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

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.

1989 ◽  
Vol 46 (11) ◽  
pp. 1977-1985 ◽  
Author(s):  
Mark B. Sandheinrich ◽  
Gary J. Atchison

The effects of four copper concentrations (5 [control], 31, 180, 1710 μg L−1) on bluegill (Lepomis macrochirus) foraging behavior were examined with two separate experiments; one experiment assessing copper effects on the reaction distance of bluegill to two sizes of untreated zooplankton and one assessing copper effects on the functional response of bluegill to untreated (five tests) and treated (five tests) invertebrate prey. Prey used in these experiments were: Daphnia pulex, D. magna (Cladocera), Hyalella azteca (Amphipoda), and two sizes of Enallagma sp. (Zygoptera). Copper had no effect on the reaction distance of fish to zooplankton. There was a significant negative dose-response relationship for consumption rates of all untreated prey but not of treated prey groups. Prey handling time for bluegill capturing treated and untreated prey increased significantly with copper concentration and was the most consistently sensitive parameter measured. Capture efficiency by bluegill, although altered by copper for some prey types, was not as consistent a measure of toxicant stress. This study suggests that mechanistic measures are valuable indicators of toxicant effects on fish feeding behavior and that copper concentrations near the U.S. Environmental Protection Agency water quality criteria (18–28 μ L−1) may alter food consumption and reduce growth of fish in the wild.


1974 ◽  
Vol 31 (9) ◽  
pp. 1531-1536 ◽  
Author(s):  
Earl E. Werner

The relation between fish size, prey size, and handling time was determined for bluegill (Lepomis macrochirus) and green (L. cyanellus) sunfishes with both artificial and natural prey. When scaled by plotting handling time against the ratio of prey size to mouth size, the relation was quite general across fish size and species and is described by a modified exponential equation. Handling time increases [Formula: see text] fold as fish approach satiation. Curves of handling time/unit return define optimal prey size for fish of different size and/or species and illustrate comparative aspects of the breadth of diet for different sized sunfish. Certain life history features of the bluegill are interpreted on the basis of these curves. Optimal prey size occurs at a prey size to mouth size ratio of 0.59 regardless of fish size.


1980 ◽  
Vol 58 (9) ◽  
pp. 1564-1574 ◽  
Author(s):  
J. P. Myers ◽  
S. L. Williams ◽  
F. A. Pitelka

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


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
J L Ward ◽  
V Korn ◽  
A N Auxier ◽  
H L Schoenfuss

Synopsis A variety of environmental estrogens are commonly detected in human-impacted waterways. Although much is known about the effects of these environmental estrogens on the reproductive physiology and behavior of individuals within species, comparatively less is known about how these compounds alter the outcomes of interactions between species. Furthermore, few studies have considered how the effects of contaminants are modulated by natural variation in abiotic factors, such as temperature. To help fill this knowledge gap, we conducted a factorial experiment to examine the independent and combined effects of estrone (E1) and temperature on the outcome of predator–prey interactions between two common North American freshwater fishes, fathead minnows (Pimephales promelas) and bluegill sunfish (Lepomis macrochirus). Larval fathead minnows and adult sunfish were exposed to either a low (mean±standard deviation, 90.1 ± 18 ng/L; n = 16) or high (414 ± 147 ng/L; n = 15) concentration of E1 or to a solvent control for 30 days at one of four natural seasonal temperatures (15°C, 18°C, 21°C, and 24°C) before predation trials were performed. Exposure to E1 was associated with a significant increase in larval predation mortality that was independent of temperature. Across all temperature treatments, approximately 74% of control minnows survived; this survivorship significantly exceeded that of minnows exposed to either concentration of E1 (49% and 53% for minnows exposed to the low and high concentrations, respectively). However, exposure to E1 also impaired the prey-capture success of sunfish, partially mitigating predation pressure on exposed minnows. Overall prey-capture success by sunfish showed an inverted U-shaped distribution with temperature, with maximal prey consumption occurring at 21°C. This study illustrates the vulnerability of organismal interactions to estrogenic pollutants and highlights the need to include food web interactions in assessments of risk.


1986 ◽  
Vol 64 (3) ◽  
pp. 704-713 ◽  
Author(s):  
Eileen Bannon ◽  
Neil H. Ringler

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.


2001 ◽  
Vol 79 (10) ◽  
pp. 1834-1841 ◽  
Author(s):  
Michael T Anderson ◽  
Joseph M Kiesecker ◽  
Douglas P Chivers ◽  
Andrew R Blaustein

Abiotic factors may directly influence community structure by influencing biotic interactions. In aquatic systems, where gape-limited predators are common, abiotic factors that influence organisms' growth rates potentially mediate predator–prey interactions indirectly through effects on prey size. We tested the hypothesis that temperature influences interactions between aquatic size-limited insect predators (Notonecta kirbyi) and their larval anuran prey (Hyla regilla) beyond its indirect effect on prey size. Notonecta kirbyi and H. regilla were raised and tested in predator–prey trials at one of three experimentally maintained temperatures, 9.9, 20.7, or 25.7°C. Temperature strongly influenced anuran growth and predator success; mean tadpole mass over time was positively related to temperature, while the number of prey caught was negatively related. At higher temperatures tadpoles attained greater mass more quickly, allowing them to avoid capture by notonectids. However, the probability of capture is a function of both mass and temperature; temperature was a significant explanatory variable in a logistic regression equation predicting prey capture. For a given prey mass, tadpoles raised in warmer water experienced a higher probability of capture by notonectids. Thus, rather than being static, prey size refugia are influenced directly by abiotic factors, in this case temperature. This suggests that temperature exerts differential effects on notonectid and larval anurans, leading to differences in the probability of prey capture for a given prey mass. Therefore, temperature can influence predator–prey interactions via indirect effects on prey size and direct effects on prey.


2000 ◽  
Vol 48 (1) ◽  
pp. 59 ◽  
Author(s):  
V. W. Framenau ◽  
L. A. Finley ◽  
K. Allan ◽  
M. Love ◽  
D. Shirley ◽  
...  

Multiple prey capture, the behaviour of a predator attacking prey whilst handling a previously caught item, occurs in a variety of spiders that do not build webs. The effects of recent feeding history on the frequency of multiple prey attacks, handling time, ingestion rate, and intercatch intervals were examined experimentally in the wolf spider Lycosa lapidosa McKay. Juvenile spiders were subjected to two different feeding regimes (starvation for 14 and 28 days) and then provided with two different prey types (blowflies, Lucilia cuprina, and crickets, Acheta domestica). These two starvation levels or prey types had little effect on the frequency (75%) of multiple prey attacks. Spiders ingested approximately half the weight of any captured prey, regardless of how many prey items they attacked. At the same time, the handling time per prey item decreased with an increasing number of prey attacked. This indicates a more efficient ingestion rate when more prey are consumed. While the attacking time for the first prey was the same for all treatments, the first intercatch interval was longer for spiders that were starved longer. Chronically starved L. lapidosa appear to secure a previously caught item rather than optimise their capture rate by attacking further available prey.


Ethology ◽  
2007 ◽  
Vol 113 (9) ◽  
pp. 856-861 ◽  
Author(s):  
Andréa L.T. Souza ◽  
Marcelo O. Gonzaga ◽  
João Vasconcellos-Neto

Behaviour ◽  
2010 ◽  
Vol 147 (8) ◽  
pp. 933-951 ◽  
Author(s):  

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


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