The effect of prey availability on metabolism and activity in the tarantula Phormictopus cancerides

2010 ◽  
Vol 88 (1) ◽  
pp. 90-98 ◽  
Author(s):  
B. N. Philip ◽  
C. Shillington
Keyword(s):  
Prey Capture ◽  
Prey Availability ◽  
Locomotory Activity ◽  
Prey Detection ◽  
Metabolic Rates ◽  
Feeding Trial ◽  
Detection Distance ◽  
Feeding Behaviors ◽  
Limited Food ◽  
Feeding Trials

Spiders typically exhibit very low resting metabolic rates (RMR) and altered feeding behaviors as mechanisms to survive extended periods of limited food availability. We examined the effect of different periods of food deprivation on RMR and foraging activities in the Hispaniolan giant tarantula ( Phormictopus cancerides (Latreille, 1806)) (Araneae: Theraphosidae). Juvenile tarantulas were separated into two feeding groups and fed once either every 5 or 30 days. Monthly feeding trials were preceded by RMR measurements. During feeding trials, we compared differences between the two groups in (i) prey capture frequency, (ii) time to prey capture, (iii) locomotory activity, and (iv) the predator’s prey detection distance. Metabolic rates increased for the well-fed group but remained constant for individuals fed once a month. Time to prey capture decreased for food-limited individuals and the proportion of individuals that ate during each feeding trial was significantly higher in the 30-day group. Conversely, results for locomotory activity and detection distances were inconclusive.

Water velocity influences prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss irideus)

2008 ◽  
Vol 65 (2) ◽  
pp. 266-275 ◽  
Author(s):  
John J Piccolo ◽  
Nicholas F Hughes ◽  
Mason D Bryant
Keyword(s):  
Oncorhynchus Mykiss ◽  
Prey Capture ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Species Interaction ◽  
Water Velocity ◽  
Capture Probability ◽  
Prey Detection ◽  
Detection Distance ◽  
Drift Feeding

We examined the effects of water velocity on prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (sea-run rainbow trout, Oncorhynchus mykiss irideus) in laboratory experiments. We used repeated-measures analysis of variance to test the effects of velocity, species, and the velocity × species interaction on prey capture probability, prey detection distance, and swimming speeds during prey capture. We used 3D video analysis to assess the spatial and temporal characteristics of prey detection and capture. Coho and steelhead showed significant, velocity-dependent decreases in capture probability (~65% to 10%, with an increase of velocity from 0.29 to 0.61 m·s-1) and prey detection distance, with no effect of species and no velocity × species interaction. Neither velocity nor species affected prey interception speed; fish intercepted prey at their predicted maximum sustainable swimming speed (Vmax) at all velocities. Speed of return to the focal point increased significantly with increasing velocity, with no effect of species. At faster velocities, return speeds were faster than Vmax, indicating potential increases in energetic cost because of anaerobic swimming. The 3D analysis suggests that the reduction in capture probability was due to both reduced prey detection distance and a uniform decline in detection probability within the prey capture area.

Impact of Diet on Metabolism and Swimming Performance in Juvenile Lake Trout, Salvelinus namaycush

1989 ◽  
Vol 46 (3) ◽  
pp. 384-388 ◽  
Author(s):  
F. W. H. Beamish ◽  
J. C. Howlett ◽  
T. E. Medland
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Lake Trout ◽  
Swimming Performance ◽  
Salvelinus Namaycush ◽  
Feeding Trial ◽  
Direct Association ◽  
Feeding Trials ◽  
Velocity Increments ◽  
Isocaloric Diets

Juvenile lake trout, Salvelinus namaycush, of similar size were fed one of three isocaloric diets, each differing in protein and lipid content. Oxygen consumption and swimming performance were measured in a recirculating water flume at intervals throughout the 70-d feeding trials (10 °C). Swimming speed was increased by stepwise velocity increments (5 cm∙s−1) and oxygen consumption was measured at each velocity between 20 and 45 cm∙s−1. Oxygen consumption for a given speed did not differ significantly throughout the feeding trial nor among the diets implying a similarity in the quality and quantity of substrate catabolized for energy. Basal metabolism (0 cm∙s−1) was also independent of diet and feeding interval. Critical swimming speed increased with dietary and carcass protein content to suggest a direct association with muscle mass and number of myofilaments.

An experimental analysis of prey availability for sanderlings (Aves: Scolopacidae) feeding on sandy beach crustaceans

1980 ◽  
Vol 58 (9) ◽  
pp. 1564-1574 ◽  
Author(s):  
J. P. Myers ◽  
S. L. Williams ◽  
F. A. Pitelka
Keyword(s):  
Prey Density ◽  
Prey Capture ◽  
Prey Size ◽  
Prey Availability ◽  
Capture Rate ◽  
Search Time ◽  
Beach Sand ◽  
Sand Surface ◽  
Prey Capture Rate ◽  
Bodega Bay

We investigated the role of prey size, prey depth, prey microdistribution, and substrate penetrability in affecting prey availability to sanderlings (Calidris alba Pallas). Five experiments were performed in the laboratory manipulating these availability factors and prey density in beach sand. The effects on prey risk and sanderling prey capture rate were measured.Prey risk increased linearly with prey size. Prey within 10 mm of the surface were vulnerable to predation but their risk decreased sharply below that depth. Substrate penetrability affected prey risk by controlling how deeply a sanderling could probe beneath the sand surface while searching for prey.Prey capture rates varied between 0.01 and 0.84 captures per second of search time over a range of prey density between 60 and 1200 prey per square metre. Prey size and substrate penetrability affected capture rate through their effect on prey risk, and substrate penetrability also influenced capture rate directly. Prey density had the strongest effect on prey capture rate. Measurements in the field around Bodega Bay, California, indicate that prey density, prey size, prey depth, and substrate penetrability can have significant impact on sanderling foraging under field conditions.

A test of optimal foraging and the effects of predator experience in the lizards Sceloporus jarrovii and Sceloporus virgatus

Behaviour ◽  
2010 ◽  
Vol 147 (8) ◽  
pp. 933-951 ◽  
Author(s):  
Keyword(s):  
Success Rate ◽  
Prey Capture ◽  
Prey Availability ◽  
Search Time ◽  
Handling Time ◽  
Foraging Efficiency ◽  
Prey Choice ◽  
Foraging Experience ◽  
Time Optimality ◽  
Sceloporus Virgatus

AbstractForaging efficiency of predators can be evaluated by using optimality or profitability models which incorporate prey choice, handling time and pursuit or search time. Optimality of a diet could vary based on the age, sex, size, predation risk, or foraging experience of the predator. This study tested the effects of a predator's age and foraging experience by observing prey capture attempts and success rate, and by calculating diet profitability for adult and neonate Sceloporus jarrovii and adult Sceloporus virgatus. Prey availability was assessed in order to determine prey preference and profitability. Neonates showed an increased number of prey capture attempts, but success rate was similar for neonates and adults of both species. Total diet profitability of neonates was lower than adults of either species, which could be a result of poor prey choice or gape limitation (although body size showed no direct effect). Overall, the diets of all three groups were less profitable than would be expected based on the types of prey in the environment, although this is likely due to low availability (from the lizard's perspective) of highly profitable items. Lizards seem to be eating prey items in the same proportion as they are found in the environment.

scholarly journals AN ESTIMATION OF THE VARIABILITY IN THE COMPOSITION OF ORTS FROM FEEDING TRIALS WITH LACTATING COWS

1979 ◽  
Vol 59 (1) ◽  
pp. 113-131
Author(s):  
L. J. FISHER
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Composite Sample ◽  
Regression Analyses ◽  
Feeding Trial ◽  
Acid Detergent Fiber ◽  
Lactating Cows ◽  
Feeding Trials ◽  
Forage Mixtures

A total of 320 samples of feed refusals (orts) were obtained from 16 cows fed four different forage mixtures. These samples of orts were analyzed for dry matter, protein, acid detergent fiber and lignin. The observations on amount of orts expressed as kilograms of dry matter or percent of intake and the chemical composition of orts were statistically analyzed to determine differences between cows and rations. Regression analyses were run to determine the influence of amount of weighback on its chemical composition. Analyses of the data indicated that there were differences between rations in the degree of selection that cows exhibited for protein and for acid detergent fiber. These data indicated that there are substantial differences among cows in their ability to select components of a mixed silage ration. The results of this study demonstrated the need to obtain individual weighback samples for each cow on a feeding trial rather than obtaining a composite sample. It was suggested that the feeding of complete feeds to lactating cows may not necessarily result in a uniform consumption of nutrients.

scholarly journals Effects of supplementing ragi (Eleusine coracana) diets with lysine or leaf protein on the growth and nitrogen metabolism of children

1969 ◽  
Vol 23 (4) ◽  
pp. 737-743 ◽  
Author(s):  
T. R. Doraiswamy ◽  
Narendra Singh ◽  
V. A. Daniel
Keyword(s):  
Nutritional Status ◽  
Protein Content ◽  
Nitrogen Retention ◽  
Eleusine Coracana ◽  
Leaf Protein ◽  
Apparent Digestibility ◽  
Feeding Trial ◽  
N Retention ◽  
Feeding Trials

1. Diets based on ragi (Eleusine corucum) (1) were supplemented with L-lysine monohydrochloride (2) to provide 0.50 g additional lysine per day, or with lucerne leaf protein (3) to provide the same amount of lysine as 2, or with sesame flour (4) to provide the same amount of protein as 3. The effects of such supplementation on the growth and nutritional status of twenty children fed on each diet were studied in a feeding trial lasting for 6 months. Nitrogen retention and apparent digestibility of the diets were also studied at one stage during the feeding trials.2. Supplementing ragi diets with any of the materials brought about improvement in all nutritional responses, i.e. height, weight, general nutritional status, apparent digestibility and N retention. The diet supplemented with leaf protein led to the greatest response in growth, as measured by increase in height and weight, followed by those supplemented with lysine and sesame flour in that order.3. The apparent digestibility of the lysine-supplemented diet was lower than those of the diets supplemented with leaf protein and sesame flour.4. The differences in N retention between the children on the three supplemented diets were not significant.5. The most important observations were that, although lysine as a sole supplement improved the quality of ragi diets, the leaf protein was superior to it because it improved the quality and increased the content of protein in the diet, and that the sesame flour, in spite of increasing the protein content, did not provide adequate lysine.

scholarly journals Diets and Seasonal Ingestion Rates of Aurelia coerulea (Cnidaria: Scyphozoa) Polyps by in situ Feeding Experiments in Jiaozhou Bay, China

2021 ◽  
Vol 8 ◽  
Author(s):  
Wang Pengpeng ◽  
Zhang Fang ◽  
Guo Dongjie ◽  
Sun Song
Keyword(s):  
Prey Capture ◽  
Prey Availability ◽  
Ingestion Rate ◽  
Jiaozhou Bay ◽  
Gut Contents ◽  
Natural Diet ◽  
Ingestion Rates ◽  
Aurelia Coerulea ◽  
Feeding Experiments

The benthic scyphopolyp population is an important stage in the scyphozoan lifecycle. Nevertheless, few studies have detailed the natural feeding and quantified the energy flux of polyps based on field research. To better understand the scyphopolyp natural diet and seasonal variation patterns in the ingestion rate, in situ feeding experiments were conducted on Aurelia coerulea polyps in Jiaozhou Bay, China from August 2018 to April 2019. The diet of A. coerulea polyps was determined by gut content analysis. Digestion rates were also measured. Ingestion rates, based on the gut contents and digestion rates, were assessed monthly. Copepods, copepod nauplii, and ciliates were identified in the guts of A. coerulea polyps. Copepods with the bulk of total prey intake in number are an important source of nutrition for A. coerulea polyps in Jiaozhou Bay. Prey capture of A. coerulea polyps (prey polyp–1) varied among months, and was highly dependent upon the abundance of planktonic prey in the habitat. Copepods and copepod nauplii were digested more rapidly as temperature increased. Carbon weight-specific ingestion rate exhibited an obvious seasonal change, with the mean value of 0.13 ± 0.12 μg C μg C–1 d–1. More rapid digestion of prey at higher temperatures and larger prey availability would cause a higher ingestion rate in polyps. Scyphopolyps are widely distributed predators in littoral ecosystems and they may play an important role in plankton–benthos coupling by transferring energy from the water column to the benthos. Massive scyphopolyps blooms may influence pelagic ecosystems.

THE FEEDING VALUE OF POTATO STEAM PEEL FOR GROWING-FINISHING PIGS

1989 ◽  
Vol 69 (1) ◽  
pp. 225-234 ◽  
Author(s):  
T. A. VAN LUNEN ◽  
D. M. ANDERSON ◽  
A.-M. ST. LAURENT ◽  
J. W. G. NICHOLSON ◽  
P. R. DEAN
Keyword(s):  
Growth Performance ◽  
Dry Matter ◽  
Enzyme Inhibitors ◽  
Feed Consumption ◽  
Finishing Pigs ◽  
Feeding Trial ◽  
First Feeding ◽  
Feeding Value ◽  
Feeding Trials ◽  
Inclusion Level

Potato steam peel (SP) is a by-product of potato processing where the peel is removed after steaming. It typically contains 15 ± 3% dry matter, 16 ± 1% crude protein, 0.55 ±.05% lysine, 0% methionine/cystine and 6% ash (dry matter basis). Steaming effectively deactivates the proteolytic enzyme inhibitors and partially denatures the starch. SP was evaluated in a digestibility trial and at levels from 0 to 30% DM in two feeding trials. The digestibility (%) of SP by pigs was found to be 88.4 (DM), 80.1 (CP) and 86.1 (DE). In the first feeding trial diets containing levels of 0, 10, 15, 20, 25 and 30% SP supplemented with methionine resulted in similar growth performance and carcass characteristics. In the second feeding trial, a comparison was made between a constant level of inclusion and an increase in inclusion level with age. Results showed no difference in growth performance or feed consumption among treatments. It is concluded that SP can be incorporated in diets for growing-finishing pigs at levels up to 30% DM. No change in performance resulted from increasing level of inclusion with age. Key words: Potato, steam peel, pigs, digestibility

Feeding kinematics of juvenile swellsharks, Cephaloscyllium ventriosum

1997 ◽  
Vol 200 (8) ◽  
pp. 1255-1269 ◽  
Author(s):  
L Ferry-Graham
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Buccal Cavity ◽  
Video Recording ◽  
Large Prey ◽  
Feeding Behaviors ◽  
Suction Index ◽  
Item Size ◽  
Prey Items ◽  
Cephaloscyllium Ventriosum

To investigate how feeding behaviors change with prey size, high-speed video recording was used to examine the kinematics of prey capture and transport in 1-year-old swellsharks Cephaloscyllium ventriosum (Scyliorhinidae: Carchariniformes) feeding on two differently sized prey items. Prey capture in these sharks generally consisted of an initially ram-dominated capture bite, one or more manipulation bites, a holding phase during which the food was held in the teeth of the shark, and then suction-dominated prey transport. During initial capture and transport, most of the water taken in is forced back out of the mouth anteriorly rather than continuing posteriorly out through the gill openings. Dye experiments in which dye-perfused prey items were ingested by the sharks confirm this observation; distinct jets of colored water were video-taped as they were ejected from the mouth. Very late in prey transport, a bolus of water is ejected through the gill slits; however, by this time, the majority of water appears already to have exited the buccal cavity through the mouth. Such patterns were observed for sharks feeding on both small and large prey items. Although a basic pattern of prey capture and transport was regularly repeated among strikes, kinematic patterns during prey capture and transport were variable both within and among individuals, indicating that prey acquisition is not tightly controlled. However, the amount of variability was similar among prey sizes. In addition, there were no detectable changes in behavior due to prey item size. Ram-suction index values confirmed that similar capture modes were being utilized for both prey sizes.

Prey-capture behavior in gymnotid electric fish: motion analysis and effects of water conductivity

2001 ◽  
Vol 204 (3) ◽  
pp. 543-557 ◽  
Author(s):  
M.A. MacIver ◽  
N.M. Sharabash ◽  
M.E. Nelson
Keyword(s):  
Prey Capture ◽  
Body Position ◽  
Sensory Information ◽  
Orienting Response ◽  
Signal Acquisition ◽  
Three Dimensional Model ◽  
Water Conductivity ◽  
Detection Distance ◽  
Surrounding Water ◽  
Prey Capture Behavior

Animals can actively influence the content and quality of sensory information they acquire from the environment through the positioning of peripheral sensory surfaces. This study investigated receptor surface positioning during prey-capture behavior in weakly electric gymnotiform fish of the genus Apteronotus. Infrared video techniques and three-dimensional model-based tracking methods were used to provide quantitative information on body position and conformation as black ghost (A. albifrons) and brown ghost (A. leptorhynchus) knifefish hunted for prey (Daphnia magna) in the dark. We found that detection distance depends on the electrical conductivity of the surrounding water. Best performance was observed at low water conductivity (2.8 cm mean detection distance and 2 % miss rate at 35 microS cm(−)(1), A. albifrons) and poorest performance at high conductivity (1.5 cm mean detection distance and 11 % miss rate at 600 microS cm(−)(1), A. albifrons). The observed conductivity-dependence implies that nonvisual prey detection in Apteronotus is likely to be dominated by the electrosense over the range of water conductivities experienced by the animal in its natural environment. This result provides the first evidence for the involvement of electrosensory cues in the prey-capture behavior of gymnotids, but it leaves open the possibility that both the high-frequency (tuberous) and low-frequency (ampullary) electroreceptors may contribute. We describe an electrosensory orienting response to prey, whereby the fish rolls its body following detection to bring the prey above the dorsum. This orienting response and the spatial distribution of prey at the time of detection highlight the importance of the dorsal surface of the trunk for electrosensory signal acquisition. Finally, quantitative analysis of fish motion demonstrates that Apteronotus can adapt its trajectory to account for post-detection motion of the prey, suggesting that it uses a closed-loop adaptive tracking strategy, rather than an open-loop ballistic strike strategy, to intercept the prey.

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