scholarly journals Dreissenids’ breaking loose: differential attachment as a possible driver of the dominance shift between two invasive mussel species

2021 ◽  
Author(s):  
Anouk D’Hont ◽  
Adriaan Gittenberger ◽  
A. Jan Hendriks ◽  
Rob S. E. W. Leuven
Keyword(s):  
Dreissena Polymorpha ◽  
Laboratory Experiments ◽  
Species Differences ◽  
The Other ◽  
Attachment Rate ◽  
Shell Size ◽  
Dreissena Bugensis ◽  
Byssal Thread ◽  
Attachment Strength ◽  
Invasive Mussel

AbstractPonto-Caspian dreissenids are notorious freshwater invaders. Recently, widespread observations show a dominance shift from the early invader, Dreissena polymorpha, to its successor, Dreissena bugensis. These observations likely reflect congeneric species differences in physiological and behavioural traits. Here, we assessed the mussel attachment strength, attachment rate, and the mode of byssal failure as trait differences that could potentially contribute to dominance shifts. The attachment traits were measured in field and laboratory experiments. Fouling plates were deployed in the Rhine-Meuse river delta and dreissenids were collected and acclimatised in 60 L non-aerated freshwater tanks. Attachment strength was positively correlated with shell size. The attachment strength of D. bugensis was significantly greater compared to slower growing D. polymorpha individuals of a dreissenid field assemblage. This corresponded to the superior byssal thread morphology of D. bugensis (i.e. higher number and two times wider byssal threads). Moreover, our results indicated that byssal threads of D. bugensis are stronger than those of D. polymorpha, as the latter ruptured more often. Additionally, D. bugensis had a significantly lower attachment rate than D. polymorpha. Having a greater attachment strength gives D. bugensis an advantage when it comes to withstanding currents and predators. On the other hand, not being attached allows an individual to actively move around. This would allow them to move away from fast changing unfavourable environmental conditions. These attachment traits indicate competitive benefits for D. bugensis over D. polymorpha, therefore possibly contributing to the dominance shifts.

scholarly journals The impact of dreissenid mussels on growth of the fragile papershell (Leptodea fragilis), the most abundant unionid species in Lake Erie

2015 ◽  
Vol 93 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Robert A. Krebs ◽  
Elizabeth M. Barkett ◽  
Matthew T. Begley
Keyword(s):  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Freshwater Mussel ◽  
Species Competition ◽  
Western Basin ◽  
Dreissena Bugensis ◽  
Byssal Thread ◽  
Quagga Mussels ◽  
Dreissenid Mussels ◽  
The Impact

The arrival of zebra mussels (Dreissena polymorpha (Pallas, 1771)) and subsequently quagga mussels (Dreissena bugensis Andrusov, 1897) (Dreissenidae) in the Great Lakes in the 1980s induced many changes, most notably the devastation of native freshwater mussel species. Recently, empty shells of the fragile papershell (Leptodea fragilis (Rafinesque, 1820)) have become common, particularly in the western basin of Lake Erie, suggesting that this fast-growing species may be increasing in numbers in the lake. To examine continued competition with dreissenids, shell age and length of L. fragilis were used to contrast lifespan and growth rate, estimated as the slope of age on shell length, for shells from two beach localities where byssal threads were present on most shells and two sites where dreissenids were rare or absent. Few recent shells from Lake Erie beaches exceeded 5 years of age, and byssal thread counts were more numerous on older shells. Growth and lifespan were estimated to be significantly lower where dreissenid mussels remained numerous than when measured either from historic collections along Lake Erie or from protected populations. Therefore, even for this early-reproducing species, competition from dreissenids may continue to interfere with growth and shorten lifespan, which are effects few other unionid species can likely tolerate sufficiently to sustain population growth.

A wall jet to measure the attachment strength of zebra mussels

1995 ◽  
Vol 52 (1) ◽  
pp. 126-135 ◽  
Author(s):  
Josef Daniel Ackerman ◽  
C. Ross Ethier ◽  
Jan K. Spelt ◽  
D. Grant Allen ◽  
Catherine M. Cottrell
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Zebra Mussels ◽  
Artificial Substrates ◽  
Environmentally Benign ◽  
Wall Jet ◽  
Dreissena Bugensis ◽  
Marine Bivalves ◽  
Attachment Strength ◽  
The Mean

A wall jet is presented as a novel means of measuring the attachment strength of zebra mussels. Attachment strength was inferred from a fluid detachment parameter (DP), defined as the nominal wall shear stress at the detachment site × mussel length2. DP varied significantly on natural and artificial substrates: in tests with 288 Dreissena bugensis (≈8–10 mm long), the mean (±SE) DP was 8.9 ± 0.9 mPa∙m2 on limestone/dolomite, 5.6 ± 0.5 mPa∙m2 on polyvinylchloride, 4.3 ± 0.4 mPa∙m2 on stainless steel, 4.2 ± 0.5 mPa∙m2 on aluminum, and 2.5 ± 0.3 mPa∙m2 on polymethylmethacrylate (Plexiglas). The attachment strength of postlarval mussels (plantigrades; <1 mm) was two orders of magnitude less than adult mussels. These results were validated with conventional tensile loadings, in which 633 Dreissena bugensis and 26 Dreissena polymorpha were pulled off substrates with a calibrated force scale. The tensile loadings results were comparable with those of marine bivalves. Good correlation between pull-off force and DP was observed. Information of this nature is useful for the implementation of environmentally benign zebra mussel controls.

Effect of turbulence on the mortality of zebra mussel veligers

2003 ◽  
Vol 81 (6) ◽  
pp. 1063-1069 ◽  
Author(s):  
C R Rehmann ◽  
J A Stoeckel ◽  
D W Schneider
Keyword(s):  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Laboratory Experiments ◽  
Small Scale ◽  
Bubble Plume ◽  
Acute Effects ◽  
Shell Size ◽  
Control Scheme ◽  
Scale Turbulence ◽  
Rate Of Dissipation

Small-scale turbulence can increase the mortality of zebra mussel (Dreissena polymorpha) veligers. Laboratory experiments were conducted in which veligers were subjected to turbulence due to a bubble plume and the rate of dissipation of turbulent kinetic energy was measured directly. The ratio d* of the shell size and the Kolmogorov length, the size of the smallest eddy in the velocity field, is introduced to quantitatively assess whether turbulence can affect larvae. The laboratory experiments show that mortality increases when d* exceeds 0.9, that is, when the size of the larvae is comparable with or larger than the smallest eddy. The laboratory results are used to show that turbulence can increase veliger mortality in streams and to evaluate the possibility of using bubble screens as a dispersal barrier to control zebra mussels in rivers. If the mortality is due to acute effects of turbulence (taken to be exposure on the order of minutes), the control scheme would work, but if the mortality is due to longer-term exposure, using bubble screens would not be practical.

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

Species differences in effect of gram-negative endotoxin on circulation

1961 ◽  
Vol 200 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Hiroshi Kuida ◽  
Robert P. Gilbert ◽  
Lerner B. Hinshaw ◽  
Joel G. Brunson ◽  
Maurice B. Visscher
Keyword(s):  
Pulmonary Artery ◽  
Right Ventricular ◽  
Species Differences ◽  
The Other ◽  
Short Segment ◽  
Gram Negative ◽  
Microscopic Studies ◽  
Significant Mechanism ◽  
Dramatic Fall ◽  
Made In

Studies were made in 5 monkeys, 7 rabbits, and 33 cats of the effect of gram-negative endotoxin on aortic, pulmonary artery (PAP), and portal venous (PVP) pressures; and on changes in weight of a short segment of intestine. Studies of blood pooling were also made in 12 cats. The responses in these species were compared with those previously observed in the dog. Although variable degrees of hypotension developed at one time or another in all animals following injection of endotoxin, the early precipitous hypotension that characteristically occurs in the dog was observed only in the cat. However, in this species the dramatic fall in pressure could be ascribed to pulmonary vascular constriction and acute right ventricular hypertension and failure, and not to splanchnic pooling. PAP also became elevated in the monkey and the rabbit, but usually was of lesser magnitude and did not appear to explain the development of the relatively late hypotension that occurred in these species. The absence of significant increases in gut weight and the minor increments in PVP in all animals indicate that in none of these species is hepatic vein constriction and splanchnic pooling a significant mechanism in producing early shock as it is in the dog. Pathologic gross and microscopic studies in the monkey and gross examinations in the other species supported this conclusion.

scholarly journals A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1251 ◽  
Author(s):  
Su-Chin Chen ◽  
Samkele Tfwala ◽  
Tsung-Yuan Wu ◽  
Hsun-Chuan Chan ◽  
Hsien-Ter Chou
Keyword(s):  
Laboratory Experiments ◽  
Horseshoe Vortex ◽  
Flow Fields ◽  
Bridge Pier ◽  
The Other ◽  
Bridge Piers ◽  
Vortex Strength ◽  
Numerical Tests ◽  
Scour Hole ◽  
New Type

A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

Effects of juvenile hormone mimics on the codling moth Cydia Pomonella (L.) (Lep., Olethreutidae)

1973 ◽  
Vol 63 (1) ◽  
pp. 7-16 ◽  
Author(s):  
I. Gelbič ◽  
F. Sehnal
Keyword(s):  
Juvenile Hormone ◽  
Laboratory Experiments ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
The Other ◽  
Wide Range ◽  
Juvenile Hormone Analogues ◽  
Juvenile Hormone Mimics

AbstractLaboratory experiments with juvenile hormone analogues on Cydia pomonella (L.) showed that Cecropia C17 juvenile hormone (methyl 10,ll-epoxy-3,7,ll-trimethyl-2,6-dodecadienoate) was the most active of the 28 compounds tested. When applied to four-hour-old eggs at 0.1 μg/egg, the hormone caused 100% failure in embryogenesis, while the other compounds were at least five times less effective. Depending on the time since ecdysis and the dose, juvenile hormone mimics applied to last-instar larvae resulted in a wide range of intermediate forms. Against three-day-old last-instar larvae, the Cecropia C17 hormone gave 100% inhibition of development at a dose of 1 μg/larva, while three other compounds (methyl 10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate, ethyl 11-chloro-3,7,11-trimethyl-2-dodecenoate and ethyl 3,7,11-tri-methyl-2,4-dodecadienoate) gave the same effect at 2–5 μg/larva. Against newly emerged adults, the last two compounds at 10–50 μg/insect reduced fecundity and fertility to 0–81% and 0–50%, respectively, of their normal levels.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

Thinking orientation and preference for research methodology

2016 ◽  
Vol 33 (6) ◽  
pp. 437-446 ◽  
Author(s):  
Feisal Murshed ◽  
Yinlong Zhang
Keyword(s):  
Research Methodology ◽  
Design Methodology ◽  
Laboratory Experiments ◽  
Qualitative Methodology ◽  
Marketing Research ◽  
Cross Cultural ◽  
The Other ◽  
Content Type ◽  
Holistic Thinking ◽  
Practical Implications

Purpose This research aims to investigate how preference for marketing research methodology (quantitative vs qualitative) is contingent on the thinking orientation (analytic vs holistic) of the researchers. Design/methodology/approach Thinking orientation was measured and then manipulated in laboratory experiments. Cross-cultural evidence was sought by comparing Western and East Asian participants. Findings Results demonstrate that researchers with an analytic (holistic) thinking orientation tend to perceive quantitative (qualitative) methodology more favorably. Further, the need to offer reasons in support of the choice strengthened the effect of thinking orientation. Practical implications Understanding researchers’ preferences for one research methodology over the other has broad relevance for external constituents, as it involves a great deal of managerial commitment in terms of time and money and can affect the results of the research. Originality/value This is the first study to investigate factors that underlie researchers’ choice regarding research methodology, and it also extends the literature on analytic versus holistic thinking orientation in the marketing field.

Morphological evolution of the bivalvePtychomyathrough the Lower Cretaceous of Argentina

Paleobiology ◽  
2018 ◽  
Vol 44 (1) ◽  
pp. 101-117
Author(s):  
Pablo S. Milla Carmona ◽  
Darío G. Lazo ◽  
Ignacio M. Soto
Keyword(s):  
Time Series ◽  
Morphological Variation ◽  
Morphological Evolution ◽  
The Other ◽  
Upward Trend ◽  
Shell Size ◽  
Evolutionary Patterns ◽  
Upper Hauterivian ◽  
Patterns And Processes ◽  
Early Late

AbstractThe complex morphological evolution of the bivalvePtychomyathroughout the well-studied Agrio Formation in the Neuquén Basin (west-central Argentina, lower/upper Valanginian–lowest Barremian) constitutes an ideal opportunity to study evolutionary patterns and processes occurring at geological timescales. Ptychomyais represented in this unit by four species, the morphological variation of which needs to be temporally assessed to obtain a thorough picture of the evolution of the group. Here we use geometric morphometrics to measure variation in shell outline, ribbing pattern, and shell size in these species. We bracket the ages of our samples using a combination of ammonoid biostratigraphy and absolute ages and study the anagenetic pattern of evolution of each trait by means of paleontological time-series analysis and change tracking. We find that evolution inPtychomyais mostly speciational, as the majority of traits show stasis, with the exceptions of shell size inP. coihuicoensisand shell outline inP. windhauseni, which seem to evolve directionally toward larger and higher shells, respectively.Ptychomyadisplays changes in its average morphology and disparity, which are the result of a mixture of taxonomic turnover and mosaic evolution of traits. Pulses of speciation would have been triggered by ecological opportunity, as they occur during the recovery of shallow-burrowing bivalve faunas after dysoxic events affecting the basin. On the other hand, the presence of directional patterns of evolution inP. coihuicoensisandP. windhauseniseems to be the result of a general shallowing-upward trend observed in the basin during the upper Hauterivian–lowest Barremian, as opposed to the cyclical paleoenvironmental stability inferred for the early/late Valanginian–early Hauterivian, which would have prompted stasis inP. koeneniandP. esbelta.

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