scholarly journals Maintained larval growth in mussel larvae exposed to acidified under-saturated seawater

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Alexander Ventura ◽  
Sabrina Schulz ◽  
Sam Dupont
Keyword(s):  
Blue Mussel ◽  
Larval Mortality ◽  
Larval Growth ◽  
Energy Costs ◽  
Early Life Stages ◽  
Saturation State ◽  
Physiological Tolerance ◽  
Seawater Ph ◽  
Wide Range ◽  
Trochophore Stage

Abstract Ocean acidification (OA) is known to affect bivalve early life-stages. We tested responses of blue mussel larvae to a wide range of pH in order to identify their tolerance threshold. Our results confirmed that decreasing seawater pH and decreasing saturation state increases larval mortality rate and the percentage of abnormally developing larvae. Virtually no larvae reared at average pHT 7.16 were able to feed or reach the D-shell stage and their development appeared to be arrested at the trochophore stage. However larvae were capable of reaching the D-shell stage under milder acidification (pHT ≈ 7.35, 7.6, 7.85) including in under-saturated seawater with Ω a as low as 0.54 ± 0.01 (mean ± s. e. m.), with a tipping point for normal development identified at pHT 7.765. Additionally growth rate of normally developing larvae was not affected by lower pHT despite potential increased energy costs associated with compensatory calcification in response to increased shell dissolution. Overall, our results on OA impacts on mussel larvae suggest an average pHT of 7.16 is beyond their physiological tolerance threshold and indicate a shift in energy allocation towards growth in some individuals revealing potential OA resilience.

Effects of larval diet quality on the growth and development of immature stages of Telostylinus angusticollis (Diptera : Neriidae)

2018 ◽  
Vol 66 (6) ◽  
pp. 369
Author(s):  
Amy K. Hooper ◽  
Russell Bonduriansky
Keyword(s):  
Life History ◽  
Diet Quality ◽  
Nutrient Concentration ◽  
Larval Mortality ◽  
Larval Growth ◽  
Pupal Stage ◽  
Immature Stages ◽  
Larval Diet ◽  
Wide Range ◽  
Growth Development

Nutrient abundance during development has profound effects on adult morphology, life history and behaviour in many insects, but effects of nutrition on juvenile development are less well known. We investigated how larval diet quality affects patterns of growth, development and survival of larvae and pupae in the neriid fly Telostylinus angusticollis (Enderlein). We reared flies on two larval diets varying in nutrient concentration (‘rich’ versus ‘poor’) that have been shown previously to affect a wide range of adult traits in this species. We found that nutrient concentration affected larval growth trajectories, with individuals reared on the rich diet exhibiting greatly accelerated growth and reaching a larger body size. By contrast, we found no evidence that diet affected timing of development at the pupal stage, suggesting that developmental constraints may prevent variation in pupal development rate. Although overall mortality during the immature stages was not affected by larval diet, we found some evidence that individuals reared on a poor diet might experience higher larval mortality, whereas individuals reared on a rich diet might experience higher mortality during emergence from the puparium. Our results enhance understanding of the effects of nutrition on growth, development, and life history.

scholarly journals Not Only a Formulation: The Effects of Pickering Emulsion on the Entomopathogenic Action of Metarhizium brunneum

2021 ◽  
Vol 7 (7) ◽  
pp. 499
Author(s):  
Nitsan Birnbaum ◽  
Victoria Reingold ◽  
Sabina Matveev ◽  
Chandrasekhar Kottakota ◽  
Michael Davidovitz ◽  
...  
Keyword(s):  
Ricinus Communis ◽  
Larval Mortality ◽  
Acute Infection ◽  
Larval Growth ◽  
Disease Process ◽  
Pickering Emulsion ◽  
Broad Host Range ◽  
High Humidity ◽  
Conventional Agriculture ◽  
Metarhizium Brunneum

Growing global population and environmental concerns necessitate the transition from chemical to eco-friendly pest management. Entomopathogenic fungi (EPF) are rising candidates for this task due to their ease of growing, broad host range and unique disease process, allowing EPF to infect hosts directly through its cuticle. However, EPF’s requirement for high humidity negates their integration into conventional agriculture. To mitigate this problem, we formulated Metarhizium brunneum conidia in an oil-in-water Pickering emulsion. Conidia in aqueous and emulsion formulations were sprayed on Ricinus communis leaves, and Spodoptera littoralis larvae were introduced under low or high humidity. The following were examined: conidial dispersion on leaf, larval mortality, conidial acquisition by larvae, effects on larval growth and feeding, and dynamic of disease progression. Emulsion was found to disperse conidia more efficiently and caused two-fold more adhesion of conidia to host cuticle. Mortality from conidia in emulsion was significantly higher than other treatments reaching 86.5% under high humidity. Emulsion was also found to significantly reduce larval growth and feeding, while conferring faster fungal growth in-host. Results suggest that a Pickering emulsion is able to improve physical interactions between the conidia and their surroundings, while weakening the host through a plethora of mechanisms, increasing the chance of an acute infection.

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

scholarly journals SIMULATION OF CO2 AND H2S EXTRACTION PROCESSES FROM BIOGAS USING AMINE AND WATER ABSORPTION

2018 ◽  
pp. 11-22
Author(s):  
Yu.V. Ivanov ◽  
O.I. Pyatnychko ◽  
G.V. Zhuk ◽  
L.R. Onopa ◽  
S.P. Krushnevich ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Absorption ◽  
Heat Load ◽  
Biogas Production ◽  
Energy Costs ◽  
Software Modeling ◽  
Absorption Loss ◽  
Hydrogen Sulfide Removal ◽  
Wide Range ◽  
Extraction Processes

The research of technological circuits of biomethane from biogas production with the use of the most widespread amine and water absorption processes of carbon dioxide and hydrogen sulfide removal from biogas is carried out. With the use of software modeling for the amine process, an effective absorbent MDEAmod — an aqueous solution of methyldiethanolamine and monoethanolamine is proposed. This absorbent can be effectively applied to a wide range of biogas and for a range of pressure practically from atmospheric to 0.28 MPa. At the same time, the heat load of desorber reboiler is less in 1.5–4 times compared with the use of monoethanolamine solutions.Comparison of energy costs for the production of biomethane using amine and water technology shows that taking into account the greater yield of biomethane in the amine process by 8–15 % than in water absorption (loss of CH4 due to dissolution in H2O), and the use of this difference to heat the amine desorber reboiler these costs are comparative. In the case of the need to produce carbon dioxide as a commodity product, the amine process has an advantage, since the CO2 achieved in this process has a concentration of 98 % versus 80 % when using water absorption. The obtained results of simulation of СО2 and H2S removal process by amine and water absorption can be used in technologies of biogas refining and production of biomethane - an analogue of natural gas, as well as carbon dioxide as a commercial product. Bibl. 24, Fig. 6, Tab. 4.

scholarly journals Conjugated linoleic acid as a novel insecticide targeting the agricultural pest Leptinotarsa decemlineata

2019 ◽  
Author(s):  
Justin Clements ◽  
Russell L. Groves ◽  
JoAnn Cava ◽  
Caroline Barry ◽  
Scott Chapman ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Larval Mortality ◽  
Larval Growth ◽  
The United States ◽  
Feeding Preference ◽  
Agricultural Pest ◽  
Potato Beetle

AbstractThe Colorado Potato Beetle, Leptinotarsa decemlineata, is a major agricultural pest of solanaceous crops in the United States. Historically, a multitude of insecticides have been used to control problematic populations. Due to increasing resistance to insecticides, novel compounds and methodologies are warranted for the control of beetle populations. Mixed-isomer conjugated linoleic acid has been studied in-depth for its beneficial properties to mammalian systems. At the same time, studies have demonstrated that conjugated linoleic acid can manipulate fatty acid composition in non-mammalian systems, resulting in embryo mortality. Consequently, experiments were conducted to assess the effects of foliar-applied conjugated linoleic acid on larval growth, embryogenesis, and feeding preference in Colorado potato beetle. Both maternal and deterrent effects of dietary conjugated linoleic acid were assessed. Conjugated linoleic acid demonstrated desirable insecticidal properties, including increased larval mortality, slowed larval development, antifeedant effects, and decreased egg viability after maternal ingestion.

scholarly journals Scaling of cytoskeletal organization with cell size in Drosophila

2017 ◽  
Vol 28 (11) ◽  
pp. 1519-1529 ◽  
Author(s):  
Alison K. Spencer ◽  
Andrew J. Schaumberg ◽  
Jennifer A. Zallen
Keyword(s):  
Cell Size ◽  
Quantitative Imaging ◽  
Larval Growth ◽  
Fold Increase ◽  
Ventral Surface ◽  
Tissue Growth ◽  
Cell Length ◽  
Drosophila Embryo ◽  
Microtubule Network ◽  
Wide Range

Spatially organized macromolecular complexes are essential for cell and tissue function, but the mechanisms that organize micron-scale structures within cells are not well understood. Microtubule-based structures such as mitotic spindles scale with cell size, but less is known about the scaling of actin structures within cells. Actin-rich denticle precursors cover the ventral surface of the Drosophila embryo and larva and provide templates for cuticular structures involved in larval locomotion. Using quantitative imaging and statistical modeling, we demonstrate that denticle number and spacing scale with cell length over a wide range of cell sizes in embryos and larvae. Denticle number and spacing are reduced under space-limited conditions, and both features robustly scale over a 10-fold increase in cell length during larval growth. We show that the relationship between cell length and denticle spacing can be recapitulated by specific mathematical equations in embryos and larvae and that accurate denticle spacing requires an intact microtubule network and the microtubule minus end–binding protein, Patronin. These results identify a novel mechanism of micro­tubule-dependent actin scaling that maintains precise patterns of actin organization during tissue growth.

RNAi-Mediated Screening of Selected Target Genes Against Culex quinquefasciatus (Diptera: Culicidae)

2021 ◽  
Author(s):  
Sayed M S Khalil ◽  
Kashif Munawar ◽  
Azzam M Alahmed ◽  
Ahmed M A Mohammed
Keyword(s):  
Culex Quinquefasciatus ◽  
Target Genes ◽  
Mosquito Control ◽  
Larval Mortality ◽  
Adult Emergence ◽  
Lethal Effect ◽  
Delivery Methods ◽  
Valley Fever ◽  
Wide Range ◽  
Lethal Genes

Abstract Culex quinquefasciatus, a member of the Culex pipiens complex, is widespread in Saudi Arabia and other parts of the world. It is a vector for lymphatic filariasis, Rift Valley fever, and West Nile virus. Studies have shown the deleterious effect of RNA interference (RNAi)-mediated knockdown of various lethal genes in model and agricultural pest insects. RNAi was proposed as a tool for mosquito control with a focus on Aedes aegypti and Anopheles gambiae. In this study, we examined the effect of RNAi of selected target genes on both larval mortality and adult emergence of Cx. quinquefasciatus through two delivery methods: soaking and nanoparticles. Ten candidate genes were selected for RNAi based on their known lethal effect in other insects. Disruption of three genes, chitin synthase-1, inhibitor of apoptosis 1, and vacuolar adenosine triphosphatase, resulted in the highest mortality among the selected genes using the two treatment methods. Silencing the other seven genes resulted in a medium to low mortality in both assays. These three genes are also active against a wide range of insects and could be used for RNAi-based mosquito control in the future.

scholarly journals Black Soldier Fly Larvae Adapt to Different Food Substrates through Morphological and Functional Responses of the Midgut

2020 ◽  
Vol 21 (14) ◽  
pp. 4955
Author(s):  
Marco Bonelli ◽  
Daniele Bruno ◽  
Matteo Brilli ◽  
Novella Gianfranceschi ◽  
Ling Tian ◽  
...  
Keyword(s):  
Larval Growth ◽  
Nutrient Content ◽  
Functional Responses ◽  
Black Soldier Fly ◽  
Poor Diet ◽  
Balanced Diet ◽  
Long Term Storage ◽  
Wide Range ◽  
Extreme Variability ◽  
Adaptation Processes

Modulation of nutrient digestion and absorption is one of the post-ingestion mechanisms that guarantees the best exploitation of food resources, even when they are nutritionally poor or unbalanced, and plays a pivotal role in generalist feeders, which experience an extreme variability in diet composition. Among insects, the larvae of black soldier fly (BSF), Hermetia illucens, can grow on a wide range of feeding substrates with different nutrient content, suggesting that they can set in motion post-ingestion processes to match their nutritional requirements. In the present study we address this issue by investigating how the BSF larval midgut adapts to diets with different nutrient content. Two rearing substrates were compared: a nutritionally balanced diet for dipteran larvae and a nutritionally poor diet that mimics fruit and vegetable waste. Our data show that larval growth performance is only moderately affected by the nutritionally poor diet, while differences in the activity of digestive enzymes, midgut cell morphology, and accumulation of long-term storage molecules can be observed, indicating that diet-dependent adaptation processes in the midgut ensure the exploitation of poor substrates. Midgut transcriptome analysis of larvae reared on the two substrates showed that genes with important functions in digestion and absorption are differentially expressed, confirming the adaptability of this organ.

Laboratory culture of Dreissena polymorpha larvae: spawning success, adult fecundity, and larval mortality patterns

2004 ◽  
Vol 82 (9) ◽  
pp. 1436-1443 ◽  
Author(s):  
James A Stoeckel ◽  
Dianna K Padilla ◽  
Daniel W Schneider ◽  
Chris R Rehmann
Keyword(s):  
Life History ◽  
Dreissena Polymorpha ◽  
Egg Production ◽  
Larval Mortality ◽  
Field Studies ◽  
Laboratory Culture ◽  
Minimum Size ◽  
Critical Periods ◽  
Brood Stock ◽  
Wide Range

Understanding the entire life history, especially critical periods during the life cycle of a species, is important for understanding population dynamics and is crucial for control of nuisance species. Errors in estimates of growth rates and recruitment in field and modeling studies are likely to occur if one assumes uniform rather than size- or stage-specific mortalities for larval stages. Similarly, effects of brood-stock health on adult fecundity and larval mortality patterns might affect results of laboratory studies investigating larval life history. We maintained zebra mussels, Dreissena polymorpha (Pallas, 1771), in spawning condition in the laboratory for 24 weeks. Healthy larvae were produced for 18 weeks. However, induction of spawning and egg production declined through time. Fecundity increased with size per female, but sperm production did not for males. We found no correlation between clutch size and egg size across a wide range of clutch sizes. Survivorship was greater when larvae were reared at lower densities. Daily larval mortality was strongly size dependent; the average size of dead larvae was similar to the minimum size of live larvae. Highest daily larval mortality occurred during the transition from D stage to umbonal stage, supporting the suggestion of a developmental bottleneck as found in previous field studies.

Mortality Variations in Natural Populations of the Blue Mussel, Mytilus edulis

1987 ◽  
Vol 44 (9) ◽  
pp. 1589-1594 ◽  
Author(s):  
A. L. Mallet ◽  
C. E. A. Carver ◽  
S. S. Coffen ◽  
K. R. Freeman
Keyword(s):  
Mytilus Edulis ◽  
Environmental Gradient ◽  
Blue Mussel ◽  
Natural Populations ◽  
Seasonal Patterns ◽  
Cumulative Mortality ◽  
Variable Environments ◽  
Wide Range ◽  
Stressful Environments ◽  
Physiological Flexibility

To investigate environmental and seasonal patterns of mortality among natural populations of the blue mussel, Mytilus edulis, we transplanted 11 stocks of juvenile mussels to nine sites along the coast of Nova Scotia, Canada. Stock, Stock by Site, and Stock by Season together accounted for 53% of the variance in mortality whereas Site and Season together explained less than 1% of the variance. Genetic variability among stocks was inferred from differences in their cumulative mortality averaged over all environments. Several stocks, however, exhibited similar levels of mortality over all sites and were apparently insensitive to the environmental gradient. This implies physiological flexibility or the ability to tolerate a wide range of environmental conditions. We conclude that the blue mussel adapts to variable environments by maintaining both physiologically flexible and genetically variable populations. In addition, we noted that stocks originating from more stressful environments tended to exhibit lower mortalities than those originating from less stressful environments.

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