Effect of larval density and algal concentration on growth, survival and feeding rates of the scallop Nodipecten subnodosus (Sowerby, 1835)

2021 ◽  
Author(s):  
Marco A. Angel‐Dapa ◽  
Gabriel E. Nava‐Gómez ◽  
Laura López‐Galindo ◽  
Eugenio Carpizo‐Ituarte ◽  
Sheila Castellanos‐Martínez ◽  
...  
Keyword(s):  
Larval Density ◽  
Feeding Rates ◽  
Algal Concentration

scholarly journals Evolution of increased larval competitive ability in Drosophila melanogaster without increased larval feeding rate

2015 ◽  
Author(s):  
Manaswini Sarangi ◽  
Archana Nagarajan ◽  
Snigdhadip Dey ◽  
Joy Bose ◽  
Amitabh Joshi
Keyword(s):  
Competitive Ability ◽  
Unit Volume ◽  
Larval Density ◽  
Larval Feeding ◽  
Food Conversion ◽  
Feeding Rates ◽  
Laboratory Populations ◽  
Larval Crowding ◽  
The Cost

Multiple experimental evolution studies on D. melanogaster in the 1980s and 1990s indicated that enhanced competitive ability evolved primarily through increased larval tolerance to nitrogenous wastes and increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and this became the widely accepted view of how adaptation to larval crowding evolves in fruitflies. We recently showed that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolved greater competitive ability without evolving higher feeding rates, primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater efficiency of food conversion to biomass, increased pupation height and, perhaps, greater urea/ammonia tolerance. This was a very different suite of traits than that seen to evolve under similar selection in D. melanogaster and was closer to the expectations from the theory of K-selection. At that time, we suggested two possible reasons for the differences in the phenotypic correlates of greater competitive ability seen in the studies with D. melanogaster and the other two species. First, that D. ananassae and D. n. nasuta had a very different genetic architecture of traits affecting competitive ability compared to the long-term, laboratory populations of D. melanogaster used in the earlier studies, either because the populations of the former two species were relatively recently wild-caught, or by virtue of being different species. Second, that the different evolutionary trajectories in D. ananassae and D. n. nasuta versus D. melanogaster were a reflection of differences in the manner in which larval crowding was imposed in the two sets of selection experiments. The D. melanogaster studies used a higher absolute density of eggs per unit volume of food, and a substantially larger total volume of food, than the studies on D. ananassae and D. n. nasuta. Here, we show that long-term laboratory populations of D. melanogaster, descended from some of the populations used in the earlier studies, evolve essentially the same set of traits as the D. ananassae and D. n. nasuta crowding-adapted populations when subjected to a similar larval density at low absolute volumes of food. As in the case of D. ananassae and D. n. nasuta, and in stark contrast to earlier studies with D. melanogaster, these crowding-adapted populations of D. melanogaster did not evolve greater larval feeding rates as a correlate of increased competitive ability. The present results clearly suggest that the suite of phenotypes through which the evolution of greater competitive ability is achieved in fruitflies depends critically not just on larval density per unit volume of food, but also on the total amount of food available in the culture vials. We discuss these results in the context of an hypothesis about how larval density and the height of the food column in culture vials might interact to alter the fitness costs and benefits of increased larval feeding rates, thus resulting in different routes to the evolution of greater competitive ability, depending on the details of exactly how the larval crowding was implemented.

scholarly journals Comparative Efficacy of Pimephales promelas, Fundulus diaphanus, and Gambusia affinis and Influence of Prey Density for Biological Control of Culex pipiens molestus Larvae

2018 ◽  
Vol 34 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Matthew W. Bickerton ◽  
Joseph Corleto ◽  
Thomas N. Verna ◽  
Eric Williges ◽  
Deepak Matadha
Keyword(s):  
Fish Species ◽  
Culex Pipiens ◽  
Prey Density ◽  
Larval Density ◽  
Pimephales Promelas ◽  
Gambusia Affinis ◽  
Feeding Rates ◽  
Survival Times ◽  
Culex Pipiens Molestus ◽  
Fundulus Diaphanus

ABSTRACT Larval survival times and density-dependent feeding behavior were evaluated with the use of 2 species of fish native to the northeastern USA (Pimephales promelas and Fundulus diaphanus), and the potentially invasive Gambusia affinis. Each species was provided 10, 20, 30, 45, and 60 4th-stage larvae of Culex pipiens molestus/fish in the laboratory and digital images were recorded to quantify the number of surviving larvae at various intervals. Daily feeding rates were greatest at the highest larval density. These were 49.69 ± 4.07 larvae for P. promelas, 60 larvae for F. diaphanus, and 36.44 ± 6.6 larvae for G. affinis. Survival analysis was used to compare efficacy of each fish species over time. All fish species consumed larvae at similar rates at lower densities, but significant differences occurred at densities of 30–60 larvae/fish. Survival times of larvae at the highest density were 44 ± 7.9 h for P. promelas, 15 ± 3.4 h for F. diaphanus, and 70.6 ±13 h for G. affinis. In order to evaluate feeding rate as a function of prey density, we compared consumption rates 1.5 h after feeding with the use of a 4-parameter logistic model. Fundulus diaphanus and G. affinis feeding aligned with the 4-parameter model, indicating that initial feeding rates for these species increased with prey density to an upper limit (satiation). Pimephales promelas feeding within 1.5 h did not align with this model, suggesting that early feeding rates for this species are not heavily influenced by prey density.

A method for rearing Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) larvae on a modified artificial diet

2015 ◽  
Vol 68 ◽  
pp. 353-359 ◽  
Author(s):  
A.M. Barrington ◽  
D.P. Logan ◽  
P.G. Connolly
Keyword(s):  
Introduced Species ◽  
Artificial Diet ◽  
Larval Density ◽  
Pine Bark ◽  
Pine Wood ◽  
Rearing Method ◽  
Sawn Timber

Burnt pine longhorn (BPL) Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) is an introduced species sometimes found in association with export logs and sawn timber A rearing method was developed to produce larvae of a known age number and quality for control trials Growth of larvae from newly hatched to 5 weeks was measured on a standard cerambycid artificial diet and on modified diets Replacing pine wood with pine bark sawdust increased survival at 5 weeks from 23 to 76 and mean weight from 9 to 21 mg There were significant interactions between the influences of three factors (diet period of rearing initial larval density) on the weight of surviving larvae Individual rearing was preferred for convenience and a standardised method was used to rear 8740 larvae for disinfestation trials Establishment and survival to 6 weeks for these larvae was 97

A treatability index for reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 27-33 ◽  
Author(s):  
C. T. Ta ◽  
C. A. Woodward
Keyword(s):  
Water Treatment ◽  
Filtration Rate ◽  
Water Area ◽  
Reservoir Water ◽  
Algal Concentration ◽  
Run Lengths ◽  
Water Treatments

A Treatability Index is developed to allow comparison of different reservoir waters according to their effects on a water treatments works. For the water treatment works which employs rapid gravity filters, the index is the product of the algal concentration, the clarification coefficients of algae and the filtration rate. The index is applied to reservoir waters within Thames Water area. Algae observed in reservoirs are grouped according to their shapes. Among these groups, twenty frequently observed species were selected and their clarification coefficients were measured. The treatability index was then evaluated for different waters and at different times of the year. The results were correlated to the filter run lengths and the development of headloss across the filters.

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