Enhanced gut fullness and an apparent shift in size selectivity by radiated shanny (Ulvaria subbifurcata) larvae in response to increased turbulence

1998 ◽  
Vol 55 (1) ◽  
pp. 128-142 ◽  
Author(s):  
John F Dower ◽  
Pierre Pepin ◽  
William C Leggett
Keyword(s):  
Turbulent Velocity ◽  
Larval Feeding ◽  
Large Prey ◽  
Feeding Rates ◽  
Size Selectivity ◽  
Prey Concentration ◽  
Feeding Success ◽  
High Turbulence ◽  
Apparent Shift ◽  
The Relationship

We studied the relationship between microscale turbulence and feeding success of larval radiated shanny (Ulvaria subbifurcata) in Conception Bay, Newfoundland, during a 3-week period in July-August 1995. Although previous studies had suggested that the relationship between turbulent velocity and larval feeding rates should be dome shaped, we found no evidence of such a functional relationship. Rather, differences in larval feeding success were evident only when days were grouped as either "high turbulence" or "low turbulence" on the basis of Richardson number. Feeding conditions (i.e., prey concentration and composition) were not significantly different on high- versus low-turbulence days. Nonetheless, U. subbifurcata larvae (3-14 mm standard length) contained significantly fewer items in their guts on high-turbulence days. These prey items, however, were (on average) significantly larger than those found in guts on low-turbulence days; the net result was that significantly greater volumes of food were found in larval guts on high-turbulence days. Turbulent velocity did not affect between-day variation in RNA:DNA ratios of the larvae. We suggest that what appears to be a shift in size selectivity by U. subbifurcata larvae under increased turbulence may result from larvae having a higher probability of capturing large prey under increasingly turbulent conditions.

scholarly journals Suction feeding performance and prey escape response interact to determine feeding success in larval fish

2019 ◽  
Author(s):  
Noam Sommerfeld ◽  
Roi Holzman
Keyword(s):  
Early Development ◽  
Escape Response ◽  
High Speed ◽  
Sparus Aurata ◽  
Larval Fish ◽  
Reynolds Numbers ◽  
Larval Performance ◽  
Larval Feeding ◽  
Large Prey ◽  
Feeding Success

AbstractThe survival of larval marine fishes during early development is strongly dependent on their ability to capture prey. Most larval fish capture prey by expanding their mouth cavity, generating a “suction flow” that draws the prey into their mouth. Larval fish dwell in a hydrodynamic regime of low Reynolds numbers, which has been shown to impede their ability to capture non-evasive prey. However, the marine environment is characterized by an abundance of evasive prey such as Copepods. These organisms can sense the hydrodynamic disturbance created by approaching predators and perform high-acceleration escape maneuvers. Using a 3D high-speed video system, we characterized the interaction between 8-33 day post hatchingSparus auratalarvae and prey from a natural zooplankton assemblage that contained evasive prey, and assessed the factors that determine the outcome of these interactions. Larvae showed strong selectivity for large prey that was moving prior to the initialization of the strike. As previously shown in studies with non-evasive prey, larval feeding success increased with increasing Reynolds numbers. However, larval feeding success was also strongly dependent on the prey’s escape response. Feeding success was lower for larger, more evasive prey, indicating that larvae might be challenged in capturing their preferred prey. The kinematics of successful strikes resulted in shorter response time but higher hydrodynamic signature available for the prey. Thus, despite being “noisier”, successful strikes on evasive prey depended on preceding the prey’s escape response. Our results show that larval performance, rather than larval preferences, determines their diet during early development.

A Conceptual Model for the Estimation of the Sensitivity of Black Fly Larvae to Bacillus thuringiensis var. israelensis

1989 ◽  
Vol 46 (10) ◽  
pp. 1785-1792 ◽  
Author(s):  
Antoine Morin ◽  
Christian Back ◽  
Jacques Boisvert ◽  
Robert H. Peters
Keyword(s):  
Bacillus Thuringiensis ◽  
Feeding Rate ◽  
Standard Procedure ◽  
Dry Mass ◽  
Published Data ◽  
Contact Period ◽  
Larval Feeding ◽  
Feeding Rates ◽  
Black Fly ◽  
Proposed Model

Results from bioassays of a commercial formulation of Bacillus thuringiensis var. israelensis (Teknar HP-D) are combined with an empirical model of the feeding rate of larvae of a target species of black fly (Simulium venustum/verecundum) to develop a model relating the mortality of larvae to the amount of formulation ingested per unit mass of larvae (specific ingested dose). LD50 of Teknar HP-D was about 1 μg wet mass of Teknar per milligram dry mass of larvae, and independent of size of the larvae and seston concentration. Compared with standard assay analysis relating the mortality to the dose (milligrams per litre times seconds), the proposed model allowed more precise and replicable estimation of the effective dose. Reanalysis of published data on the potency of another Bti formulation (Teknar WDC), confirmed the superiority of the proposed model over the standard procedure. Susceptibility of larvae to particulate larvicides is mainly a function of the larval feeding rate. In addition to size of the larvae, temperature, and seston concentration, analysis of the model reveals that the length of the contact period and the variability of feeding rates among individual larvae are important factors determining the mortality rate following treatments.

scholarly journals Hydrodynamic regime determines the feeding success of larval fish through the modulation of strike kinematics

2017 ◽  
Vol 284 (1853) ◽  
pp. 20170235 ◽  
Author(s):  
Victor China ◽  
Liraz Levy ◽  
Alex Liberzon ◽  
Tal Elmaliach ◽  
Roi Holzman
Keyword(s):  
High Speed ◽  
Sparus Aurata ◽  
Larval Fish ◽  
Reynolds Numbers ◽  
Early Ontogeny ◽  
Hydrodynamic Regime ◽  
Physical Growth ◽  
Larval Feeding ◽  
Feeding Success ◽  
Order Of Magnitude

Larval fishes experience extreme mortality rates, with 99% of a cohort perishing within days after starting to actively feed. While recent evidence suggests that hydrodynamic factors contribute to constraining larval feeding during early ontogeny, feeding is a complex process that involves numerous interacting behavioural and biomechanical components. How these components change throughout ontogeny and how they contribute to feeding remain unclear. Using 339 observations of larval feeding attempts, we quantified the effects of morphological and behavioural traits on feeding success of Sparus aurata larvae during early ontogeny. Feeding success was determined using high-speed videography, under both natural and increased water viscosity treatments. Successful strikes were characterized by Reynolds numbers that were an order of magnitude higher than those of failed strikes. The pattern of increasing strike success with increasing age was driven by the ontogeny of traits that facilitate the transition to higher Reynolds numbers. Hence, the physical growth of a larva plays an important role in its transition to a hydrodynamic regime of higher Reynolds numbers, in which suction feeding is more effective.

scholarly journals Once upon a larva: revisiting the relationship between feeding success and growth in fish larvae

2014 ◽  
Vol 72 (2) ◽  
pp. 359-373 ◽  
Author(s):  
Pierre Pepin ◽  
Dominique Robert ◽  
Caroline Bouchard ◽  
John F. Dower ◽  
Marianne Falardeau ◽  
...  
Keyword(s):  
Growth Rates ◽  
Larval Fish ◽  
Fish Larvae ◽  
Fish Growth ◽  
Individual Growth ◽  
Growth Time ◽  
Feeding Rates ◽  
Average Growth ◽  
Fast Growing ◽  
Feeding Success

Abstract Variations in larval fish growth rates are largely the result of variability in biotic and abiotic characteristics of the feeding environment experienced by each individual. An assessment of an individual's overall feeding success (i.e. accumulation of utilizable organic matter) can best be achieved at the time of capture when the relationships among environment, short-term feeding success as defined by gut content and long-term feeding success as defined by accumulated growth can be contrasted. Here, we investigated the relationships between average growth, feeding success, and variability in individual growth and feeding rates across a range of taxa based on a synthesis of studies in which stomach content and otolith growth were measured in the same individuals. Instantaneous measures of feeding success were highly variable and demonstrated a positive yet somewhat limited association with growth rates across all taxa. The strength of the feeding-growth relationships among taxa, and cohorts within taxa, was reflected in the autocorrelation of individual growth rates, suggesting that stable growth was achieved through consistent feeding success. However, when viewed at the individual level, faster growth was achieved in individuals with more variable growth rates, and by inference more variable past feeding success. The dichotomy in these underlying relationships may point to the importance of stochastic events in the development of exceptional individuals in a population, and may be linked to how surplus energy is allocated to individual growth rates. The positive correlation found between feeding success and growth in all taxa is consistent with the growth-survival paradigm for the larval stage of fish. However, both the correlation between feeding success and growth and the serial correlation of growth time-series was greatest in fast-growing species, suggesting that the potential for an early “critical period” regulating survival varies among species, reaching a maximum in fast-growing fish.

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.

Swimming ants and pitcher plants: a unique ant-plant interaction from Borneo

1995 ◽  
Vol 11 (4) ◽  
pp. 589-602 ◽  
Author(s):  
C. M. Clarke ◽  
R. L. Kitching
Keyword(s):  
Digestive System ◽  
Mosquito Larvae ◽  
Large Prey ◽  
Pitcher Plant ◽  
Small Prey ◽  
Plant Interaction ◽  
Nesting Sites ◽  
Mutualistic Association ◽  
The Relationship ◽  
Prey Items

ABSTRACTThe relationship between Camponotus sp. ants and the carnivorous pitcher plant, Nepenthes bicalcarata, from Borneo were investigated. The ants nest in the hollow tendrils of the plant, and feed on large prey items caught by the pitchers. These are hauled from the pitcher fluid by the ants and consumed. When large prey items are absent, the ants feed upon mosquito larvae which inhabit the pitcher fluid. The accumulation of excess prey in pitchers can lead to putrefaction of the contents, and disruption of the pitcher's digestive system. Experiments on the possible benefits of the ants' behaviour to the plant showed that the accumulation of excess prey and the putrefaction of the pitcher contents were significantly reduced in the presence of the ants. The accumulation of ammonia in pitchers was unaffected by the presence of the ants when small prey were added to pitchers, but was reduced significantly in the presence of ants when large prey were added. It is suggested that Camponotus sp. and N. bicalcarata have a mutualistic association, from which the ants obtain food and nesting sites and, in return, prevent damaging accumulation of excess prey in the pitchers.

Nestling feeding rates and body size of adult House Sparrows

1984 ◽  
Vol 62 (3) ◽  
pp. 381-385 ◽  
Author(s):  
W. Bruce McGillivray
Keyword(s):  
Body Size ◽  
Feeding Rate ◽  
Passer Domesticus ◽  
The Body ◽  
Feeding Rates ◽  
House Sparrows ◽  
Relative Contribution ◽  
Nestling Feeding ◽  
The Relationship

Much of the variance in feeding rates of nestlings by adult House Sparrows (Passer domesticus) at Calgary, Alberta appears to be due to individual variation in the quality of the parents. Males contribute less to nestling feeding than do males at other localities. The body size and sexual size dimorphism of House Sparrows has been shown to increase with increasing latitude in North America. Hence, sparrows at Calgary are larger than average and there is a suggestion that the relative contribution by the sexes is related to male size and concomitant energetic limitations. The relationship between weight and body size is strong in the fall for both male and female House Sparrows but is poor during the breeding season. Adult females, but not males, increase their nestling feeding rate in inclement weather.

Growth and early sexual maturation in Baltic salmon (Salmo salar) parr

1992 ◽  
Vol 70 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Ingemar Berglund
Keyword(s):  
Growth Rate ◽  
Salmo Salar ◽  
Sexual Maturation ◽  
Specific Growth ◽  
Gonadal Development ◽  
Feeding Rates ◽  
Gonadal Growth ◽  
Hatchery Stock ◽  
Size At Age ◽  
The Relationship

The relationship between sexual maturation and growth in Baltic salmon (Salmo salar) parr was studied in hatchery stock originating from the Umeälven (Ume River) in northern Sweden. The probability that a male parr would mature sexually at age 1 + was positively related to its size at the start of the experiment at age 0+. The specific growth rate and condition factor of maturing and nonmaturing males were similar until the onset of gonadal growth, when the growth rate of maturing males decreased. Sibling groups of immature parr were fed different rations during the 3 weeks prior to the start of gonadal development. The incidence of sexual maturation in the groups given different rations was linearly related to the growth rate during the period of different feeding rates. This study suggests that both the size at age 1, resulting from the growth rate during the first summer, and the opportunity for growth during the period preceding the onset of gonadal growth affect the incidence of maturation in male parr of age 1 +.

Effects of Light and Turbidity on the Reactive Distance of Bluegill (Lepomis macrochirus)

1976 ◽  
Vol 33 (12) ◽  
pp. 2845-2849 ◽  
Author(s):  
Gary L. Vinyard ◽  
W. John O’brien
Keyword(s):  
Lepomis Macrochirus ◽  
Substantial Reduction ◽  
Daphnia Pulex ◽  
Large Prey ◽  
Feeding Rates ◽  
Fish Feeding ◽  
Turbid Waters ◽  
Reactive Distance ◽  
Light Intensities

Changes in the reactive distance of bluegill (Lepomis macrochirus) to various sizes of Daphnia pulex were measured at light intensities ranging from 0.70 to 215.3 lx (0.065–20.0 ft-c) and at turbidities ranging from 1 to 30 Jackson Turbidity Units (JTU). Both reduced illumination and increased turbidity caused substantial reduction in the reactive distance of bluegill for all prey sizes, and particularly for large prey. This result should be considered in efforts to determine fish feeding rates in lakes, and may be particularly relevant to vertically migrating zooplankton, or those inhabiting more turbid waters.

Sign in / Sign up

Export Citation Format

Share Document