Prey capture success and chick diet of Damara ternsSterna balaenarumin Namibia

2011 ◽  
Vol 33 (2) ◽  
pp. 247-254 ◽  
Author(s):  
J Braby ◽  
L G Underhill ◽  
R E Simmons
Keyword(s):  
Prey Capture ◽  
Capture Success ◽  
Chick Diet

scholarly journals Temperature and Estrogen Alter Predator–Prey Interactions between Fish Species

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
J L Ward ◽  
V Korn ◽  
A N Auxier ◽  
H L Schoenfuss
Keyword(s):  
Prey Capture ◽  
Abiotic Factors ◽  
Pimephales Promelas ◽  
Lepomis Macrochirus ◽  
Environmental Estrogens ◽  
Fathead Minnows ◽  
Predator Prey ◽  
Food Web Interactions ◽  
Capture Success ◽  
High Concentrations

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.

scholarly journals How within-group behavioural variation and task efficiency enhance fitness in a social group

2010 ◽  
Vol 278 (1709) ◽  
pp. 1209-1215 ◽  
Author(s):  
Jonathan N. Pruitt ◽  
Susan E. Riechert
Keyword(s):  
Prey Capture ◽  
Common Garden ◽  
Division Of Labour ◽  
Large Prey ◽  
Task Specialization ◽  
Capture Success ◽  
Social Phenotype ◽  
Individual Task ◽  
Task Efficiency

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus , colony members exhibit a behavioural polymorphism; females either exhibit an aggressive ‘asocial’ or docile ‘social’ phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

Echolocation behaviour and prey-capture success in foraging bats: laboratory and field experiments on Myotis daubentonii

1999 ◽  
Vol 202 (13) ◽  
pp. 1793-1801 ◽  
Author(s):  
A.R. Britton ◽  
G. Jones
Keyword(s):  
Field Experiments ◽  
Prey Capture ◽  
Prey Size ◽  
Interpulse Interval ◽  
Terminal Phase ◽  
Silent Interval ◽  
Capture Success ◽  
Myotis Daubentonii ◽  
The Mean ◽  
Approach Phase

During prey-capture attempts, many echolocating bats emit a ‘terminal buzz’, when pulse repetition rate is increased and pulse duration and interpulse interval are shortened. The buzz is followed by a silent interval (the post-buzz pause). We investigated whether variation in the structure of the terminal buzz, and the calls and silent periods following it, may provide information about whether the capture attempt was successful and about the size of prey detected - detail that is valuable in studies of habitat use and energetics. We studied the trawling bat Myotis daubentonii. The time between the first call of the approach phase and the end of the terminal phase was not related to prey size in the laboratory. The last portion of the terminal buzz (buzz II) was shortened or omitted during aborted capture attempts. Both in the laboratory and in the field, the mean interpulse interval immediately after the terminal buzz (post-buzz interpulse interval) was longer in successful captures than in unsuccessful attempts. In the laboratory, the post-buzz pause was longer after successful captures than for unsuccessful attempts, and the minimum frequency of the first search-phase call emitted after the buzz (Fmin) was higher than that of the last such call prior to the buzz. These effects were not apparent in field data. Both in the laboratory (85%) and in the field (74%), significant discrimination between successful and unsuccessful capture attempts was possible when the duration of the post-buzz pause, post-buzz interpulse interval and Fmin were entered into a discriminant analysis. Thus, variation in the echolocation calls of bats during prey-capture attempts can reveal substantial information about capture success and prey size.

scholarly journals Modelled three-dimensional suction accuracy predicts prey capture success in three species of centrarchid fishes

2014 ◽  
Vol 11 (95) ◽  
pp. 20140223 ◽  
Author(s):  
Emily A. Kane ◽  
Timothy E. Higham
Keyword(s):  
Prey Capture ◽  
Micropterus Salmoides ◽  
Three Dimensional ◽  
Performance Measure ◽  
Natural Conditions ◽  
Capture Success ◽  
Lower Accuracy ◽  
Ram Speed ◽  
Centrarchid Fishes

Prey capture is critical for survival, and differences in correctly positioning and timing a strike (accuracy) are likely related to variation in capture success. However, an ability to quantify accuracy under natural conditions, particularly for fishes, is lacking. We developed a predictive model of suction hydrodynamics and applied it to natural behaviours using three-dimensional kinematics of three centrarchid fishes capturing evasive and non-evasive prey. A spheroid ingested volume of water (IVW) with dimensions predicted by peak gape and ram speed was verified with known hydrodynamics for two species. Differences in capture success occurred primarily with evasive prey (64–96% success). Micropterus salmoides had the greatest ram and gape when capturing evasive prey, resulting in the largest and most elongate IVW. Accuracy predicted capture success, although other factors may also be important. The lower accuracy previously observed in M. salmoides was not replicated, but this is likely due to more natural conditions in our study. Additionally, we discuss the role of modulation and integrated behaviours in shaping the IVW and determining accuracy. With our model, accuracy is a more accessible performance measure for suction-feeding fishes, which can be used to explore macroevolutionary patterns of prey capture evolution.

scholarly journals Testing Darwin’s hypothesis about the most wonderful plant in the world: The Venus flytrap’s marginal spikes are a ‘horrid prison’ for moderate-sized insect prey

2018 ◽  
Author(s):  
Alexander L. Davis ◽  
Matthew H. Babb ◽  
Brandon T. Lee ◽  
Christopher H. Martin
Keyword(s):  
Prey Capture ◽  
Feeding Strategy ◽  
Adaptive Landscape ◽  
Large Prey ◽  
Capture Success ◽  
Dionaea Muscipula ◽  
Lab Experiments ◽  
Morphological Adaptations ◽  
The World ◽  
Laboratory Results

AbstractBotanical carnivory is a novel feeding strategy associated with numerous physiological and morphological adaptations. However, the benefits of these novel carnivorous traits are rarely tested. Here, we used field observations and lab experiments to test the prey capture function of the marginal spikes on snap traps of the Venus flytrap (Dionaea muscipula). Our field and laboratory results suggested surprisingly inefficient capture success: fewer than 1 in 4 prey encounters led to prey capture. Removing the marginal spikes decreased the rate of prey capture success for moderate-sized cricket prey by 90%, but this effect disappeared for larger prey. The nonlinear benefit of spikes suggests that they provide a better cage for capturing more abundant insects of moderate and small sizes, but may also provide a foothold for rare large prey to escape. Our observations support Darwin’s hypothesis that the marginal spikes form a ‘horrid prison’ that increases prey capture success for moderate-sized prey, but the decreasing benefit for larger prey is unexpected and previously undocumented. Thus, we find surprising complexity in the adaptive landscape for one of the most wonderful evolutionary innovations among all plants. These findings further enrich our understanding of the evolution and diversification of novel trap morphology in carnivorous plants.

scholarly journals Fenestration: a window of opportunity for carnivorous plants

2014 ◽  
Vol 10 (4) ◽  
pp. 20140134 ◽  
Author(s):  
H. Martin Schaefer ◽  
Graeme D. Ruxton
Keyword(s):  
Retention Time ◽  
Prey Capture ◽  
Animal Communication ◽  
Carnivorous Plants ◽  
Window Of Opportunity ◽  
Aggressive Mimicry ◽  
Capture Success ◽  
Need To Evaluate ◽  
Alternative Hypotheses ◽  
Transparent Windows

A long-standing but controversial hypothesis assumes that carnivorous plants employ aggressive mimicry to increase their prey capture success. A possible mechanism is that pitcher plants use aggressive mimicry to deceive prey about the location of the pitcher's exit. Specifically, species from unrelated families sport fenestration, i.e. transparent windows on the upper surfaces of pitchers which might function to mimic the exit of the pitcher. This hypothesis has not been evaluated against alternative hypotheses predicting that fenestration functions to attract insects from afar. By manipulating fenestration, we show that it does not increase the number of Drosophila flies or of two ant species entering pitchers in Sarracenia minor nor their retention time or a pitcher's capture success. However, fenestration increased the number of Drosophila flies alighting on the pitcher compared with pitchers of the same plant without fenestration. We thus suggest that fenestration in S. minor is not an example of aggressive mimicry but rather functions in long-range attraction of prey. We highlight the need to evaluate aggressive mimicry relative to alternative concepts of plant–animal communication.

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