Differential Predation by Chaoborus americanus on Males and Females of Two Species of Diaptomus

1993 ◽  
Vol 50 (2) ◽  
pp. 410-415 ◽  
Author(s):  
Jules M. Blais ◽  
Edward J. Maly
Keyword(s):  
Prey Species ◽  
Calanoid Copepod ◽  
Prey Size ◽  
Handling Time ◽  
Prey Type ◽  
Feeding Rates ◽  
Feeding Experiments ◽  
Chaoborus Americanus ◽  
Differential Predation ◽  
Males And Females

Feeding experiments were performed to determine relative feeding rates of fourth-instar Chaoborus americanus larvae (Diptera) on both sexes of two calanoid copepod species, Diaptomus leptopus and D. minutus. Feeding rates, using a single prey type, showed that predation rates by Chaoborus on female D. minutus were highest, followed by male D. minutus, male D. leptopus, and female D. leptopus, respectively, when exposed to Chaoborus individually. Selectivity experiments with the four prey types made available simultaneously confirmed this pattern. Prey sizes and swimming speeds were determined, and both strike efficiency and handling time of Chaoborus were measured. Data suggested that selection between prey species was determined primarily by prey size whereas selection between sexes was determined primarily by differential swimming speed.

The Relationship Between Prey Size and Handling Time and Prey Size and Capture Success in 3 Sympatric Species of Dasyurid Marsupials

1988 ◽  
Vol 15 (6) ◽  
pp. 615 ◽  
Author(s):  
MC Calver ◽  
JS Bradley ◽  
DR King
Keyword(s):  
Linear Regression ◽  
Prey Size ◽  
Handling Time ◽  
Prey Type ◽  
Sympatric Species ◽  
Niche Separation ◽  
Simple Linear Regression ◽  
Predator Species ◽  
The Relationship ◽  
Better Than

Regressions of handling time on prey weight were determined for the dasyurids Srninthopsis hirtipes, S. ooldea and Ningaui spp. preying on grasshoppers and cockroaches in the laboratory. In all cases, a simple linear regression fitted the relationships better than logarithmic models. The slopes of the regression lines were steeper for grasshopper prey than for cockroach prey in all species, and for each prey type the slopes for the predators were ranked in order of predator weight. Capture efficiency, defined as the proportion of successful attacks, did not vary significantly between predator species and prey types, and all predators showed declining capture efficiencies with increasing prey size. Niche separation in these dasyurids does not appear to be based on different optimal prey sizes for each species.

Predation by juvenile piscivorous bluefish (Pomatomus saltatrix): the influence of prey to predator size ratio and prey type on predator capture success and prey profitability

1998 ◽  
Vol 55 (7) ◽  
pp. 1695-1703 ◽  
Author(s):  
Frederick S Scharf ◽  
Jeffrey A Buckel ◽  
Francis Juanes ◽  
David O Conover
Keyword(s):  
Striped Bass ◽  
Prey Species ◽  
Handling Time ◽  
Prey Type ◽  
Continuous Functions ◽  
Pomatomus Saltatrix ◽  
Frequency Distributions ◽  
Atlantic Silverside ◽  
Capture Success ◽  
Prey Vulnerability

Capture success, handling time, prey vulnerability, and prey profitability were examined as a function of prey length/predator length ratio for age-0 juvenile bluefish (Pomatomus saltatrix) feeding on juvenile striped bass (Morone saxatilis) and Atlantic silverside (Menidia menidia). For each prey species, bluefish capture success declined linearly and handling time increased exponentially with increasing length ratios between 0.20 and 0.65. However, bluefish capture success was lower and handling times increased at a faster rate when feeding on juvenile striped bass compared with Atlantic silverside. Prey vulnerability, measured as bluefish predation rate, declined exponentially with increasing length ratios for each prey species. Profitability curves were dome shaped for each prey species; however, profitability values and the location of dome peaks differed between prey species. Capture success functions were combined with field length distributions to generate expected frequency distributions of length ratios included in bluefish diets. Comparisons resulted in good agreement between expected and observed sizes in bluefish diets, illustrating the importance of capture success in determining piscivore diets. Our results indicate that, for juvenile fishes, prey-specific morphological and behavioral differences can have significant effects on the outcome of predator-prey interactions and that size-based predation components are best represented as continuous functions of relative fish size.

Habitats, diets, and sympatry in snakes: a study from Australia

1977 ◽  
Vol 55 (7) ◽  
pp. 1118-1128 ◽  
Author(s):  
Richard Shine
Keyword(s):  
Species Diversity ◽  
Competitive Exclusion ◽  
Prey Species ◽  
Prey Size ◽  
Empirical Work ◽  
Prey Type ◽  
Published Data ◽  
Potential Prey ◽  
Climatic Regions ◽  
Eastern Australia

Six species of elapid snakes were studied in a highlands region of eastern Australia. Major results were as follows. (1) These snakes are opportunistic feeders, relatively unselective with respect to prey type or prey size. (2) Despite this unselective feeding, over 60% of the diet (by weight) in all species consists of lizards and frogs. Published data show a preponderance of these prey types in Australian snakes as a whole, and I suggest that this is due to the scarcity of other potential prey items (especially small mammals and freshwater fish) in Australia. (3) Sympatry is less common in the elapids studied than among North American snakes in comparable climatic regions. I attribute the scarcity of sympatry among the Australian snakes to the restricted number of prey types available. This argument is supported by previous empirical work which suggests that prey species diversity determines snake species diversity. Observed prey-size differences between sympatric elapid species are consistent with the interpretation of interspecific competitive exclusion.

Carnivorous Suspension Feeding by the Subarctic Calanoid Copepod Neocalanus cristatus

1988 ◽  
Vol 45 (6) ◽  
pp. 1069-1074 ◽  
Author(s):  
Charles H. Greene ◽  
Michael R. Landry
Keyword(s):  
Calanoid Copepod ◽  
Prey Size ◽  
Prey Selection ◽  
Suspension Feeding ◽  
Calanoid Copepods ◽  
Pelagic Ecosystem ◽  
Foraging Mode ◽  
Feeding Experiments ◽  
Feeding Modes

Carnivorous suspension feeding is described for the large subarctic calanoid copepod Neocalanus cristatus. This foraging mode relies on the use of a feeding current to entrain potential prey items and transport them into the copepod's capture area. The extensive use of a feeding current to entrain and transport prey into the capture area distinguishes carnivorous suspension feeding from the predatory modes typically described for other calanoid copepods. The consequences of carnivorous suspension feeding on N. cristatus' prey-selection patterns are significant. Feeding experiments reveal that the vulnerability of naupliar prey declines with increasing prey size, just the opposite result observed for other marine calanoids exhibiting more typical predatory feeding modes. The role of omnivorous feeding by N. cristatus within the pelagic ecosystem of the subarctic Pacific is also discussed. In contrast with earlier hypotheses, the results reported here are consistent with the emerging view that this large suspension-feeding copepod may be having at least as great an impact on the microzooplankton as on the phytoplankton of the region.

Foraging patterns of California sea otters as indicated by telemetry

1995 ◽  
Vol 73 (3) ◽  
pp. 523-531 ◽  
Author(s):  
Katherine Ralls ◽  
Brian B. Hatfield ◽  
Donald B. Siniff
Keyword(s):  
Foraging Behavior ◽  
Prey Size ◽  
Prey Type ◽  
Dive Duration ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Foraging Patterns ◽  
Radio Transmitters ◽  
Males And Females ◽  
Juvenile Males

Foraging behavior was studied in 38 sea otters (Enhydra lutris) implanted with radio transmitters. The observed foraging behavior of instrumented individuals was similar to that of uninstrumented otters observed in previous studies: dive duration varied with prey type but not with prey size, dive success was highest for small prey, and the length of surface intervals increased with prey size. However, telemetry revealed that some otters foraged farther offshore and made longer dives than was indicated by visual observations. Individuals within age–sex classes varied in several aspects of foraging behavior, including the duration of dives and length of surface intervals. There were no overall differences between the dive durations or surface intervals during the day and during the night, though some individuals had longer dives or surface intervals during either the day or the night. There were differences in the foraging behavior of the various age–sex classes, the most striking being those between juvenile males and females. Juvenile males foraged much farther offshore [Formula: see text] in deeper water [Formula: see text] than other otters and made long dives during both the day [Formula: see text] and the night [Formula: see text]. Juvenile females fed for longer periods than other otters.

Feeding behaviour of predatory larvae of Atherix lantha Webb (Diptera: Athericidae)

1994 ◽  
Vol 72 (10) ◽  
pp. 1695-1699 ◽  
Author(s):  
Fiona F. Hunter ◽  
Astrid K. Maier
Keyword(s):  
Feeding Behaviour ◽  
Prey Species ◽  
Prey Size ◽  
Prey Type ◽  
Predator Prey ◽  
Size Classes ◽  
Predator Size ◽  
Oxygenated Water

Larvae of Atherix lantha Webb (Diptera: Athericidae) are piercing – sucking predators. Predator–prey experiments were conducted in beakers containing gravel substrates and airstone-oxygenated water. The predator:prey ratio used in all experiments was 5:5. One prey type was tested at a time. Prey tested included large and small heptageniid mayflies, hyalellid amphipods, and hydropsychid caddisflies. The effect of predator size was examined using two size classes of A. lantha larvae. Large A. lantha consumed more mayflies than did small A. lantha. However, amphipod mortality was the same with large as with small A. lantha. The effect of prey size on predation success was tested using two size classes of mayflies. Statistically, small A. lantha fed on equal numbers of small and large mayflies, whereas large A. lantha consumed more large than small mayflies. Data for species-wise comparisons are only available for small A. lantha; according to our results, hydropsychid caddisflies (average mortality (m) = 0.5346) are more vulnerable to predation than are hyalellid amphipods (m = 0.2041) and heptageniid mayflies (m = 0.1135–0.1813). However, the mortality of large mayflies caused by large A. lantha larvae (m = 0.5375) is the same as that of caddisflies caused by small A. lantha larvae. Thus, the vulnerability of prey species depends, in part, on predator size.

scholarly journals The Diet of the Magnificent Frigatebird During Chick Rearing

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 569-576 ◽  
Author(s):  
Itzia Calixto-Albarrán ◽  
José-Luis Osorno
Keyword(s):  
Diet Composition ◽  
Pacific Coast ◽  
Prey Species ◽  
Prey Size ◽  
The Pacific ◽  
Prey Composition ◽  
Males And Females ◽  
Changes Over Time ◽  
Over Time ◽  
Opportunistic Feeding

Abstract We describe the diet of the Magnificent Frigatebird Fregata magnificens at Isla Isabel off the Pacific coast of Mexico based on 158 regurgitates (555 prey items) from males, females, chicks, and juveniles. The diet included 50 species of fishes (21 identified to genus only), 1 species of squid, and 2 species of crustaceans. Diplectum pacificum and Anchoa lucida were the most frequent species of fish in the frigatebird's diet. No differences in prey composition or prey size were found between males and females, but females disgorged 62% more food. This difference mirrors the bigger size (15% larger than males) and larger contribution of females to chick feeding. Flying juveniles consumed prey in different proportions than the adults and disgorged marginally more food. Juveniles may obtain food in different patches than adults and complement this source with maternal feedings, or they may be more likely to regurgitate. Diet composition of males, females, and flying juveniles changed during the 4-month period of this study, but the mass of regurgitates did not change as the breeding season progressed, suggesting that availability of prey species changes over time. Most of the diet of this population probably comes from opportunistic feeding on fisheries, because the variety of fishes disgorged is remarkably similar to the published list of fishes discarded by prawn-fishing boats in the area. If our assumption is true, kleptoparasitism and direct fishing are only marginally represented in the diet of this population.

scholarly journals Functional Response and Predation Rate of Dicyphus cerastii Wagner (Hemiptera: Miridae)

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 530
Author(s):  
Gonçalo Abraços-Duarte ◽  
Susana Ramos ◽  
Fernanda Valente ◽  
Elsa Borges da Silva ◽  
Elisabete Figueiredo
Keyword(s):  
Functional Response ◽  
Prey Species ◽  
Prey Size ◽  
Handling Time ◽  
Petri Dish ◽  
Predation Rate ◽  
Horticultural Crops ◽  
Predation Capacity ◽  
Interesting Candidate ◽  
High Predation

Dicyphine mirids are important biological control agents (BCAs) in horticultural crops. Dicyphus cerastii Wagner can be found in protected tomato crops in Portugal, and has been observed feeding on several tomato pests. However, the predation capacity of this species is poorly studied. In order to investigate the predation capacity of D. cerastii, and how it is affected by prey size and mobility, we evaluated the functional response (FR) and predation rate of female predators on different densities of four prey species: Myzus persicae 1st instar nymphs (large mobile prey), Bemisia tabaci 4th instar nymphs, Ephestia kuehniella eggs (large immobile prey) and Tuta absoluta eggs (small immobile prey). Experiments were performed on tomato leaflets in Petri dish arenas for 24 h. Dicyphus cerastii exhibited type II FR for all prey tested. The predator effectively preyed upon all prey, consuming an average of 88.8 B. tabaci nymphs, 134.4 E. kuehniella eggs, 37.3 M. persicae nymphs and 172.3 T. absoluta eggs. Differences in the FR parameters, attack rate and handling time, suggested that prey size and mobility affected predation capacity. Considering the very high predation rates found for all prey species, D. cerastii proved to be an interesting candidate BCA for tomato crops.

scholarly journals Response of Australian pied oystercatchersHaematopus longirostristo increasing abundance of the beach bivalve preyDonax deltoides

2018 ◽  
Author(s):  
Stephen L. Totterman
Keyword(s):  
Functional Response ◽  
Breeding Season ◽  
Feeding Ecology ◽  
Prey Species ◽  
Prey Size ◽  
New South ◽  
Feeding Rates ◽  
Future Studies ◽  
Adult Plumage ◽  
South Wales

AbstractThis study measured the response of Australian pied oystercatchersHaematopus longirostrison South Ballina Beach, New South Wales, Australia during a recovery in the stock of the primary prey speciesDonax deltoides, a large beach clam and commonly known as the ‘pipi’. It was predicted that oystercatcher counts would increase when pipi abundance increased (numerical response) and that oystercatcher feeding rates would also increase (functional response). Between Oct 2009 and Mar 2015, mean pipi density increased from c. zero to 30 pipis/m2. Mean oystercatcher feeding rates increased to an asymptote of c. 0.26 pipis/min. Breeding season mean counts of adult-plumage oystercatchers increased from 23 to 43, largely driven by non-territorial birds. Prey size selection was absent, both among different prey types and among pipis > 20 mm. This report provides some insights into the feeding ecology of oystercatchers on sandy ocean beaches that should be valuable in planning future studies.

Foraging behaviour of oystercatchers Haematopus ostralegus specializing on different species of prey

1992 ◽  
Vol 70 (12) ◽  
pp. 2398-2404 ◽  
Author(s):  
J. Sherman Boates ◽  
John D. Goss-Custard
Keyword(s):  
Foraging Behaviour ◽  
Prey Species ◽  
Prey Size ◽  
Handling Time ◽  
Littorina Littorea ◽  
Intake Rate ◽  
Prefer Prey ◽  
Rate Maximization ◽  
Scrobicularia Plana ◽  
Haematopus Ostralegus

Adult oystercatchers Haematopus ostralegus specializing on four prey species, the mussel Mytilus edulis, the winkle Littorina littorea, the ragworm Nereis diversicolor, and the clam Scrobicularia plana, were compared. Some clear trends from mussels to winkles to clams to worms were identified. First, mean biomass (size) of prey decreased but more prey were attacked per unit time and, since fewer attacks were aborted, more prey were actually captured per unit time. Second, handling time decreased, and birds raised their heads less often while handling a prey item and carried prey less frequently. Third, foraging density, attack rate, and avoidance rate all decreased. However, average rates of food intake did not follow the same order and were inconsistent with the expected preference for prey. The greatest intake rate was achieved by birds specializing on clams, the least preferred prey. The rate of intake of mussels, the most preferred prey, was significantly lower. Alternatives to the energy rate maximization model to explain prey preference are discussed and dismissed. The results of this study contrast with those from several studies on prey-size selection within a single prey species, which show that oystercatchers prefer prey that maximize their intake rates. We suggest that the basis for selecting a prey species and for selecting different size classes within one prey species may be quite different.

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