on changes in the feeding structure, viz. the lophophore. Lastly, we used a reciprocal transplant design to test whether phenotypic responses to non-contact competition reduce its negative effects. We found that phenotypic responses to non-contact competition were mediated by the biological effects of conspecific neighbours, but were also determined by the physical effects associated with increased density. Further, we found that colonies grown in high conspecific density environments were smaller (though more elongated for their size) and had smaller lophophores than colonies from low conspecific density treatments. However, we found no evidence that such phenotypic responses constituted adaptive plasticity; instead, individuals that experienced non-contact competition always performed worse than individuals that had not, and the effects of exposure to non-contact competition were additive. Our study suggests that non-contact competition is an important and persistent process in benthic marine communities, but that phenotypic plasticity, though present, does not buffer individuals from the negative effects of this process.

We examine the relationship between adult body form (sheet vs. arborescent) and larval settlement in colonial animals. Because thin sheet forms are more susceptible to overgrowth than arborescent forms, we predict that larvae of sheet forms should preferentially settle in refuges from competitors. On both natural and artificial substrata, the larvae of the sheet form (Mem- branipora membranacea) settled more often on high spots, which could serve as refuges from competition. The ar- borescent forms (Bugula neritina and Distaplia occiden- talis) settled around the bases of bumps more frequently than would be expected by chance. For many arborescent forms, their most vulnerable periods are the days im- mediately following settlement, when individuals can be consumed easily by predators or dislodged by physical disturbances. Settlement in a crevice (base of a bump) would provide protection from the bulky mouthparts of predators. Moreover, dislodgment would be less likely than if settlement had occurred on flat locations, such as the tops of bumps or the areas between bumps.

β-Branching is an expansion upon canonical polyketide synthase extension that allows for the installation of diverse chemical moieties in several natural products. Several of these moieties are unique among natural products, including the two vinyl methylesters found in the core structure of bryostatins. This family of molecules is derived from an obligate bacterial symbiont of a sessile marine bryozoan, Bugula neritina. Within this family, bryostatin 1 has been investigated as an anticancer, neuroprotective, and immunomodulatory compound. We have turned to the biosynthetic gene cluster within the bacterial symbiont to investigate the biosynthesis of bryostatins. Recent sequencing efforts resulted in the annotation of two missing genes: bryT and bryU. Using novel chemoenzymatic techniques, we have validated these as the missing enoyl-CoA hydratase and donor acyl carrier protein, essential components of the β-branching cassette of the bryostatin pathway. Together, this cassette installs the vinyl methylester moieties essential to the activity of bryostatins.

The first record from Sicily of the introduced facelinid nudibranch Godiva quadricolor allowed the detection of trophic relationships with the polycerid Polycera hedgpethi, another non-native nudibranch, and with two bryozoan species, namely the naturalized Cheilostomatida Bugula neritina and the cryptogenic Ctenostomatida Amathia verticillata. The settlement of both nudibranchs was presumably promoted by a trophic shift of P. hedgpethi from the natural prey B. neritina towards the largely available and not exploited A. verticillata. This short food web, without evident links with native fauna and having G. quadricolor as the top predator, is described. A DNA barcoding approach was used to confirm the identity of this facelinid species and to explore the possible genetic divergence occurring among the samples analysed.