Competition for perches between larval damselflies: the influence of perch use on feeding efficiency, growth rate and predator avoidance

1988 ◽  
Vol 19 (1) ◽  
pp. 15-28 ◽  
Author(s):  
PETER CONVEY
Keyword(s):  
Growth Rate ◽  
Predator Avoidance ◽  
Feeding Efficiency

Larval growth in three sympatric Ambystoma salamander species: species differences and the effects of temperature

1984 ◽  
Vol 62 (6) ◽  
pp. 1043-1047 ◽  
Author(s):  
W. Hubert Keen ◽  
Joseph Travis ◽  
John Juilianna
Keyword(s):  
Growth Rate ◽  
Predator Avoidance ◽  
Species Differences ◽  
Larval Growth ◽  
Ambystoma Tigrinum ◽  
Close Proximity ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Behavioral Mechanisms ◽  
Salamander Species

Differences in the larval growth of three Ambystoma salamander species that breed in close proximity to each other in space and time in north Florida were investigated under standardized regimes of controlled food levels and temperature. The order of species growth rates was as follows: Ambystoma tigrinum > A. talpoideum > A. opacum. This order is exactly the reverse of the order in which the species breed. Growth of A. talpoideum larvae was strongly dependent on temperature, whereas A. opacum larval growth was only weakly affected by temperature. Based on these growth rate differences, it is unlikely that A. talpoideum larvae could survive to metamorphosis without special behavioral mechanisms for predator avoidance in habitats with the rapidly growing predatory A. tigrinum larvae. Furthermore, A. opacum larvae would be favored in their growth over those of A. talpoideum at low temperature, while the reverse would be true at higher temperature.

Anchors and snorkels: heterochrony, development and form in functionally constrained fossil crassatellid bivalves

Paleobiology ◽  
2016 ◽  
Vol 42 (2) ◽  
pp. 305-316 ◽  
Author(s):  
Katie S. Collins ◽  
James S. Crampton ◽  
Helen L. Neil ◽  
Euan G. C. Smith ◽  
Michael F. Gazley ◽  
...  
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
Morphological Change ◽  
Predator Avoidance ◽  
Morphological Variability ◽  
Developmental Timing ◽  
Environmental Pressure ◽  
Life Habit ◽  
Infaunal Bivalve ◽  
Key Drivers

AbstractNew growth rate estimates for nine species from three genera of New Zealand Crassatellidae (Mollusca: Bivalvia), combined with existing morphometric ontogenetic descriptions, allow identification of heterochronic processes in the evolution of these genera. Both paedomorphosis (progenesis and neoteny) and peramorphosis (hypermorphosis and acceleration) have occurred within the clade. Overall, morphological variability and response to environmental pressure in this nonsiphonate group is restricted by the interplay of anatomical and life habit constraints. Stability in the substrate, predator avoidance, sluggish burrowing speed, and inability to escape by deep burial are suggested as key drivers of, or constraints on, morphological change. Two groups of shell characters are identified: heavy, armored “anchors” and elongate “snorkels,” which combine juvenile and adult traits in shells of different sizes and ages, produced by heterochronic variation in developmental timing. Anchors and snorkels both represent different “solutions” to the problems of life as a nonsiphonate, infaunal bivalve.

scholarly journals Rearing of Milkfish, Chanos Chanos, in Net Cages at Sea at Various Stocking Densities

2007 ◽  
Vol 1 (2) ◽  
pp. 53
Author(s):  
Kusman Sumawidjaja ◽  
T. Yusdiana ◽  
Irzal Effendi ◽  
, Dharmadi
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Key Words ◽  
Stocking Density ◽  
Stocking Rate ◽  
Chanos Chanos ◽  
Feeding Efficiency ◽  
Final Length ◽  
Net Cage ◽  
Net Cages

<p>ABSTRACT</p><p>Stocking rate of milkfish, <em>Chanos chanos</em>, from 75 to 225 fish/m<sup>3 </sup> or from 1,33 to 3,98 kg/m<sup>3 </sup> did not affect the growth rate, survival rate, feeding efficiency, and final length and weight of fish, each at 2,32%/day, 81,8%, 63,8%, and 185,2 mm and 64,0 g respectively. Final biomass (Y) increased from 3,66 to 12,05 kg/m<sup>3</sup> with the increase of stocking rate (X) with Y = 0,056 X-0,45 (p&lt;0,05).</p><p>Key words :   Milkfish<em>, Chanos chanos</em>, floating net cage, stocking density.</p><p> </p><p>ABSTRAK</p><p>Padat penebaran ikan bandeng, <em>Chanos chanos</em>, dari 75 hingga 225 ekor/m<sup>3</sup> atau dari 1,33 hingga 3,98 kg/m<sup>3</sup> tidak mempengaruhi laju pertumbuhan, kelangsungan hidup, efisiensi pemberian pakan serta panjang dan bobot ikan akhir, masing-masing dengan rata-rata 2,32%/hari, 81,8%, 63,8%, 185,2 mm dan 64,0 g. Biomasa akhir (Y) meningkat dari 3,66 hingga 12,05 kg/m<sup>3</sup> dengan meningkatnya padat penebaran (X) dengan persamaan Y = 0,056 X -0,45 (p&lt;0,05).</p><p>Kata kunci :  Ikan bandeng, <em>Chanos chanos</em>, keramba jaring apung, padat penebaran</p>

scholarly journals Feeding with Artificial Feed on Sand Goby, Oxyeleotris marmorata (Blkr.), Fry

2007 ◽  
Vol 1 (3) ◽  
pp. 109
Author(s):  
Agus Oman Sudrajat ◽  
Irzal Effendi
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Dry Weight ◽  
Font Size ◽  
Sand Goby ◽  
Growth And Survival ◽  
Protein Retention ◽  
Feeding Efficiency ◽  
Two Factors ◽  
Time Of Feeding

<p class="MsoNormal" style="text-align: justify;"><span style="font-size: 11pt;" lang="in" xml:lang="in">ABSTRACT<br /></span></p><p class="MsoNormal" style="text-align: justify;"><span style="font-size: 11pt;" lang="in" xml:lang="in">The influence of feed shape and protein resource of artificial feed on the growth and survival rate of sand goby<em>, Oxyeleotris marmorata</em> (Blkr.), fry were evaluated in this experiment. This experiment purposed to determine growth rate, survival rate, feeding efficiency, protein retention, lypid retention and look for the suitable artificial feed for sand goby. This experiment was carried out at the Laboratory of Aquaculture System and Technology, Department of Aquaculture, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University in Bogor. Factorial design was used in this experiment with two factors: feed shape and protein resource. There were two kinds of feed shape: dry pellet and moist pellet. Protein resource consisted: fish, squid, and shrimp. The sand goby juveniles were kept in aquarium 60x30x40 cm was filled 40 litre of aerated. The fish were fed of 7% (dry weight based) of body weight in three time of feeding (10:00, 14:00, 18:00 WIB), 30, 30, 40% total feed/day respectively. The amount of feed was adjusted every 7 days with sampling. The juveniles feeding with shrimp-moist showed better survival rate, growth rate, feeding efficiency, protein retention, lypid retention than those fed shrimp-dry, squid-dry, squid-moist, fish-dry, and fish-moist. Dry pellet and moist pellet can be used for sand goby feeding. The artificial feed for sand goby juvenile suggested contain attractant and had highly water stability. Shrimp and squid can be used as main protein resources in artificial feed for sand goby. </span></p><p class="MsoBodyText2" style="margin-bottom: .0001pt;"><span style="font-size: 11pt;" lang="in" xml:lang="in">Key Word :<span>  </span>Feeding, artificial feed, sand goby, <em>Oxyeleotris<span>  </span>marmorata</em>, fry.</span></p><p class="MsoNormal"><span style="font-size: 11pt;" lang="in" xml:lang="in"> </span></p><h4 style="margin-top: 0cm; text-align: center;"><span style="font-size: 11pt;" lang="in" xml:lang="in">ABSTRAK</span></h4><p class="MsoNormal" style="text-align: justify;"><span style="font-size: 11pt;" lang="in" xml:lang="in">Penelitian ini bertujuan untuk mengetahui pengaruh bentuk pakan dan sumber protein dari pakan buatan terhadap pertumbuhan dan kelangsungan hidup ikan betutu, <em>Oxyeleotris marmorata</em> (Blkr.). Rancangan faktorial dengan 2 faktor, bentuk pakan (pelet basah dan pelet kering) dan sumber protein (ikan, cumi dan udang) digunakan dalam penelitian ini. Ikan diberi pakan 7% bobot badan basah yang diberikan dalam 3 kali per hari. Ikan yang diberi pakan dengan kombinasi bentuk pelet basah dan sumber protein udang (pelet basah-udang) menunjukkan kelangsungan hidup, pertumbuhan, efisiensi pemberian pakan dan retensi protein terbaik dari perlakuan lainnya. Udang dan cumi dapat digunakan sebagai sumber protein utama dalam pakan buatan untuk ikan betutu. Pakan buatan untuk benih ikan betutu disarankan mengandung atraktan dan memiliki stabilitas dalam air yang tinggi.</span></p><p class="MsoNormal"><span style="font-size: 11pt;" lang="in" xml:lang="in">Kata kunci :<span>  </span>Pemberian pakan, pakan buatan, ikan betutu, <em>Oxyeleotris marmorata</em>, benih.</span></p>

Further Studies on Predator Induction of Crests in Australian Daphnia and the Effects of Crests on Predation

1985 ◽  
Vol 36 (4) ◽  
pp. 519 ◽  
Author(s):  
M.J Barry ◽  
I.A.E Bayly
Keyword(s):  
Growth Rate ◽  
Comparative Study ◽  
Predator Avoidance ◽  
Laboratory Studies ◽  
Predator Density ◽  
Daphnia Population ◽  
The One ◽  
Intrinsic Mortality ◽  
Predator Induction

The effects of notonectid predation on populations of Daphnia in a controlled seminatural environment were studied. Log crest size was positively correlated with predator density, suggesting that crest induction was not an all-or-nothing type of response. The size of the Daphnia population varied inversely with notonectid density. Laboratory studies indicated that a crest-induction factor was produced by all Anisops spp. and the one species of Enithares that were tested. Two forms of D. carinata s.1. differed in their ability to respond to the same species of notonectid. Non-notonectid predators did not induce crests. Results of predation experiments supported previously published indications that helmets reduce the efficiency of notonectid predation. The effect of the helmet varied, depending on the species of notonectid and the size and form of D. carinata s.1. The crest acted primarily to increase predator avoidance by evasion rather than by escape. A comparative study of an ecophenotypic morph and a permanently crested morph showed that the presence of a crest was associated with reduced fecundity. The growth rate of the permanently crested morph during this experiment was slower, although its intrinsic mortality was considerably higher.

The threshold energy for atom displacement in fcc metals

1990 ◽  
Vol 48 (4) ◽  
pp. 530-531
Author(s):  
Wilfried Sigle ◽  
Matthias Hohenstein ◽  
Alfred Seeger
Keyword(s):  
Growth Rate ◽  
Elevated Temperatures ◽  
Threshold Energy ◽  
Dislocation Loops ◽  
Absolute Minimum ◽  
Voltage Electron ◽  
Atom Displacement ◽  
Electron Microscopes ◽  
Fcc Metal

Prolonged electron irradiation of metals at elevated temperatures usually leads to the formation of large interstitial-type dislocation loops. The growth rate of the loops is proportional to the total cross-section for atom displacement,which is implicitly connected with the threshold energy for atom displacement, Ed . Thus, by measuring the growth rate as a function of the electron energy and the orientation of the specimen with respect to the electron beam, the anisotropy of Ed can be determined rather precisely. We have performed such experiments in situ in high-voltage electron microscopes on Ag and Au at 473K as a function of the orientation and on Au as a function of temperature at several fixed orientations.Whereas in Ag minima of Ed are found close to <100>,<110>, and <210> (13-18eV), (Fig.1) atom displacement in Au requires least energy along <100>(15-19eV) (Fig.2). Au is thus the first fcc metal in which the absolute minimum of the threshold energy has been established not to lie in or close to the <110> direction.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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