Journal articles: 'Prey size'

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Hampton, Paul M. "Ontogenetic prey size selection in snakes: predator size and functional limitations to handling minimum prey sizes." Zoology 126 (February 2018): 103–9. http://dx.doi.org/10.1016/j.zool.2017.11.006.

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Luiselli, Luca, Godfrey C. Akani, Claudia Corti, and Francesco M. Angelici. "Is sexual size dimorphism in relative head size correlated with intersexual dietary divergence in West African forest cobras, Naja melanoleuca?" Contributions to Zoology 71, no. 4 (2002): 141–45. http://dx.doi.org/10.1163/18759866-07104004.

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Sex-biased differences in dietary habits of snakes are often linked to pronounced sexual size dimorphism in absolute body size or in relative head size. We studied the food habits of free-ranging forest cobras (Naja melanoleuca) in southern Nigeria to find whether any intersexual dietary divergence is present in this species, and measured both museum vouchers and free-ranging specimens to find whether any intersexual divergence in relative head size is present. We demonstrated that: (1) head sizes increases more rapidly with SVL in females than in males, with a result that, at the same body length, the females tended to have significantly larger heads; (2) males and females were nearly identical in dietary habits, both if we consider prey size or prey type; (3) both sexes tended to prey upon relatively little sized preys. It is concluded that traditional evolutionary scenarios for explaining sexual dimorphism and food niche divergence are hardly valid in this case, and we need to look for entirely different hypotheses (e.g. linked to the sexual preference of males for females with larger heads).

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Bannon, Eileen, and Neil H. Ringler. "Optimal prey size for stream resident brown trout (Salmo trutta): tests of predictive models." Canadian Journal of Zoology 64, no. 3 (March 1, 1986): 704–13. http://dx.doi.org/10.1139/z86-104.

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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.

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Houston, A. I. "Prey size of single-prey loaders as an indicator of prey abundance." Ecology Letters 3, no. 1 (January 2000): 5–6. http://dx.doi.org/10.1046/j.1461-0248.2000.00110.x.

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Rychlik, L. "Prey size, prey nutrition, and food handling by shrews of different body sizes." Behavioral Ecology 13, no. 2 (March 1, 2002): 216–23. http://dx.doi.org/10.1093/beheco/13.2.216.

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Tonn, W. M., C. A. Paszkowski, and I. J. Holopainen. "Selective piscivory by perch: Effects of predator size, prey size, and prey species." SIL Proceedings, 1922-2010 24, no. 4 (September 1991): 2406–11. http://dx.doi.org/10.1080/03680770.1989.11899975.

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McLean, Edward B. "Sexual dimorphism and predaceous feeding habits of the waterstrider Gerris remigis Say (Heteroptera: Gerridae)." Canadian Journal of Zoology 68, no. 12 (December 1, 1990): 2688–91. http://dx.doi.org/10.1139/z90-371.

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The feeding habits of Gerris remigis were examined in a southeastern Ontario stream. Gerrids with prey items were collected from two pools along a 15-m length of the site. The size distribution of potential prey available in the surface drift during the survey was estimated. Gerrid prey consisted mainly of terrestrial insects; coleopterans, dipterans, homopterans, and hymenopterans represented the predominant orders. The median size of prey taken by all gerrids was significantly larger than that available in the surface drift. A sexual dimorphism in gerrid body size was found. The length of prey taken did not differ between the sexes; however, the diet of the larger bodied females consisted of prey with a greater median body width than the diet of smaller males. Females also took a greater size range of prey. These results support a size-dependent predation model which predicts that the upper size range of prey that can be successfully captured is correlated with predator size.

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Sabagh, Leandro Talione, Ana Maria Paulino Telles Carvalho-e-Silva, and Carlos Frederico Duarte Rocha. "Diet of the toad Rhinella icterica (Anura: Bufonidae) from Atlantic Forest Highlands of southeastern Brazil." Biota Neotropica 12, no. 4 (December 2012): 258–62. http://dx.doi.org/10.1590/s1676-06032012000400027.

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In this study, we present some information of the regarding throphic niche from the anuran toad Rhinella icterica living in high altitudes above 2000 m a.s.l. from a habitat of the Atlantic Forest Biome - the Altitude Fields in the Itatiaia National Park. We found 150 prey items in toad stomachs, belonging to five prey types, as well as skin remains and some remains of plant material. The index of relative importance indicated that most important prey types were beetles and ants, these last composing 70% of the diet numerically and the trophic niche breadth (B) was 1.81. The relatively low diversity of prey types we recorded in the diet of R. icterica of Itatiaia and numerically dominated by ants suggests some preference for this item. We do not found significant relationship between the toad measurements with the preys' measurements. We concluded that R. icterica toads at the highlands of Itatiaia feeds on arthropods, mainly ants and coleopterans and that the high consumption of preys with relatively small and similar size as ants in the diet prevents an expected relationship among frog body or mouth size and prey volume and size.

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Jensen, Hallvard, Kimmo K. Kahilainen, Per-Arne Amundsen, Karl Øystein Gjelland, Antti Tuomaala, Tommi Malinen, and Thomas Bøhn. "Predation by brown trout (Salmo trutta) along a diversifying prey community gradient." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 9 (September 2008): 1831–41. http://dx.doi.org/10.1139/f08-096.

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Predation has a fundamental role in aquatic ecosystems, but the relative importance of factors governing prey selection by predators remains controversial. In this study, we contrast five lakes of a subarctic watershed to explore how prey community characteristics affect prey selection and growth rate of the common top predator, brown trout ( Salmo trutta ). The lakes constitute a distinct gradient of different coregonid prey fish, ranging from monomorphic common whitefish ( Coregonus lavaretus ) to polymorphic whitefish co-occurring with vendace ( Coregonus albula ). The brown trout was a morph–species- and size-specific pelagic predator, selecting the small-sized, pelagic whitefish morph or vendace over the benthic whitefish morphs. In all lakes, the average prey size increased with predator size, but small-sized prey were also included in the diet of large predators. The selection of small-sized, pelagic prey fish appeared to be a favourable foraging strategy for the brown trout, yielding higher growth rates and an earlier ontogenetic shift to piscivory. The findings emphasize that piscivory appear to be shaped by the diversity, size-structure, and abundance of available prey in a given community.

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Woolnough, AP, and SM Carthew. "Selection of Prey by Size in Ningaui Yvonneae." Australian Journal of Zoology 44, no. 3 (1996): 319. http://dx.doi.org/10.1071/zo9960319.

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The small dasyurid marsupial, Ningaui yvonneae, feeds opportunistically on invertebrates dominated by the orders Hymenoptera, Coleoptera and Araneae, but is capable of, and will, consume vertebrates such as skinks. When presented with a choice of prey N. yvonneae exhibited a strong preference for prey items on the basis of size. It consistently selected small prey items over large prey items. Small prey items represented the most energy-efficient prey option as the ningaui can more efficiently capture, subdue and consume them than it can larger prey. The relationship between prey size and handling time was exponential, indicating that there is an upper limit to the ability of N. yvonneae to process prey. Moreover, smaller cockroaches provided greater energy gain than larger ones, indicating that the costs of eating larger cockroaches energetically outweighed the energy return. These results are in agreement with optimal foraging theory.

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Mayer, C. M., and D. H. Wahl. "The relationship between prey selectivity and growth and survival in a larval fish." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 7 (July 1, 1997): 1504–12. http://dx.doi.org/10.1139/f97-056.

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We examined prey preference, growth, and survival of small larval (8-10 mm total length (TL)), large larval (11-17 mm TL), and early juvenile (>18 mm TL) walleye (Stizostedion vitreum) in laboratory aquaria and field mesocosms using multiple prey assemblages that included cladoceran, copepod, and rotifer prey of varied sizes. Both prey taxa and size affected prey preference during the larval period. All sizes of walleye avoided rotifer and nauplii prey. Small and large larvae selected for intermediate-sized (0.4-0.9 mm) cladoceran prey and selected against large prey (>0.9 mm) of both taxa. Although neither capture efficiency nor handling time differed between prey taxa, larvae oriented more frequently towards cladoceran prey suggesting that they were more visible than copepods to these small fish. Larval walleye that were fed exclusively cladoceran prey survived better than fish that were fed other prey. Early juveniles selected primarily on the basis of prey size, choosing large copepods and cladocerans. Prey taxa did not affect early juvenile growth or survival. Prey taxa and prey size interacted with predator size to influence selectivity and its effect on growth and survival. Consequently, these factors must be considered in combination when examining the importance of foraging decisions in young fish.

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Schoener, Thomas W., Jonathan Roughgarden, and Tom Fenchel. "The Body-Size-Prey-Size Hypothesis: A Defense." Ecology 67, no. 1 (February 1986): 260–61. http://dx.doi.org/10.2307/1938528.

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Levinton, Jeffrey S. "The Body Size-Prey Size Hypothesis and Hydrobia." Ecology 68, no. 1 (February 1987): 229–31. http://dx.doi.org/10.2307/1938827.

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Cherrill, Andrew J. "The Shell Size: Prey Size Relationship in Mudsnails." Oikos 51, no. 1 (January 1988): 110. http://dx.doi.org/10.2307/3565817.

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Collins, M. A., and G. J. Pierce. "Size selectivity in the diet of Loligo forbesi (Cephalopoda: Loliginidae)." Journal of the Marine Biological Association of the United Kingdom 76, no. 4 (November 1996): 1081–90. http://dx.doi.org/10.1017/s0025315400040972.

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The size of fish and squid prey of Loligo forbesi was investigated using otoliths, beaks and statoliths collected from stomach contents analysis of samples obtained from Scottish and Irish waters between 1990 and 1993. Loligo forbesi was found to consume a large range of prey sizes, but prey size was always less than the predator size. Season was shown to significantly influence the predator size-prey size relationship for sprat and sandeel prey, but this itself could be influenced by seasonal changes in the size of prey. Fish prey size increased with increased predator size up to a mantle length (ML) of 200 mm. Loligo forbesi of mantle length >200 mm consumed a range of prey sizes, with no clear increase in the size of prey. For most prey taxa the relationship between prey size and squid size was similar, the exceptions being dragonets and silvery pout. Cannibalism by L. forbesi was mostly limited to larger L. forbesi (>150 mm ML) feeding on smaller (20–50 mm ML) conspecifics.

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Gibert, Jean P., and John P. DeLong. "Temperature alters food web body-size structure." Biology Letters 10, no. 8 (August 2014): 20140473. http://dx.doi.org/10.1098/rsbl.2014.0473.

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The increased temperature associated with climate change may have important effects on body size and predator–prey interactions. The consequences of these effects for food web structure are unclear because the relationships between temperature and aspects of food web structure such as predator–prey body-size relationships are unknown. Here, we use the largest reported dataset for marine predator–prey interactions to assess how temperature affects predator–prey body-size relationships among different habitats ranging from the tropics to the poles. We found that prey size selection depends on predator body size, temperature and the interaction between the two. Our results indicate that (i) predator–prey body-size ratios decrease with predator size at below-average temperatures and increase with predator size at above-average temperatures, and (ii) that the effect of temperature on predator–prey body-size structure will be stronger at small and large body sizes and relatively weak at intermediate sizes. This systematic interaction may help to simplify forecasting the potentially complex consequences of warming on interaction strengths and food web stability.

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Lundvall, David, Richard Svanbäck, Lennart Persson, and Pär Byström. "Size-dependent predation in piscivores: interactions between predator foraging and prey avoidance abilities." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 7 (July 1, 1999): 1285–92. http://dx.doi.org/10.1139/f99-058.

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Body size is known to play a crucial role in predator-prey interactions. For a given predator size, it has been suggested that prey mortality should be a dome-shaped function dependent on prey body size. In this study, we experimentally tested (i) the suggested mechanisms responsible for the dome-shaped prey vulnerability function and (ii) whether a prey refuge affected the form of this function. As prey, we used young-of-the-year Eurasian perch (Perca fluviatilis), and as predator, larger Eurasian perch. The prey mortality as a function of prey size was dome shaped for large and medium predators but decreased monotonically with prey size for small predators. Capture success of predators decreased monotonically with increasing prey size and was lower for small predators. In refuge trials, the mortality of prey declined monotonically with prey size for all predator sizes. Refuge use of prey increased with the sizes of both prey and predator. Our results suggest that the hypothesized dome-shaped relationship on prey vulnerability can be altered by the presence of an absolute prey refuge. Our results further suggest that the ability to perform more flexible foraging behaviors is of increasing importance when prey size increases.

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Calver, MC, JS Bradley, and DR King. "The Relationship Between Prey Size and Handling Time and Prey Size and Capture Success in 3 Sympatric Species of Dasyurid Marsupials." Wildlife Research 15, no. 6 (1988): 615. http://dx.doi.org/10.1071/wr9880615.

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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.

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Dodrill, Michael J., Charles B. Yackulic, Theodore A. Kennedy, and John W. Hayes. "Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 5 (May 2016): 759–72. http://dx.doi.org/10.1139/cjfas-2015-0268.

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The cold and clear water conditions present below many large dams create ideal conditions for the development of economically important salmonid fisheries. Many of these tailwater fisheries have experienced declines in the abundance and condition of large trout species, yet the causes of these declines remain uncertain. Here, we develop, assess, and apply a drift-foraging bioenergetics model to identify the factors limiting rainbow trout (Oncorhynchus mykiss) growth in a large tailwater. We explored the relative importance of temperature, prey quantity, and prey size by constructing scenarios where these variables, both singly and in combination, were altered. Predicted growth matched empirical mass-at-age estimates, particularly for younger ages, demonstrating that the model accurately describes how current temperature and prey conditions interact to determine rainbow trout growth. Modeling scenarios that artificially inflated prey size and abundance demonstrate that rainbow trout growth is limited by the scarcity of large prey items and overall prey availability. For example, shifting 10% of the prey biomass to the 13 mm (large) length class, without increasing overall prey biomass, increased lifetime maximum mass of rainbow trout by 88%. Additionally, warmer temperatures resulted in lower predicted growth at current and lower levels of prey availability; however, growth was similar across all temperatures at higher levels of prey availability. Climate change will likely alter flow and temperature regimes in large rivers with corresponding changes to invertebrate prey resources used by fish. Broader application of drift-foraging bioenergetics models to build a mechanistic understanding of how changes to habitat conditions and prey resources affect growth of salmonids will benefit management of tailwater fisheries.

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Villares Junior, GA, and R. Goitein. "Variations of Salminus hilarii diet (Ostariophysi, Characidae): seasonal and ontogenetic effects." Brazilian Journal of Biology 75, no. 3 (September 25, 2015): 574–80. http://dx.doi.org/10.1590/1519-6984.17213.

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AbstractThis study described the variations seasonal and ontogenetic of Salminus hilarii diet. Samples were collected in the Sorocaba River, São Paulo, Brazil, one of the few rivers where individuals of the species still occur in a higher frequency. The preys consumed were analyzed by Importance Alimentary Index (AIi). To determine similarities between year seasons, the AIi data were analyzed by the Morisita-Horn index and reduced in cluster analysis, along with a statistical comparison made by one-way ANOSIM test (5%). The feeding activity was analyzed according to the stomach repletion index and compared among the year seasons using non parametric variance analysis Kruskal-Wallis test (5%). Comparison of prey consumed between immature and adult individuals was made by Spearman correlation (5%). A Pearson correlation (5%) was applied between the standard length of the fish and prey consumed, as well as between the mouth and prey heights. The analyzes of stomach contents showed that the diet of this species was exclusively piscivorous, with significant difference of prey consumption during the period, the same happening among adult and immature individuals. It was observed that these fishes use to swallow their prey whole and that significant correlations between size of predator and prey size can be observed. There is also correlation between the mouth height and the maximum prey depth. Salminus hilarii feeds on the available prey, and the species food composition and feeding activity depends on prey`s abundance, their size and morphology, as do the water temperatures.

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Hatcher, Christopher R., and Adam G. Hart. "Venus Flytrap Seedlings Show Growth-Related Prey Size Specificity." International Journal of Ecology 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/135207.

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Venus flytrap (Dionaea muscipula) has had a conservation status of vulnerable since the 1970s. Little research has focussed on the ecology and even less has examined its juvenile stages. For the first time, reliance on invertebrate prey for growth was assessed in seedling Venus flytrap by systematic elimination of invertebrates from the growing environment. Prey were experimentally removed from a subset of Venus flytrap seedlings within a laboratory environment. The amount of growth was measured by measuring trap midrib length as a function of overall growth as well as prey spectrum. There was significantly lower growth in prey-eliminated plants than those utilising prey. This finding, although initially unsurprising, is actually contrary to the consensus that seedlings (traps < 5 mm) do not catch prey. Furthermore, flytrap was shown to have prey specificity at its different growth stages; the dominant prey size for seedlings did not trigger mature traps. Seedlings are capturing and utilising prey for nutrients to increase their overall trap size. These novel findings show Venus flytrap to have a much more complex evolutionary ecology than previously thought.

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Enders, Margit M., and Paul I. Ward. "Conflict and Cooperation in the Group Feeding of the Social Spider Stegodyphus Mimosarum." Behaviour 94, no. 1-2 (1985): 167–82. http://dx.doi.org/10.1163/156853985x00325.

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Abstract1. Stegodyphus mimosarum, a social spider, lives in colonies which may contain hundreds of individuals. Feeding behaviour was examined with respect to feeding group size and prey size. 2. Prey were less likely to escape and were subdued more quickly when attacked by more than one spider. 3. During capture small prey were frequently bitten directly on the body whereas large prey were almost always bitten on an appendage. 4. Pulling struggles for subdued prey occurred. They lasted longest over medium sized prey. Small prey were easier to transport to the nest than medium prey and large prey were pulled by more spiders from a single retreat. 5. Spiders which had participated in a capture initially bit preferentially on the prey's head or thorax but others which joined later to feed bit at random. 6. Feeding became less efficient as group size increased and an experiment suggests that individuals injected less poison and digestive enzymes when feeding in groups.

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Hahn, Norma Segatti, Rosilene Luciana Delariva, and Valdirene Esgarbosa Loureiro. "Feeding of Acestrorhynchus lacustris (Characidae): a post impoundment studies on Itaipu reservoir, upper Paraná River, PR." Brazilian Archives of Biology and Technology 43, no. 2 (2000): 207–13. http://dx.doi.org/10.1590/s1516-89132000000200010.

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With objective to know feeding spectrum of Acestrorhynchus lacustris (Reinhardt, 1874), a middle size predator in different places of influence area of Itaipu reservoir, stomach contents were analyzed. Samples were collected from March 1984 to February 1989 from Itaipu Reservoir and its adjacent areas. Its fed mainly on fishes, but it was an opportunistic (consumed 17 species of prey). Despite of the wide feeding spectrum, few preys were dominant in the diet, according to the different habitats sampled. As a result, it significant spatial differences in the diet was observed. Was observed through "Detrented Correspondence Analysis" (DCA) these were divided into three groups in relation with diet: preys from upstream, with higher scores; preys from the reservoir, with intermediate scores; and preys from a tributary with smaller scores. This discrimination may be a function of prey availability in each habitat. The mean size of preys consumed increased with the size of the predator, as well as the variance, i. e. the largest fish also consumed small preys.

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Laursen, Karsten, and Anders Pape Møller. "Brain mass explains prey size selection better than beak, gizzard and body size in a benthivorous duck species." PLOS ONE 16, no. 3 (March 30, 2021): e0248615. http://dx.doi.org/10.1371/journal.pone.0248615.

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Prey size selection in some bird species is determined by the size of the beak. However, we assumed for bird species swallowing whole prey that a cognitive process may be involved. As cognitive feature, brain mass was used. We hypothesized that the mass of the brain was more strongly positively correlated with prey size than morphological features such as beak volume, gizzard mass and body mass. We tested this hypothesis on eiders Somateria mollissima that swallow the prey whole, by using mean and maximum size of nine prey categories. Eiders were collected at the main wintering grounds in Denmark. As index of brain mass we used head volume, which is positively correlated with brain mass (r2 = 0.73). Head volume of eiders was significantly, positive correlated with mean and maximum size of blue mussels Mytilus edulis, razor clams Ensis directus and all prey sizes combined and the maximum size of draft whelk Hinia reticulata and conch Buccinum undatum. Gizzard mass was also significantly positively correlated with maximum size of draft whelk and conch. Beak volume and body mass was not significantly correlated with the size of any of the nine food items. Analyses of effect size for organs showed that head volume was positively related to prey size, whereas beak volume, gizzard mass and body mass did not show a significant positive relationship. These results indicate that cognitive processes connected to brain mass may be involved in prey size selection by eiders.

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Keeley, E. R., and JWA Grant. "Allometry of diet selectivity in juvenile Atlantic salmon (Salmo salar)." Canadian Journal of Fisheries and Aquatic Sciences 54, no. 8 (August 1, 1997): 1894–902. http://dx.doi.org/10.1139/f97-096.

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Juvenile salmonids in streams typically feed on larger invertebrates than the average size available in the drift. Our objective was to describe the allometry of this size-selective foraging in juvenile Atlantic salmon, Salmo salar of Catamaran Brook, New Brunswick. We compared paired samples of the stomach contents of 46 salmon (age 0 + to 2 + ; fork length 2.9-14.5 cm) with drift samples collected from their feeding territories. Juvenile salmon fed opportunistically on all major types of invertebrates in the drift, except for water mites (Hydracarina). However, newly emerged salmon fed on smaller prey than the average available in the drift, primarily chironomid larvae, whereas salmon larger than 4.6 cm fed on larger prey than average, primarily dipteran adults and pupae. Larger salmon ate larger prey. Minimum prey length in stomachs was well predicted by gill raker spacing, but mean prey width was only one third of the optimal size and maximum prey width was much less than mouth width. The allometry of prey size appeared to be related primarily to an increase in size-selective foraging with increasing body size, rather than to morphological constraints. Juvenile Atlantic salmon in our study ate smaller prey than similar-sized salmonids in other studies.

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Johnson, Andrew F., Maria Valls, Joan Moranta, Stuart R. Jenkins, Jan G. Hiddink, and Hilmar Hinz. "Effect of prey abundance and size on the distribution of demersal fishes." Canadian Journal of Fisheries and Aquatic Sciences 69, no. 1 (January 2012): 191–200. http://dx.doi.org/10.1139/f2011-138.

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Many demersal fish species rely on benthic prey as food sources for part of, or in some cases, all of their life history. We investigated the relationships between prey and predator abundance and prey size and predator mouth gape size for nine demersal fish species. Of the species analysed, four showed a significant positive increase in abundance with increasing prey abundance. Prey size is thought to be an important parameter for demersal fish that are limited in their feeding potential by their mouth gape size, as it influences consumption rate and energy expenditure while foraging. The relationship between prey size and mouth gape was investigated using both stomach content data and prey availability data. Stomach content analysis revealed positive relationships between maximum prey size and predator mouth gape size for six of the species. Indications of prey size selectivity were only seen in the environment for European hake ( Merluccius merluccius ), highlighting the potential importance of prey size over prey abundance for this species. The results demonstrate that prey abundance and size are of significance for some demersal fish species feeding primarily on benthos and will help in defining habitat requirements of demersal fish species.

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López, Pilar, Pilar López, José Martín, Pilar López, José Martín, and Alfredo Salvador. "Flexibility in feeding behaviour may compensate for morphological constraints of fossoriality in the amphisbaenian Blanus cinereus." Amphibia-Reptilia 34, no. 2 (2013): 241–47. http://dx.doi.org/10.1163/15685381-00002879.

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Morphological adaptations for burrowing, such as an elongated body, and a small head may constrain feeding behaviour in fossorial reptiles. We experimentally examined the effect of prey type on prey capture and handling behaviour of the amphisbaenian Blanus cinereus. This amphisbaenian showed four different handling modes according to the characteristics of each prey type. When prey diameter was narrower than gape-size, prey were consumed without prey processing; when prey diameter was wider than gape-size, B. cinereus shifted handling mode to prey processing. Amphisbaenians scraped or tore off bite-sized pieces of large prey and showed longer handling times for some prey types than most epigean saurians. Flexibility in feeding behaviour may allow amphisbaenians to exploit variable underground trophic resources, overcoming constraints of morphological adaptation to fossoriality.

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Rincón, Pedro A., and Javier Lobón-Cerviá. "Prey-size selection by brown trout (Salmo trutta L.) in a stream in northern Spain." Canadian Journal of Zoology 77, no. 5 (October 1, 1999): 755–65. http://dx.doi.org/10.1139/z99-031.

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Brown trout in the River Negro in northern Spain preferentially ate larger aquatic prey items (found throughout the water column). A model based on size-dependent prey encounters was able to account for this trend and to generate accurate predictions of the consumption of aquatic prey of different sizes. In contrast, the same model failed to predict the size composition of terrestrial prey (restricted to the upper layers of the water column) eaten bv the trout. Trout ignored the larger (more profitable) terrestrial prey, and the consumption of prey of a given size class was more dependent on their relative abundance than on their size. However, the smallest prey were rejected. We suggest that trout were switching, i.e., overexploiting the most abundant prey, because of perceptual limitations mediated by large differences in relative abundance of the different size classes of terrestrial prey. The size-frequency distributions of the available terrestrial prey were always greatly dominated (75-90%) by the two smallest size classes (1-2 and 2-3 mm long), prey over 4 mm long being extremely scarce, while size distributions of aquatic prey were less skewed. Overall, active choice guided by energetic optimization criteria appeared to be of limited importance in determining the size composition of prey eaten by this population of brown trout Our results also indicate that the operating mechanisms of prey-size selection are probably not independent of the characteristics of the size-frequency distribution of the available prey.

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Huang, Yu-Hsuan, Hsiao-Hang Tao, Gwo-Ching Gong, and Chih-hao Hsieh. "Importance of prey size on investigating prey availability of larval fishes." PLOS ONE 16, no. 5 (May 18, 2021): e0251344. http://dx.doi.org/10.1371/journal.pone.0251344.

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Prey availability plays an important role in determining larval fish survival. Numerous studies have found close relationships between the density of mesozooplankton and larval fishes; however, emerging studies suggest that small-size zooplankton are more important prey for some larval fish species. One arising question is whether the size of zooplankton determines the relationship between zooplankton and larval fish community in natural environments. To address this question, we collected small-size (50–200 μm) zooplankton, mesozooplankton (> 330 μm), and larval fish using three different mesh-size (50, 330, 1000 μm, respectively) nets in the East China Sea, and examined their relationships in density. Both meso- and small-size zooplankton densities showed positive relationships with larval fish density, while the relationship is much stronger for the small-size zooplankton. Specifically, the smallest size classes (50–75 and 75–100 μm) of small-size zooplankton showed the highest positive relationships with larval fish density. Temperature, salinity, and chlorophyll-a concentration did not significantly explain larval fish density. Based on these findings, we demonstrate the importance of considering prey size when investigating prey availability for larval fishes.

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Pizzatto, Lígia, Otavio Marques, and Kátia Facure. "Food habits of Brazilian boid snakes: overview and new data, with special reference to Corallus hortulanus." Amphibia-Reptilia 30, no. 4 (2009): 533–44. http://dx.doi.org/10.1163/156853809789647121.

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AbstractThis study examines the diet of eight boid snakes: Boa c. constrictor, Boa c. amarali, Corallus caninus, C. hortulanus, Epicrates cenchria, E. crassus, E. assisi and Eunectes murinus mainly by analyzing the gut contents of preserved museum specimens, and includes a literature review to present an overview of the diet of Brazilian boids. Mammals constitute the primary prey consumed by the majority of the species. Birds are also frequently consumed by C. hortulanus and Boa contrictor, and are the most important prey for B. c. amarali. Ectotherms (mostly lizards) were only consumed by immature snakes. Such prey is rarely consumed by B. c. amarali and not recorded for Epicrates and Eunectes species in our dissections. C. caninus is likely a mammal specialist and Epicrates prey on birds more opportunistically. The niche overlap index varied from 0.27-0.52 for species occurring in the same bioma and geographic range but it is possible this overlap is lower as most sympatric species explore different macrohabitat. C. hortulanus exhibited a significant relationship between prey size and predator head size; this relationship did not differ among mature and immature snakes. In comparison to immature individuals heavier adult snakes fed on heavier prey items however, the ratio between prey/predator mass decreased with increase in predator mass (or size). Most boids exploit diurnal and nocturnal preys, probably using both sit-and-wait and active tactics. They feed on the ground but boas and C. hortulanus and possibly E. cenchria also exploit arboreal prey.

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Juanes, Francis. "The allometry of cannibalism in piscivorous fishes." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 5 (May 1, 2003): 594–602. http://dx.doi.org/10.1139/f03-051.

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Cannibalism is a widespread phenomenon that can have strong population and community effects. In this study, I compare the prey size predator size relationships of diets with and without cannibalized prey for four piscivorous species and five populations that are commonly cannibalistic and where large databases exist. I then examine the resultant trophic niche breadths (range of relative prey size consumed) to quantify whether inclusion of cannibalized prey in the diet slows down the decline in trophic niche breadth that many large predators exhibit as they grow. When comparing diets including cannibalized prey with those without, consistent differences were found among all predator species. In all cases, the slope of the upper bound of the predator size prey size scatters was larger for cannibal predators compared with noncannibals, suggesting selectivity for larger cannibal prey, which may be driven by higher rates of size-dependent capture success with familiar prey. The slopes of the upper bounds of the cannibal relative prey size vs. predator size scatter also tended to be larger than the upper-bound slopes for diets without conspecific prey. Finally, for all species, mean trophic breadth of diets including cannibalized prey were larger than those not including cannibal prey, suggesting that relatively large prey sizes may always be available for cannibals.

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Ille, Rottraut. "Preference of Prey Size and Profitability in Barn Owls Tyto Alba Guttata." Behaviour 116, no. 3-4 (1991): 180–89. http://dx.doi.org/10.1163/156853991x00021.

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AbstractBarn owls of the subspecies Tyto alba guttata which had been bred in captivity, and which had experience with prey, were examined for preferences in prey size (weight) under experimental conditions. They were offered a choice of larger and smaller prey of three weight classes (3/10 g; 10/40 g; 40/160 g) either active or inactive (laboratory mice, Mus musculus; laboratory rats, Rattus norvegicus). The frequency of choices of smaller prey increased significantly from the lowest to the highest weight class, and from inactive to active prey. Most frequently, the owls selected prey of 10 g and 40 g. It was shown that both prey size and activity had an equal influence on the decisions. Predictions were made as to which particular prey size a barn owl was going to choose. With increasing prey weight, the frequency of interrupted prey catching acts and conflict behaviour (mantling, feather ruffling) towards the prey, increased. The upper weight for acceptable active rats was about 80 g. One male, which had to supply his female and nestlings with food, subdued somewhat larger prey. Although relative profitability (net nutritive value/unit of time), calculated from the duration of handling prey, decreased with increasing prey weight, the barn owls chose the larger prey under certain conditions. I discuss a strategy which compromises time and energy costs with the search and subduction of the item.

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Nalepa, Christine, and Whitney Swink. "Prey carriage varies with prey size in Cerceris fumipennis (Hymenoptera, Crabronidae)." Journal of Hymenoptera Research 44 (June 11, 2015): 49–55. http://dx.doi.org/10.3897/jhr.44.5158.

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Dörner, H., S. Hülsmann, F. Hölker, C. Skov, and A. Wagner. "Size-dependent predator?prey relationships between pikeperch and their prey fish." Ecology of Freshwater Fish 16, no. 3 (September 2007): 307–14. http://dx.doi.org/10.1111/j.1600-0633.2006.00223.x.

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Dörner, H., and A. Wagner. "Size-dependent predator-prey relationships between perch and their fish prey." Journal of Fish Biology 62, no. 5 (May 2003): 1021–32. http://dx.doi.org/10.1046/j.1095-8649.2003.00092.x.

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Rypstra, Ann L., and R. Scott Tirey. "Prey size, prey perishability and group foraging in a social spider." Oecologia 86, no. 1 (March 1991): 25–30. http://dx.doi.org/10.1007/bf00317384.

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Schalk, Christopher M., and Michael V. Cove. "Squamates as prey: Predator diversity patterns and predator-prey size relationships." Food Webs 17 (December 2018): e00103. http://dx.doi.org/10.1016/j.fooweb.2018.e00103.

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King, R. B. "Predicted and observed maximum prey size - snake size allometry." Functional Ecology 16, no. 6 (December 2002): 766–72. http://dx.doi.org/10.1046/j.1365-2435.2002.00678.x.

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Allan, J. David, Alexander S. Flecker, and Nancy L. McClintock. "Prey size selection by carnivorous stoneflies1." Limnology and Oceanography 32, no. 4 (July 1987): 864–72. http://dx.doi.org/10.4319/lo.1987.32.4.0864.

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Ankney, C. Davison. "Prey Size Selection by Tree Swallows." Auk 102, no. 2 (April 1985): 245–50. http://dx.doi.org/10.2307/4086766.

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Skelhorn, John, Hannah M. Rowland, Michael P. Speed, Leoni De Wert, Lucy Quinn, Jon Delf, and Graeme D. Ruxton. "Size-dependent misclassification of masquerading prey." Behavioral Ecology 21, no. 6 (2010): 1344–48. http://dx.doi.org/10.1093/beheco/arq159.

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Jayne, Bruce C., Harold K. Voris, and Peter K. L. Ng. "Snake circumvents constraints on prey size." Nature 418, no. 6894 (July 2002): 143. http://dx.doi.org/10.1038/418143a.

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Close, Matthew, and David Cundall. "Mammals as prey: Estimating ingestible size." Journal of Morphology 273, no. 9 (June 22, 2012): 1042–49. http://dx.doi.org/10.1002/jmor.20042.

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Read, D. G. "Diets of sympatric Planigale gilesi and P. tenuirostris (Marsupialia: Dasyuridae): relationships of season and body size." Australian Mammalogy 10, no. 1 (January 1, 1987): 11–21. http://dx.doi.org/10.1071/am87002.

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The insectivorous diets of Planigale gilesi and P. tenuirostris were studied in the field over a 2-year period by analysis of faeces. Prey items were grouped according to taxonom ic order and size class with the aid of a reference collection. Abundance of potentially available prey was estimated from light trap and pitfall trap data collected during each session of mammal trapping. In all seasons, P. gilesi and P. tenuirostris were generalists with respect to prey type and prey size: prey items in the diet occurred in the same proportions as those in the available prey. Important prey taxa were Coleoptera and Araneida. Large planigales of the same or different species took prey from large size classes that were not utilized by small planigales although all took prey in the small size classes. Approximately 10% of the prey taken by adul ts of the larger species, P. gilesi, was larger than 800 mm3 but P. tenuirostris individuals rarely took prey larger than this size. Body size is a factor that reduces dietary overlap and hence inter- and intraspecific competition.

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García-Comas, Carmen, Akash R. Sastri, Lin Ye, Chun-Yi Chang, Fan-Sian Lin, Min-Sian Su, Gwo-Ching Gong, and Chih-hao Hsieh. "Prey size diversity hinders biomass trophic transfer and predator size diversity promotes it in planktonic communities." Proceedings of the Royal Society B: Biological Sciences 283, no. 1824 (February 10, 2016): 20152129. http://dx.doi.org/10.1098/rspb.2015.2129.

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Body size exerts multiple effects on plankton food-web interactions. However, the influence of size structure on trophic transfer remains poorly quantified in the field. Here, we examine how the size diversity of prey (nano-microplankton) and predators (mesozooplankton) influence trophic transfer efficiency (using biomass ratio as a proxy) in natural marine ecosystems. Our results support previous studies on single trophic levels: transfer efficiency decreases with increasing prey size diversity and is enhanced with greater predator size diversity. We further show that communities with low nano-microplankton size diversity and high mesozooplankton size diversity tend to occur in warmer environments with low nutrient concentrations, thus promoting trophic transfer to higher trophic levels in those conditions. Moreover, we reveal an interactive effect of predator and prey size diversities: the positive effect of predator size diversity becomes influential when prey size diversity is high. Mechanistically, the negative effect of prey size diversity on trophic transfer may be explained by unicellular size-based metabolic constraints as well as trade-offs between growth and predation avoidance with size, whereas increasing predator size diversity may enhance diet niche partitioning and thus promote trophic transfer. These findings provide insights into size-based theories of ecosystem functioning, with implications for ecosystem predictive models.

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Hossie, Thomas John, John Skelhorn, Jesse W. Breinholt, Akito Y. Kawahara, and Thomas N. Sherratt. "Body size affects the evolution of eyespots in caterpillars." Proceedings of the National Academy of Sciences 112, no. 21 (May 11, 2015): 6664–69. http://dx.doi.org/10.1073/pnas.1415121112.

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Many caterpillars have conspicuous eye-like markings, called eyespots. Despite recent work demonstrating the efficacy of eyespots in deterring predator attack, a fundamental question remains: Given their protective benefits, why have eyespots not evolved in more caterpillars? Using a phylogenetically controlled analysis of hawkmoth caterpillars, we show that eyespots are associated with large body size. This relationship could arise because (i) large prey are innately conspicuous; (ii) large prey are more profitable, and thus face stronger selection to evolve such defenses; and/or (iii) eyespots are more effective on large-bodied prey. To evaluate these hypotheses, we exposed small and large caterpillar models with and without eyespots in a 2 × 2 factorial design to avian predators in the field. Overall, eyespots increased prey mortality, but the effect was particularly marked in small prey, and eyespots decreased mortality of large prey in some microhabitats. We then exposed artificial prey to naïve domestic chicks in a laboratory setting following a 2 × 3 design (small or large size × no, small, or large eyespots). Predators attacked small prey with eyespots more quickly, but were more wary of large caterpillars with large eyespots than those without eyespots or with small eyespots. Taken together, these data suggest that eyespots are effective deterrents only when both prey and eyespots are large, and that innate aversion toward eyespots is conditional. We conclude that the distribution of eyespots in nature likely results from selection against eyespots in small caterpillars and selection for eyespots in large caterpillars (at least in some microhabitats).

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Floeter, Jens, and Axel Temming. "Analysis of prey size preference of North Sea whiting, saithe, and grey gurnard." ICES Journal of Marine Science 62, no. 5 (January 1, 2005): 897–907. http://dx.doi.org/10.1016/j.icesjms.2005.03.004.

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Abstract Size preference for prey fish of North Sea whiting, saithe, and grey gurnard was analysed. The analysis combined size-specific prey abundance estimates derived from bottom-trawl surveys with size frequencies of prey in predator stomachs from the International North Sea Stomach Database. To estimate the abundance of all potential prey fish in the sea, predator-specific length-based number spectra were calculated. Prey spectra were weighted by local predator abundance to take the spatial–temporal overlap between predator and their prey into consideration. Species-specific prey size preference models are presented. Contrary to former results, the preferred predator–prey weight ratio of whiting and grey gurnard is an exponentially increasing function of predator size and an exponentially decreasing function of the slope of the number spectrum. When predators grow, they prefer larger prey in absolute units. However, from a species-specific body size onwards they increasingly shift their prey preference towards relatively smaller prey sizes. From a bioenergetic point of view, this behaviour most likely maximizes the predator's foraging efficiency by reducing the expenditure of costly, anaerobically generated energy expended during burst swimming.

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Fossette, Sabrina, Adrian C. Gleiss, James P. Casey, Andrew R. Lewis, and Graeme C. Hays. "Does prey size matter? Novel observations of feeding in the leatherback turtle ( Dermochelys coriacea ) allow a test of predator–prey size relationships." Biology Letters 8, no. 3 (November 16, 2011): 351–54. http://dx.doi.org/10.1098/rsbl.2011.0965.

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Optimal foraging models predict that large predators should concentrate on large prey in order to maximize their net gain of energy intake. Here, we show that the largest species of sea turtle, Dermochelys coriacea , does not strictly adhere to this general pattern. Field observations combined with a theoretical model suggest that a 300 kg leatherback turtle would meet its energetic requirements by feeding for 3–4 h a day on 4 g jellyfish, but only if prey were aggregated in high-density patches. Therefore, prey abundance rather than prey size may, in some cases, be the overriding parameter for foraging leatherbacks. This is a classic example where the presence of small prey in the diet of a large marine predator may reflect profitable foraging decisions if the relatively low energy intake per small individual prey is offset by high encounter rates and minimal capture and handling costs. This study provides, to our knowledge, the first quantitative estimates of intake rate for this species.

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O'Neill, Kevin M. "Egg size, prey size, and sexual size dimorphism in digger wasps (Hymenoptera: Sphecidae)." Canadian Journal of Zoology 63, no. 9 (September 1, 1985): 2187–93. http://dx.doi.org/10.1139/z85-323.

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Female digger wasps invest substantially in each of their offspring, laying relatively few, large eggs and providing the young with the insect prey on which they depend for food. In a study of six species in the genera Philanthus, Bembecinus, and Bembix, it was found that within each species, there is a positive correlation between female body size and both the size of their ovarial eggs and the size of the prey they provision. In five of the six species, females were larger than males on average. It is suggested that the apparent association between body size and certain aspects of parental investment by females may provide the directional selection pressure that results in the evolution of sexual size dimorphism in digger wasps. In one species, males and females have the same mean size, probably because, in this species, selection pressure on male size is similar to that on females.

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Bouwmeester, Mark M., Andreas M. Waser, Jaap van der Meer, and David W. Thieltges. "Prey size selection in invasive (Hemigrapsus sanguineus and H. takanoi) compared with native (Carcinus maenas) marine crabs." Journal of the Marine Biological Association of the United Kingdom 100, no. 1 (November 20, 2019): 73–77. http://dx.doi.org/10.1017/s0025315419000985.

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AbstractIntroductions of predators can have strong effects on native ecosystems and knowledge of the prey size selection of invasive predators is pivotal to understand their impact on native prey and intraguild competitors. Here, we investigated the prey size selection of two invasive crabs (Hemigrapsus sanguineus and Hemigrapsus takanoi) recently invading European coasts and compared them with native shore crabs (Carcinus maenas) which are known to feed on similar prey species. In laboratory experiments, we offered different size classes of native blue mussels (Mytilus edulis) to different size classes of the crab species in an effort to identify the respective prey size preferences and potential overlap in prey size range of native and invasive crabs. In all three species, the preferred prey size increased with crab size reflecting general predator–prey size relationships. Prey size preference did not differ among the crab species, i.e. crabs showed similar mussel size preference in relation to carapace width. Given that additional morphological measurements showed that both of the invasive crab species have much larger claws relative to their body size compared with the native species, this finding was surprising and may relate to differential claw morphologies or structural strength. These results suggest that the invasive crabs exert predation pressure on the same size classes of native mussels as the native crabs, with potential effects on mussel population dynamics due to the high densities of the invaders. In addition, the overlap in prey size range is likely to result in resource competition between invasive and native crabs.

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Journal articles on the topic 'Prey size'

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