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.

Foraging behaviour of oystercatchers Haematopus ostralegus during a diet switch from worms Nereis diversicolor to clams Scrobicularia plana

1989 ◽  
Vol 67 (9) ◽  
pp. 2225-2231 ◽  
Author(s):  
J. Sherman Boates ◽  
John D. Goss-Custard
Keyword(s):  
Food Intake ◽  
Foraging Behaviour ◽  
Capture Rate ◽  
Handling Time ◽  
Intake Rate ◽  
Nereis Diversicolor ◽  
Scrobicularia Plana ◽  
Haematopus Ostralegus ◽  
Food Value ◽  
Food Intake Rate

On the mudflats of the Exe Estuary in southwest England, oystercatchers Haematopus ostralegus switched from eating worms Nereis diversicolor to clams Scrobicularia plana during autumn. A decline in the profitability of worms (from 17 to 4 mg/s handling time) and the food intake of oystercatchers eating worms (from 1300 to < 200 mg/15 min) occurred prior to and during the switch to clams. Declines in profitability and food intake rate were due to seasonal changes in the size and food value of worms available to oystercatchers. Capture rate on worms varied little prior to, or during, the switch. Oystercatchers appeared to switch diets in response to changes in the reward offered by worms rather than in response to relative changes in the reward offered by the two prey species. This is because individual oystercatchers were never observed eating a mixed diet of worms and clams, and may explain why it took 6 weeks (11 October to 25 November) for the population to complete the switch.

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.

Foraging behaviour of Carcinus maenas on Mytilus edulis: the importance of prey presentation

2000 ◽  
Vol 80 (5) ◽  
pp. 799-810 ◽  
Author(s):  
Alexandra Burch ◽  
Raymond Seed
Keyword(s):  
Mytilus Edulis ◽  
Foraging Behaviour ◽  
Prey Size ◽  
Prey Selection ◽  
Carapace Width ◽  
Carcinus Maenas ◽  
Relative Number ◽  
Handling Time ◽  
Median Percentage ◽  
Edge Chipping

The manner in which mussels, Mytilus edulis, are presented to Carcinus maenas significantly influences crab prey-selection, resulting in different foraging behaviour. Handling techniques, breaking and handling times, percentage flesh eaten and prey value curves were compared when mussels of the following size-classes, 5–10, 10–15, 15–20, 20–25, 25–30 mm shell length, were presented singly and when they were presented as part of a group to crabs of 30–55 mm carapace width. When prey were presented singly, crabs used four size-specific opening techniques; outright crushing and directed crushing were used on smaller prey whilst boring and edge-chipping were used on larger, more resistant mussels. However, when mussels were presented as part of a group, boring and edge-chipping were never observed since larger mussels were not consumed. Handling time increased exponentially with mussel size irrespective of how mussels were presented, but, when crabs fed on mussels presented as part of a group, handling times tended to be shorter than when they fed on similar-sized mussels presented singly. The median percentage of flesh left uneaten in discarded shells ranged between 9.58 and 25.25% and was significantly greater than the median percentage of flesh left in the shells of mussels presented singly, which ranged between 4.66 and 14.70%. All resultant prey value curves were convex in shape, but the predicted optimal prey size altered with modifications in prey presentation. Similarly, when crabs of 30–65 mm carapace width were presented with groups of mussels comprised of different proportions of different sizes of mussels, size-class vulnerability was not fixed but altered significantly with the relative proportions in which these were presented. Thus, when the relative number of mussels in the smaller size groups were increased so was their vulnerability, indicating that prey size preference is flexible and not fixed.

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.

Foraging behaviour of Armadillidium vulgare (Isopoda: Oniscidea) in heterogeneous environments

Behaviour ◽  
2004 ◽  
Vol 141 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Joanne Tuck ◽  
Mark Hassall
Keyword(s):  
Leaf Litter ◽  
Foraging Behaviour ◽  
Walking Speed ◽  
Optimal Foraging Theory ◽  
Heterogeneous Environments ◽  
Intake Rate ◽  
High Quality ◽  
Turning Angle ◽  
Quality Food ◽  
Armadillidium Vulgare

AbstractForaging behaviour of Armadillidium vulgare was observed in laboratory arenas in which the spatial distribution of patches of high quality food (powdered dicotyledonous leaf litter) was varied within a background of low quality food (powdered grass leaf litter). The hypotheses that the foraging behaviour and foraging path of A. vulgare would be influenced by food quality and the patchiness of high quality food resources were tested. More time was spent in high quality food patches than in low quality food backgrounds than expected by chance in all heterogeneity treatments, but an increasingly higher percentage of time was spent in low quality food as the high quality food became more clumped in space. More time was spent searching, but less time was spent feeding in low quality food backgrounds than in high quality food patches in all the treatments. Walking speed was found to be lower in high quality food patches than in low quality food backgrounds and this was not affected by treatment. Turning frequency and turning angle were found to be higher in high quality food patches than in low quality backgrounds. Turning frequency in low quality food backgrounds decreased as the high quality food became more clumped in space, whereas turning angle in high quality food patches significantly increased in the patchy, but then decreased again in the clumped treatment. The effects of varying the spatial heterogeneity of high quality foods on the trade-off between costs of searching and intake benefits for saprophages are discussed in relation to predictions from optimal foraging theory for circumstances when intake rate maximisation is affected by the constraint of limited nutrients.

scholarly journals Energy Allocation and Postnatal Growth in Captive Elegant Tern (Sterna Elegans) Chicks: Responses to High-Versus Low-Energy Diets

The Auk ◽  
2003 ◽  
Vol 120 (4) ◽  
pp. 1069-1081 ◽  
Author(s):  
Wasila M. Dahdul ◽  
Michael H. Horn
Keyword(s):  
Prey Species ◽  
Wing Length ◽  
Energy Content ◽  
Daily Intake ◽  
High Energy ◽  
Low Energy ◽  
Intake Rate ◽  
Chick Survival ◽  
Digestive Organs ◽  
Gut Passage

Abstract Effects of variable energy intake on chick growth, organ development, and gut-passage time in seabirds were investigated by raising Elegant Tern (Sterna elegans) chicks in the laboratory on three diets involving a major prey species, northern anchovy (Engraulis mordax), and a minor prey species, topsmelt (Atherinops affinis). Anchovies are ∼25% higher in energy content than topsmelt and represent a more abundant but highly fluctuating prey resource. Chicks were raised from age 15 to age 35 days posthatch on one of three diets (n = 8): (1) high-energy anchovy at the average daily intake rate, (2) low-energy topsmelt at the same intake rate, and (3) high-energy topsmelt (i.e. at a biomass equal in energy content to the anchovy diet). Chicks raised on the high-energy anchovy diet had a significantly faster gain of body mass and wing length. All three groups, however, had attained a statistically similar wing length at 35 days posthatch and did not differ in lean dry mass or pectoral muscle mass, indicating that energy was allocated preferentially toward wing development and flight capacity. Most digestive organs were heavier and gut-passage rates faster for chicks fed topsmelt. Bill dimensions and tarsus length showed little difference among chicks on the three diets. Lipid content of chicks that were fed anchovy was twice that of those fed low-energy topsmelt and one-third higher than that of chicks on the high-energy topsmelt diet. Our results indicate that Elegant Terns have evolved certain capacities for growth and digestion in response to variable prey quality that may increase the probability of chick survival. Nevertheless, if Elegant Tern chicks were switched to a lower quality, primarily topsmelt diet, they would be underweight at fledging with heavier digestive organs, lower lipid reserves, and faster gut-passage times, which would place added provisioning demands on the parents. Under that scenario, the prospects for survival and long-term reproductive success might diminish for such an Elegant Tern colony.

Effects of cadmium on the foraging behavior and growth of juvenile bluegill, Lepomis macrochirus

1995 ◽  
Vol 52 (8) ◽  
pp. 1630-1638 ◽  
Author(s):  
Miehael D. Bryan ◽  
Gary J. Atchison ◽  
Mark B. Sandheinrich
Keyword(s):  
Foraging Behavior ◽  
Standardized Test ◽  
Prey Capture ◽  
Prey Size ◽  
Cadmium Concentration ◽  
Control Level ◽  
Lepomis Macrochirus ◽  
Aquatic Organisms ◽  
Handling Time ◽  
Behavioral Measure

Standardized test protocols for assessing chemical hazards to aquatic organisms inadequately consider behavioral effects of toxicants; yet, organisms behaving abnormally in the wild have reduced growth, reduced fitness, and high mortality. We determined the chronic effects of cadmium (0, 30, 60, 120, and 240 μg∙L−1) on juvenile bluegill (Lepomis macrochirus) foraging behavior and growth rates in functional response experiments, each using different sized Daphnia as prey. Bluegill consumption rate increased with prey density. Cadmium-exposed fish initially attacked fewer prey per unit of time than unexposed fish, with subsequent recovery to control-level consumption rates determined by cadmium concentration and prey size. The degree of change (over time) in the number of Daphnia attacked per 30 s was the most consistently sensitive behavioral measure of sublethal stress in exposed bluegill; the lowest observed effect concentration (LOEC) was 37.3 μg Cd∙L−1. Effects on prey attack rates (attacks/30 s) were inversely related to prey size; cadmium had the greatest effect on bluegill foraging on the smallest prey. Cadmium had no effect on prey capture efficiency or handling time. Growth in bluegill length and weight was reduced (P ≤ 0.019) by all cadmium concentrations and was a more sensitive end point than were the foraging behaviors.

Optimal prey size for stream resident brown trout (Salmo trutta): tests of predictive models

1986 ◽  
Vol 64 (3) ◽  
pp. 704-713 ◽  
Author(s):  
Eileen Bannon ◽  
Neil H. Ringler
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Prey Size ◽  
Food Resource ◽  
Handling Time ◽  
Minimum Size ◽  
Small Fish ◽  
Order Stream ◽  
Mouth Size ◽  
Brown Trout Salmo Trutta

The time required to handle different-sized prey (crickets) was measured in an artificial stream for eight wild brown trout (Salmo trutta L.) in two size classes (mean total lengths, 186 and 214 mm). Handling times (HTs) scaled by mouth size were described by an exponential equation: HT = 1 + 0.84e2.35(ps/ms) (ps, prey size; ms, predator (mouth) size). Cost curves based on handling time/prey weight were used to predict optimal prey lengths of 22 mm for small trout and 24 mm for large trout. A second model based on J. W. J. Wankowski's empirical results predicted slightly smaller optima. Physical constraints provided estimated minimum prey lengths of 2.8 and 3.2 mm for large and small fish, respectively; maximum prey lengths were 89 and 97 mm, respectively. We compared the predicted optimal prey size with the size distribution of invertebrates in drift and brown trout stomachs sampled in a second-order stream from July to September 1982. The most abundant prey sizes in the study stream were near the minimum size that can be effectively handled by brown trout. Prey of the predicted optimum size were rare, but feeding was size selective in spite of a limited food resource. The growth rates of these stream-dwelling brown trout were slower than the brown trout in other streams in this region. This may reflect diets consisting largely of suboptimal-sized prey.

Discerning the diets of sweep-feeding eurypterids: assessing the importance of prey size to survivorship across the Late Devonian mass extinction in a phylogenetic context

Paleobiology ◽  
2020 ◽  
pp. 1-13
Author(s):  
Emily S. Hughes ◽  
James C. Lamsdell
Keyword(s):  
Mass Extinction ◽  
Prey Species ◽  
Size Range ◽  
Prey Size ◽  
Phylogenetic Signal ◽  
Late Devonian ◽  
Evolutionary Trend ◽  
Average Spacing ◽  
Horseshoe Crabs ◽  
Mode Of Life

Abstract Eurypterids are generally considered to comprise a mixture of active nektonic to nektobenthic predators and benthic scavenger-predators exhibiting a mode of life similar to modern horseshoe crabs. However, two groups of benthic stylonurine eurypterids, the Stylonuroidea and Mycteropoidea, independently evolved modifications to the armature of their anterior appendages that have been considered adaptations toward a sweep-feeding life habit, and it has been suggested the evolution toward sweep-feeding may have permitted stylonurines to capture smaller prey species and may have been critical for the survival of mycteropoids during the Late Devonian mass extinction. There is a linear correlation between the average spacing of feeding structures and prey sizes among extant suspension feeders. Here, we extrapolate this relationship to sweep-feeding eurypterids in order to estimate the range of prey sizes that they could capture and examine prey size in a phylogenetic context to determine what role prey size played in determining survivorship during the Late Devonian. The mycteropoid Cyrtoctenus was the most specialized sweep-feeder, with comblike appendage armature capable of capturing mesoplankton out of suspension, while the majority of stylonurines possess armature corresponding to a prey size range of 1.6–52 mm, suggesting they were suited for capturing small benthic macroinvertebrates such as crustaceans, mollusks, and wormlike organisms. There is no clear phylogenetic signal to prey size distribution and no evolutionary trend toward decreasing prey sizes among Stylonurina. Rather than prey size, species survivorship during the Late Devonian was likely mediated by geographic distribution and ability to capitalize on the expanding freshwater benthos.

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