Inbreeding is a potent evolutionary force shaping the distribution of genetic variation within and among populations of plants and animals. Yet, our understanding of the forces shaping the expression ...and evolution of nonrandom mating in general, and inbreeding in particular, remains remarkably incomplete. Most research on plant mating systems focuses on self-fertilization and its consequences for automatic selection, inbreeding depression, purging, and reproductive assurance, whereas studies of animal mating systems have often assumed that inbreeding is rare, and that natural selection favors traits that promote outbreeding. Given that many sessile and sedentary marine invertebrates and marine macroalgae share key life history features with seed plants (e.g., low mobility, modular construction, and the release of gametes into the environment), their mating systems may be similar. Here, we show that published estimates of inbreeding coefficients (F
IS) for sessile and sedentary marine organisms are similar and at least as high as noted in terrestrial seed plants. We also found that variation in FIS within invertebrates is related to the potential to selffertiliz, disperse, and choose mates. The similarity of F
IS for these organismal groups suggests that inbreeding could play a larger role in the evolution of sessile and sedentary marine organisms than is currently recognized. Specifically, associations between traits of marine invertebrates and F
IS suggest that inbreeding could drive evolutionary transitions between hermaphroditism and separate sexes, direct development and multiphasic life cycles, and external and internal fertilization.
Molluscs are the invertebrates with the highest level of morphological adaptation, allowing their establishment in the majority of aquatic environments. In fact, the highest fitness level is achieved ...by those species, such as bivalves, adapted to live on cryptic ecosystems build by themselves. In order to describe the diversity of cryptic bivalve molluscs in two sampling areas in the western coast of the Gulf of Venezuela (Kazuzain and Porshoure), samples were manually collected in June and July 2010, respectively, by snorkelling in random coralline rocks (3-5m depth), and stored them in 10% formalin for transportation. In the laboratory, the rocks were fragmented and all organisms within removed. Diversity was determined by the Shannon-Wiener index for each locality, and the Kruskal-Wallis test was used to compare the bivalves composition between both localities in order to establish a possible significant difference (p<0.05). Five families, eight genera and ten species were found (n=53). Lithophaga corrugata, Lioberus castaneus, Gregariella coralliophaga and Choristodon robustus are reported as new records for Venezuela; while Leiosolenus appendiculatus, Lithophaga teres and Malleus candeanus are new records for the Maracaibo Lake System. No significant difference was found between the studied communities (p=0.1587). The specimens remain in the invertebrates collection of the Biology Museum, La Universidad del Zulia (MBLUZ), Maracaibo, Venezuela. PUBLICATION ABSTRACT
Aquaculture contributes more than one-third of the animal protein from marine sources worldwide. A significant proportion of aquaculture products are derived from marine protostomes that are commonly ...referred to as ‘marine invertebrates’. Among them, penaeid shrimp (Ecdysozosoa, Arthropoda) and bivalve molluscs (Lophotrochozoa, Mollusca) are economically important. Mass rearing of arthropods and molluscs causes problems with pathogens in aquatic ecosystems that are exploited by humans. Remarkably, species of corals (Cnidaria) living in non-exploited ecosystems also suffer from devastating infectious diseases that display intriguing similarities with those affecting farmed animals. Infectious diseases affecting wild and farmed animals that are present in marine environments are predicted to increase in the future. This paper summarizes the role of the main pathogens and their interaction with host immunity, with a specific focus on antimicrobial peptides (AMPs) and pathogen resistance against AMPs. We provide a detailed review of penaeid shrimp AMPs and their role at the interface between the host and its resident/pathogenic microbiota. We also briefly describe the relevance of marine invertebrate AMPs in an applied context.
This article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’.
Jellyfish Blooms Purcell, Jennifer E; Angel, Dror L
2010, Letnik:
212
eBook
This volume provides an identification key for the ephyrae of 18 common scyphozoan species, documents the Mediterranean-wide bloom of the invasive ctenophore Mnemiopsis leidyi, and addresses the ...direct effects of ocean acidification on jellyfish.
Neonicotinoids, broad-spectrum systemic insecticides, are the fastest growing class of insecticides worldwide and are now registered for use on hundreds of field crops in over 120 different ...countries. The environmental profile of this class of pesticides indicate that they are persistent, have high leaching and runoff potential, and are highly toxic to a wide range of invertebrates. Therefore, neonicotinoids represent a significant risk to surface waters and the diverse aquatic and terrestrial fauna that these ecosystems support. This review synthesizes the current state of knowledge on the reported concentrations of neonicotinoids in surface waters from 29 studies in 9 countries world-wide in tandem with published data on their acute and chronic toxicity to 49 species of aquatic insects and crustaceans spanning 12 invertebrate orders. Strong evidence exists that water-borne neonicotinoid exposures are frequent, long-term and at levels (geometric means=0.13μg/L (averages) and 0.63μg/L (maxima)) which commonly exceed several existing water quality guidelines. Imidacloprid is by far the most widely studied neonicotinoid (66% of the 214 toxicity tests reviewed) with differences in sensitivity among aquatic invertebrate species ranging several orders of magnitude; other neonicotinoids display analogous modes of action and similar toxicities, although comparative data are limited. Of the species evaluated, insects belonging to the orders Ephemeroptera, Trichoptera and Diptera appear to be the most sensitive, while those of Crustacea (although not universally so) are less sensitive. In particular, the standard test species Daphnia magna appears to be very tolerant, with 24–96hour LC50 values exceeding 100,000μg/L (geometric mean>44,000μg/L), which is at least 2–3 orders of magnitude higher than the geometric mean of all other invertebrate species tested. Overall, neonicotinoids can exert adverse effects on survival, growth, emergence, mobility, and behavior of many sensitive aquatic invertebrate taxa at concentrations at or below 1μg/L under acute exposure and 0.1μg/L for chronic exposure. Using probabilistic approaches (species sensitivity distributions), we recommend here that ecological thresholds for neonicotinoid water concentrations need to be below 0.2μg/L (short-term acute) or 0.035μg/L (long-term chronic) to avoid lasting effects on aquatic invertebrate communities. The application of safety factors may still be warranted considering potential issues of slow recovery, additive or synergistic effects and multiple stressors that can occur in the field. Our analysis revealed that 81% (22/27) and 74% (14/19) of global surface water studies reporting maximum and average individual neonicotinoid concentrations respectively, exceeded these thresholds of 0.2 and 0.035μg/L. Therefore, it appears that environmentally relevant concentrations of neonicotinoids in surface waters worldwide are well within the range where both short- and long-term impacts on aquatic invertebrate species are possible over broad spatial scales.
•Neonicotinoids in surface waters often exceed existing regulatory guidelines.•Environmental persistence indicates regulatory thresholds using acute toxicity tests may underestimate toxic potential.•Daphnia magna, industry standard, is at least1000 times less sensitive than mean of all other aquatic invertebrates.•Large differences in LEC50 values relate to sensitivity among species not potency among neonicotinoids.•Predict effects on communities at water concentrations ≥0.2 (max) or 0.035μg/L (avg)
PDF
