scholarly journals Single target acuity in the common sunfish (Lepomis gibbosus)

2021 ◽  
Author(s):  
Caroline Spratte ◽  
Laura-Marie Sandow ◽  
Julia S. Schnermann ◽  
Frederike D. Hanke
Keyword(s):  
Reproductive Behavior ◽  
Distance Measures ◽  
Behavioral Experiment ◽  
Lepomis Gibbosus ◽  
Biologically Relevant ◽  
Behavioral Observations ◽  
Reactive Distance ◽  
Single Target ◽  
The Common ◽  
Prey Items

Vision is considered to contribute to foraging, territorial, and reproductive behavior in sunfish. In these contexts, sunfish need to perceive single targets, such as prey items or body markings from either conspecifics or individuals of other sunfish species, from some distances. We determined the single target acuity of six common sunfish in a behavioral experiment to assess whether the visual abilities of sunfish correspond with behavioral observations or reactive distance measures and thus to assess the limits of vision regarding the mentioned behaviors. Single target acuity for full-contrast single targets amounted to 0.17 (0.13 - 0.32) deg. When contrast was reduced to Weber contrasts of 0.67 and 0.41, single target acuity dropped to 0.34 (0.31 - 0.37) deg, and finally to 0.42 (0.34 - 0.54) deg. Single target acuity would thus allow common sunfish to perceive biologically relevant stimuli at reasonable distances even when contrast is reduced.

scholarly journals Evidence of Predation on Nestling Birds by Eastern Gartersnakes (Thamnophis sirtalis sirtalis)

2016 ◽  
Vol 130 (2) ◽  
pp. 146 ◽  
Author(s):  
William D. Halliday
Keyword(s):  
Natural History ◽  
Food Choice ◽  
Prey Availability ◽  
Prey Preference ◽  
Thamnophis Sirtalis ◽  
Space And Time ◽  
History Of ◽  
The Common ◽  
Prey Items

Diet is an important aspect of the natural history of all animals, but diet can vary through space and time because of variations in prey availability. The diet of the Common Gartersnake (Thamnophis sirtalis) consists mainly of earthworms and frogs, but other prey items might be important when they are locally abundant. I report an observation of a female Eastern Gartersnake (Thamnophis sirtalis sirtalis) regurgitating 2 nestling birds in Ottawa, Ontario, Canada. Birds are seldom present in the diet of the Common Gartersnake. This rare food choice highlights the opportunistic nature of foraging by adult Common Gartersnakes and, further, demonstrates that diet depends not only on prey preference, but also on prey availability.

Novel Glucose Biosensor Based on the Microcantilever

2003 ◽  
Vol 776 ◽  
Author(s):  
Jianhong Pei ◽  
Fang Tian ◽  
Thomas Thundat
Keyword(s):  
Glucose Biosensor ◽  
Enzyme Specificity ◽  
Biologically Relevant ◽  
Novel Technique ◽  
Novel Technology ◽  
Physical Chemical ◽  
Wide Range ◽  
Cantilever Surface ◽  
The Common ◽  
Detection Schemes

AbstractWe report a novel technique for micromechanical detection of biologically relevant glucose by immobilization of glucose oxidase (GOx) onto a microcantilever surface. Microfabricated cantilevers have recently attracted considerable interest in the development of a wide range of novel physical, chemical, and biological sensors. This paper describes the combination of this novel technology with enzyme specificity to construct a highly selective glucose biosensor. The enzyme-functionalized microcantilever undergoes bending due to a change in surface stress induced by the reaction between glucose and the GOx immobilized on the cantilever surface. The common interferents for glucose detection in other detection schemes have been tested and have shown no effect on the measurement of blood glucose level by this technique.

Prey choice of Tengmalm's owls (Aegolius funereus funereus): preference for substandard individuals?

1996 ◽  
Vol 74 (5) ◽  
pp. 816-823 ◽  
Author(s):  
Vesa Koivunen ◽  
Erkki Korpimäki ◽  
Harri Hakkarainen ◽  
Kai Norrdahl
Keyword(s):  
Common Shrew ◽  
Common Vole ◽  
Clethrionomys Glareolus ◽  
Prey Choice ◽  
Aegolius Funereus ◽  
Nest Boxes ◽  
Bank Voles ◽  
The Common ◽  
Common Voles ◽  
Prey Items

Errington proposed that predators mainly kill substandard prey, because dominant individuals force subordinate ones into poor habitats, where the predation risk is higher. We studied the prey choice of breeding male Tengmalm's owls (Aegolius funereus funereus) in 1992, when vole densities crashed. We trapped small mammals in the main habitat types in 21 owl territories, and simultaneously identified prey items cached by the same owls in their nest boxes. The main prey of owls in western Finland are the common vole (Microtus epiroticus), field vole (M. agrestis), bank vole (Clethrionomys glareolus), and common shrew (Sorex araneus). Common voles were the preferred prey of owls, followed by field voles, bank voles, and common shrews. Prey captured by owls tended to be lighter and smaller than those available in the field. This tendency was significant for field voles and common shrews. Field voles, common voles, and female common shrews captured by owls tended to have more internal fat than those available in the field. This tendency was significant for male field voles and female common shrews. Owls appeared to choose small individuals of some, but not all, prey species, and that these prey items were not in poor physiological condition.

Some little-known and new protozoan parasites of fish from Lake Sasajewun, Algonquin Park, Ontario

1989 ◽  
Vol 67 (6) ◽  
pp. 1372-1379 ◽  
Author(s):  
Jiří Lom ◽  
Sherwin S. Desser ◽  
Iva Dyková
Keyword(s):  
Tissue Specificity ◽  
Polar Filament ◽  
Lepomis Gibbosus ◽  
Renal Tubules ◽  
Protozoan Parasites ◽  
Sporocyst Residuum ◽  
Semotilus Atromaculatus ◽  
Ictalurus Nebulosus ◽  
The Common ◽  
Creek Chub

One hundred and twenty-six fish of eight species, taken from Lake Sasajewun, Ontario, were examined for protozoan parasites. Detailed descriptions are given for Sphaerospora diminuta Li and Desser from the pumpkinseed, Lepomis gibbosus, and for Goussia degiustii Molnar and Fernando from the common shiner, Notropis cornutus. Oocysts of G. degiustii are pleomorphic and exhibit low tissue specificity. Goussia freemani Molnar and Fernando from the kidney of N. cornutus is tentatively synonymized with Goussia leucisci Shulman and Zaika. Two new species of Sphaerospora are described: Sphaerospora paulini n.sp. from the renal tubules of creek chub, Semotilus atromaculatus, with spherical spores 8.1 (8.0–8.5) μm in diameter, containing ovoid polar capsules 2.8 (2.5–3.4) × 2.6 (2.5–3.0) μm, and polar filament with 4–5 coils; and Sphaerospora hankai n.sp. from the renal tubules of the brown bullhead, Ictalurus nebulosus, with subspherical spores 6.1 (5.4–6.6) × 6.0 (5.4–6.5) μm, unequal subspherical polar capsules (larger, 2.8 (2.5–3.1) × 2.7 (2.3–2.9) μm; smaller, 2.4 (2.1–2.6) × 2.0 (1.9–2.2) μm), and polar filament with 4–5 coils in larger capsule, 3–4 coils in smaller capsule. Eimeria patersoni n.sp. is described from the kidney, spleen, and liver of L. gibbosus. Oocysts are subspherical (11.9 × 10.6), sporocysts ellipsoidal (10.4 (9.9–11.2) × 3.5 (2.6–4.0) μm), and sporozoites stubby (3.6 × 2.0 μm); sporocyst residuum has 1–3 large granules.

The diet of the Common Kestrel in the urban environment of the city of Nitra

2008 ◽  
Vol 2 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Lucia Kečkéšová ◽  
Michal Noga
Keyword(s):  
Urban Environment ◽  
House Mouse ◽  
Common Vole ◽  
Microtus Arvalis ◽  
Nesting Sites ◽  
The Common ◽  
Prey Remains ◽  
The City ◽  
Prey Items

The diet of the Common Kestrel in the urban environment of the city of Nitra The diet of the urban Common Kestrel population was studied in Nitra during 2003-2005. Totally, 671 prey items were identified by the analysis of pellets and prey remains collected under the nesting sites. Insect, mainly represented by order Coleoptera, was found to be the most abundant prey. Regarding biomass, the Common Vole (Microtus arvalis) was predominated. In comparison with other articles published, the studied sample was rather rich in the Lesser White-toothed Shrew (Crocidura suaveolens) and the House Mouse (Mus cf. musculus).

scholarly journals Outliers in Semi-Parametric Estimation of Treatment Effects

Econometrics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 19
Author(s):  
Gustavo Canavire-Bacarreza ◽  
Luis Castro Peñarrieta ◽  
Darwin Ugarte Ontiveros
Keyword(s):  
Parametric Estimation ◽  
The Other ◽  
Distance Measures ◽  
Parametric Methods ◽  
Support Condition ◽  
Leverage Points ◽  
Leverage Point ◽  
Common Support ◽  
Multivariate Location ◽  
The Common

Outliers can be particularly hard to detect, creating bias and inconsistency in the semi-parametric estimates. In this paper, we use Monte Carlo simulations to demonstrate that semi-parametric methods, such as matching, are biased in the presence of outliers. Bad and good leverage point outliers are considered. Bias arises in the case of bad leverage points because they completely change the distribution of the metrics used to define counterfactuals; good leverage points, on the other hand, increase the chance of breaking the common support condition and distort the balance of the covariates, which may push practitioners to misspecify the propensity score or the distance measures. We provide some clues to identify and correct for the effects of outliers following a reweighting strategy in the spirit of the Stahel-Donoho (SD) multivariate estimator of scale and location, and the S-estimator of multivariate location (Smultiv). An application of this strategy to experimental data is also implemented.

scholarly journals Diet composition, body condition and sexual size dimorphism of the common African toad (Amietophrynus regularis) in urban and agricultural landscape

2021 ◽  
Author(s):  
Benjamin Yeboah Ofori ◽  
John Bosu Mensah ◽  
Roger Sigismund Anderson ◽  
Daniel Korley Attuquayefio
Keyword(s):  
Body Condition ◽  
Diet Composition ◽  
Sexual Size Dimorphism ◽  
Agricultural Landscape ◽  
Individual Characteristics ◽  
Generalist Predator ◽  
Natural Habitats ◽  
Size Dimorphism ◽  
The Common ◽  
Prey Items

AbstractLand use and land cover change (LULCC) are major drivers of global biodiversity loss. The conversion of natural habitats into human-modified landscapes poses novel and multifaceted environmental stressors to organisms, influencing their ecology, physiology, life history and fitness. Although the effects of LULCC have been studied extensively at the community level, there is scant information about its effect on population and individual characteristics. We assessed the diet composition, body condition, and sexual size dimorphism of the common African toad (Amietophrynus regularis) in urban and agricultural landscape. Diet composition was evaluated using gut content analysis, while body condition was measured using residual mass index. Overall, 935 prey items comprising six classes, at least 18 orders and 31 families were obtained from toads. This broad dietary niche suggested that Amietophrynus regularis is a generalist predator. The family Formicidae was the most consumed prey item, with a frequency of occurrence above 80% at both sites. We found no sex- or habitat-biased dietary partitioning in the toads. A statistically significant positive correlation existed between snout-vent-length (SVL) and diversity of prey items (Pearson’s correlation r = 0.999, p ≤ 0.0001) for toads from farmland, which also had better body conditions. The toads showed female-biased sexual size dimorphism, but males had longer tibio-fibula, radio-ulna, foot, and distal fore limbs. This study is probably the first to assess the diet composition, body condition and sexual size dimorphism of Amietophrynus regularis simultaneously. The ecological, evolutionary and conservation implications of our findings are discussed.

scholarly journals Aspects of the reproductive ecology of Trachycephalus cunauaru (Anura: Hylidae) in the southern Amazon

2021 ◽  
Vol 51 (1) ◽  
pp. 34-41
Author(s):  
Janaina da Costa de NORONHA ◽  
Cynthia P. A. PRADO ◽  
Jean-Marc HERO ◽  
Guy CASTLEY ◽  
Domingos de Jesus RODRIGUES
Keyword(s):  
Reproductive Behavior ◽  
Digital Camera ◽  
Environmental Parameters ◽  
Camera Traps ◽  
Chemical Characteristics ◽  
Mato Grosso ◽  
Behavioral Observations ◽  
History Of ◽  
Physical And Chemical ◽  
First Time

ABSTRACT Trachycephalus cunauaru is an Amazonian hylid that uses phytotelmata to reproduce. There is relatively little information about the species, mainly due to the difficulty of accessing their reproductive sites. In this study, we gathered data on the ecology and natural history of T. cunauaru in the southern Amazon, in the state of Mato Grosso, Brazil. In addition to natural phytotelmata, we used buckets installed at a height of 10 m as artificial phytotelmata. We compared physical and chemical characteristics, as well as the presence of tadpoles between natural and artificial phytotelmata. We also collected data on the reproductive behavior of the species through the use of camera traps. We recorded a density of 14.1 reproductive sites per km². Environmental parameters differed significantly between artificial and natural phytotelmata. In artificial sites, the presence of tadpoles was directly related to trees with a larger diameter. We registered oophagy for the first time for the species and observed that males can use more than one phytotelm. We also recorded the presence of snakes within the reproductive sites. We determined that artificial sites and digital camera traps are a satisfactory alternative for behavioral observations of T. cunauaru and possibly for other species with a similar habit.

scholarly journals Subjectivism as an unavoidable feature of ecological statistics

2014 ◽  
Vol 37 (2) ◽  
pp. 141-143
Author(s):  
A. Martínez-Abrain ◽  
◽  
D. Conesa ◽  
A. Forte ◽  
◽  
...  
Keyword(s):  
Biological Sciences ◽  
Parameter Estimation ◽  
Model Selection ◽  
Statistical Inference ◽  
Prior Information ◽  
A Priori ◽  
Model Specification ◽  
Biologically Relevant ◽  
The Common ◽  
Ecological Statistics

We approach here the handling of previous information when performing statistical inference in ecology, both when dealing with model specification and selection, and when dealing with parameter estimation. We compare the perspectives of this problem from the frequentist and Bayesian schools, including objective and subjective Bayesians. We show that the issue of making use of previous information and making a priori decisions is not only a reality for Bayesians but also for frequentists. However, the latter tend to overlook this because of the common difficulty of having previous information available on the magnitude of the effect that is thought to be biologically relevant. This prior information should be fed into a priori power tests when looking for the necessary sample sizes to couple statistical and biological significances. Ecologists should make a greater effort to make use of available prior information because this is their most legitimate contribution to the inferential process. Parameter estimation and model selection would benefit if this was done, allowing a more reliable accumulation of knowledge, and hence progress, in the biological sciences.

scholarly journals The role of feedback in risk-sensitivity

2020 ◽  
Author(s):  
Ohad Dan ◽  
Yonatan Loewenstein
Keyword(s):  
Risk Aversion ◽  
Behavioral Experiment ◽  
Risk Sensitivity ◽  
Risk Seeking ◽  
Specific Effects ◽  
Partial Feedback ◽  
The Common ◽  
Feedback Method ◽  
Human Participants

Over the last century, myriad versions of the bandit task were used to study operant conditioning in humans and other animals. However, the overwhelming majority of these variations utilized one of two types of feedbacks, partial and full feedback, revealing to participants the single outcome of the chosen alternative or the outcomes of all alternatives respectively. While ecologically relevant, when restricting the feedback method to these two methods alone, observed behavioral phenomena could potentially be confounded with specific effects that the feedback method itself might induce, for example attitude towards risk. Here we introduce a new form of feedback. In a 2-armed bandit task, the reverse feedback reveals to participants only the outcome of the unchosen alternative. In a behavioral experiment, human participants were incentivized to maximize their per-trial reward while exploring the reward-distribution associated with two alternatives. Randomly assigning participants to a specific type of feedback, we find that participants in the partial and reverse feedback condition demonstrated behavior consistent with risk aversion and risk seeking. This result is intriguing for two reasons. First, in gains-domain, humans are considered risk-averse and it is hence surprising to observe a robust demonstration of risk seeking. Second, We present risk-sensitivity as a casual outcome of the utilized feedback. Since in most ecological and lab environments humans utilize the partial feedback and demonstrate risk-aversion, our finding sheds new light on the common perception of risk-sensitivity as an inherent, rather than induced, characteristic. Utilizing a simple reinforcement learning model, we explain the emergent risk preference as an outcome of learning in the specific environment we use. We present the relation of our paradigm to prospect theory, relate our finding to existing literature, and discuss the new light our novel feedback-mechanisms shed on conclusions drawn from previous paradigms.

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