Aggregations of newly metamorphosed Bufo americanus: tests of two hypotheses

1993 ◽  
Vol 71 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Joel T. Heinen
Keyword(s):  
Weight Loss ◽  
High Risk ◽  
Predation Risk ◽  
Bufo Americanus ◽  
Anuran Amphibians ◽  
Risk Of Predation

Newly metamorphosed anuran amphibians of several species have been observed to form very dense aggregations around the peripheries of breeding ponds; in some cases, the animals will literally pile on conspecifics. Two hypotheses used to explain the behavior were tested in several experimental situations: that juvenile anurans aggregate as a response to (i) predation risk or (ii) desiccation. Two experimental setups were used to test the first hypothesis. There was no tendency for nonphysiologically stressed juvenile Bufo americanus to group on a relatively high-risk substrate or in the presence of a preformed group, with or without a predator present. The results of two additional experiments showed that these animals aggregated as a response to desiccation and that animals desiccated alone suffered greater weight loss and mortality than those desiccated in groups. Thus, the results strongly support the hypothesis that these young anurans aggregate in response to the risk of desiccation, not to the risk of predation.

scholarly journals Flirting with danger: predation risk interacts with male condition to influence sexual display

2019 ◽  
Vol 30 (5) ◽  
pp. 1265-1272
Author(s):  
Pedro Z de Moraes ◽  
Pedro Diniz ◽  
Esteban Fernandez-Juricic ◽  
Regina H Macedo
Keyword(s):  
High Risk ◽  
Predation Risk ◽  
Video Recording ◽  
Reproductive Value ◽  
Male Response ◽  
Residual Reproductive Value ◽  
Display Behavior ◽  
Sexual Display ◽  
Male Condition ◽  
Risk Of Predation

AbstractSexual signaling coevolves with the sensory systems of intended receivers; however, predators may be unintended receivers of sexual signals. Conspicuous aerial displays in some species may place males at high risk of predation from eavesdropping predators. There are three different hypotheses to explain how signaling males can deal with increased predation risk: (1) males invest in survival by decreasing signal conspicuousness; (2) males invest in reproduction by increasing signal conspicuousness; and (3) male response is condition-dependent according to his residual reproductive value. Here, we used blue-black grassquits (Volatinia jacarina) to test these hypotheses, asking whether males modify leap displays under different levels of predation risk. Grassquit males develop an iridescent nuptial plumage and spend considerable time emitting a multimodal signal: while leaping from a perch, males clap their wings above their heads and emit a high-pitched short song. We exposed males to predator and nonpredator playbacks while video recording their displays. We found interactions between predation risk and 2 male condition variables (ectoparasite infestation and proportion of nuptial plumage coverage) that influenced display behavior. Less parasitized males and those with higher proportion of nuptial plumage showed no change in display behavior, while more parasitized males and those with lower proportion of nuptial plumage increased the vigor of displays under predation risk. In other words, males with low residual reproductive value increased reproductive effort when there was a high risk of extrinsic death. Our study provides some empirical support for the terminal investment hypothesis.

scholarly journals Silent katydid females are at higher risk of bat predation than acoustically signalling katydid males

2015 ◽  
Vol 282 (1798) ◽  
pp. 20142319 ◽  
Author(s):  
Hanumanthan Raghuram ◽  
Rittik Deb ◽  
Diptarup Nandi ◽  
Rohini Balakrishnan
Keyword(s):  
High Risk ◽  
Predation Risk ◽  
Acoustic Signals ◽  
Diet Analysis ◽  
Playback Experiments ◽  
Long Distance ◽  
Mate Finding ◽  
Risk Of Predation ◽  
Males And Females ◽  
Behavioural Experiments

Males that produce conspicuous mate attraction signals are often at high risk of predation from eavesdropping predators. Females of such species typically search for signalling males and their higher motility may also place them at risk. The relative predation risk faced by males and females in the context of mate-finding using long-distance signals has rarely been investigated. In this study, we show, using a combination of diet analysis and behavioural experiments, that katydid females, who do not produce acoustic signals, are at higher risk of predation from a major bat predator, Megaderma spasma , than calling males. Female katydids were represented in much higher numbers than males in the culled remains beneath roosts of M. spasma . Playback experiments using katydid calls revealed that male calls were approached in only about one-third of the trials overall, whereas tethered, flying katydids were always approached and attacked. Our results question the idea that necessary costs of mate-finding, including risk of predation, are higher in signalling males than in searching females.

scholarly journals FRI0443 CLINICAL CHARACTERISTICS AND RELATED FACTORS OF COMMON RHEUMATIC DISEASES COMPLICATED WITH TUBERCULOSIS INFECTION

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 819.1-819
Author(s):  
L. Long ◽  
G. Tang ◽  
Y. Han ◽  
Q. Peng ◽  
J. Liu ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Weight Loss ◽  
Risk Factor ◽  
High Risk ◽  
Rheumatic Diseases ◽  
Clinical Characteristics ◽  
Control Group ◽  
Average Dose ◽  
Systemic Lupus ◽  
Infection Group

Background:Rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and syndrome(SS) are common rheumatic diseases with high incidence. Patients with those rheumatic diseases are at high risk of tuberculosis (TB) infection. However, manifestations can be atypical and easily confused with those of rheumatic disease itself. For those patients, diagnosis is usually much more difficult and further make treatment delayed. Sometimes it may lead to mistreatment. Therefore, it is important to recognize the clinical characteristics of those patients.Objectives:To explore the clinical characteristics and high risk factors of common systemic rheumatism complicated with tuberculosis infection.Methods:A total of 3,906 cases of RA, SLE, and SS common systemic rheumatism diagnosed in the People’s Hospital of Sichuan Province from January 2007 to January 2017 were collected with carefully exclusion with other infectious diseases and neoplastic disease. One hundred and five patients with TB were included as infection group, including 42 cases of RA, 41 cases of SLE, and 22 cases of SS. In the control group, 84 patients with RA, 82 patients with SLE, and 44 patients with SS were randomly selected from the corresponding rheumatoid non-infected patients hospitalized during the same period.Results:Fever was the most common symptom among 42 cases of RA, 41 cases of SLE, and 22 cases of SS with TB, accounting for 83.3%, 92.7%, and 68.2%, respectively. Cough, weight loss or fatigue was less common. For 41 cases of SLE and 22 cases of SS with TB, the proportion of pulmonary was 46.3%, 59.01%, respectively.In TB infection group, 27 cases of RA, 21 cases of SLE, and 13 cases of SS with TB had two or more chest CT findings, accounting for 59%, 57%, 62%, respectively. Lesions located in the posterior or posterior segment which TB usually affected were 9 cases(33.3%),9cases(42.9%),6cases(27.2%),respectively.The daily average dose of hormones within 1 year in TB infection group was higher than that in the control group (P<0.05). For SLE patients, lower counts of CD4+TL were found in TB infection group (P<0.05), while no such differences were found in RA and SS group.Conclusion:Patients with RA who have TB infection are mainly pulmonary TB. For SLE and SS patients, the chance of pulmonary tuberculosis and extra-pulmonary tuberculosis is similar.Symptoms of RA, SLE, SS with TB, such as fever, cough, weight loss, fatigue, are similar with the primary disease or other infection. Chest imaging is diversity. It is difficult to diagnose.Daily average dose of hormone within one year may be a common risk factor for RA, SLE and SS patients with TB. Decreased CD4+TL may also be a risk factor for SLE patients with TB.References:[1]Cantini F, Nannini C, Niccoli L, et al. Risk of Tuberculosis Reactivation in Patients with Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis Receiving Non-Anti-TNF-Targeted Biologics[J]. Mediators of Inflammation, 2017, 2017(6):1-15.[2]Ruangnapa K, Dissaneewate P, Vachvanichsanong P. Tuberculosis in SLE patients: rare diagnosis, risky treatment.[J]. Clinical & Experimental Medicine, 2015, 15(3):429-432.[3]Manuela D F, Bruno L, Martina S, et al. Lung Infections in Systemic Rheumatic Disease: Focus on Opportunistic Infections[J]. International Journal of Molecular Sciences, 2017, 18(2):293-315.[4]Disseminated tuberculosis masquerading as a presentation of systemic lupus erythematosus.Li JC, Fong W, Wijaya L, Leung YY.Int J Rheum Dis. 2017 Oct 2. doi: 10.1111/1756-185X.13195.[5]Handa R, Upadhyaya S, Kapoor S, et al. Tuberculosis and biologics in rheumatology: India – A special situation[J]. International Journal of Rheumatic Diseases, 2017, 51(2):115.Disclosure of Interests:None declared

Do changes in reef habitats influence relative predation risk on the juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875)?

Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs
Keyword(s):  
Predation Risk ◽  
Spatial Scales ◽  
Spiny Lobster ◽  
Habitat Type ◽  
Small Spatial Scale ◽  
Important Species ◽  
Early Juvenile ◽  
Risk Of Predation ◽  
Jasus Edwardsii ◽  
Commercially Important

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.

Behavioural responses of voles to simulated risk of predation by a native and an alien mustelid: an odour manipulation experiment

2010 ◽  
Vol 37 (4) ◽  
pp. 273 ◽  
Author(s):  
Karen Fey ◽  
Peter B. Banks ◽  
Hannu Ylönen ◽  
Erkki Korpimäki
Keyword(s):  
Baltic Sea ◽  
Predation Risk ◽  
Myodes Glareolus ◽  
The Baltic Sea ◽  
Short Term ◽  
Behavioural Responses ◽  
Alien Predator ◽  
Risk Of Predation ◽  
The Baltic ◽  
The Impact

Context. Potential mammalian prey commonly use the odours of their co-evolved predators to manage their risks of predation. But when the risk comes from an unknown source of predation, odours might not be perceived as dangerous, and anti-predator responses may fail, except possibly if the alien predator is of the same archetype as a native predator. Aims. In the present study we examined anti-predator behavioural responses of voles from the outer archipelagos of the Baltic Sea, south-western Finland, where they have had no resident mammalian predators in recent history. Methods. We investigated responses of field voles (Microtus agrestis) to odours of native least weasels (Mustela nivalis) and a recently invading alien predator, the American mink (Mustela vison), in laboratory. We also studied the short-term responses of free-ranging field voles and bank voles (Myodes glareolus) to simulated predation risk by alien mink on small islands in the outer archipelago of the Baltic Sea. Key results. In the laboratory, voles avoided odour cues of native weasel but not of alien mink. It is possible that the response to mink is a context dependent learned response which could not be induced in the laboratory, whereas the response to weasel is innate. In the field, however, voles reduced activity during their normal peak-activity times at night as a response to simulated alien-mink predation risk. No other shifts in space use or activity in safer microhabitats or denser vegetation were apparent. Conclusions. Voles appeared to recognise alien minks as predators from their odours in the wild. However, reduction in activity is likely to be only a short-term immediate response to mink presence, which is augmented by longer-term strategies of habitat shift. Because alien mink still strongly suppresses vole dynamics despite these anti-predator responses, we suggest that behavioural naiveté may be the primary factor in the impact of an alien predator on native prey. Implications. Prey naiveté has long been considered as the root cause of the devastating impacts of alien predators, whereby native prey simply fail to recognise and respond to the novel predation risk. Our results reveal a more complex form of naiveté whereby native prey appeared to recognise alien predators as a threat but their response is ultimately inadequate. Thus, recognition alone is unlikely to afford protection for native prey from alien-predator impacts. Thus, management strategies that, for example, train prey in recognition of novel threats must induce effective responses if they are expected to succeed.

scholarly journals High-risk alcohol use after weight loss surgery

2014 ◽  
Vol 10 (3) ◽  
pp. 508-513 ◽  
Author(s):  
Christina C. Wee ◽  
Kenneth J. Mukamal ◽  
Karen W. Huskey ◽  
Roger B. Davis ◽  
Mary Ellen Colten ◽  
...  
Keyword(s):  
Weight Loss ◽  
High Risk ◽  
Alcohol Use ◽  
Weight Loss Surgery

scholarly journals Predation Risk by Gastronomic Boom - Case Peru

2018 ◽  
Vol 11 (1) ◽  
pp. 100-103
Author(s):  
Aldo Alvarez-Risco ◽  
Jaime Delgado-Zegarra ◽  
Jaime A. Yáñez ◽  
Santiago Diaz-Risco ◽  
Shyla Del-Aguila-Arcentales
Keyword(s):  
Natural Resources ◽  
Predation Risk ◽  
Environmental Sustainability ◽  
Natural Sources ◽  
Risk Of Predation ◽  
Significant Damage

Abstract The growth of tourism to Peru and the gastronomic boom with millions of people looking to taste Peruvian food is resulting in a risk of predation of natural sources necessary to make these dishes. The focus in only obtaining these ingredients can generate significant damage to the Peruvian biodiversity, so stakeholders need to develop strategies to avoid predation due to the gastronomic boom. Citizens and visitors need to play a role in protecting the natural resources and contributing to environmental sustainability.

scholarly journals Weight Loss Predicts Inferior Outcome in Polycythemia Vera Patients

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 22-23
Author(s):  
Albert Jang ◽  
Hussein Hamad ◽  
Sarvari Venkata Yellapragada ◽  
Iberia R. Sosa ◽  
Gustavo A. Rivero
Keyword(s):  
Weight Loss ◽  
High Risk ◽  
Blood Cell ◽  
Polycythemia Vera ◽  
Board Of Directors ◽  
Clinical Variable ◽  
Advisory Committees ◽  
Wbc Count

Background: Conventional risk factors for inferior outcomes in polycythemia vera (PV) include elevated hematocrit, white blood cell (WBC) count, age, and abnormal karyotype. Weight loss adversely impacts survival in cancer patients. JAK2 myeloproliferative neoplasms (MPN) upregulate tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8 and induce decreased leptin levels leading to weight loss. The impact of weight loss in PV patients receiving best supportive care (i.e. frontline hydroxyurea [HU] therapy, phlebotomy) on overall survival (OS) is largely unknown. In this study, we seek to investigate: (1) differential effect on survival for weight loss, and (2) variables with predictive value for weight loss among JAK2 inhibitor-naïve PV patients. Methods: After IRB approval, 46 patients at the Michael E. DeBakey VA Medical Center diagnosed with PV between 2000 and 2016 were selected for analysis. Our outcome of interest was OS among PV patients exhibiting weight loss versus patients who maintained, gained weight or had minor weight loss. To objectively estimate weight changes overtime, the difference between baseline BMI [BMI-B] at the time of diagnosis and BMI at last follow-up (BMI-L) was obtained for each patient. Survival analysis was performed for PV patients exhibiting more than 10% weight loss (&gt;10%) versus all other patients (less than 10% loss, stable and increased weight) (&lt;10%) over time. Kaplan-Meier (KM) method was used to determine OS. Cox regression model was performed to assess independent role of different variables including age, blood cell counts and ferritin level Statistical analysis was performed using SAS software. Results: Median BMI loss was 10% (0.03-36.72%); 33/46 (71.7%) and 13/46 (28.2%) patients developed &lt;10% and &gt;10% BMI loss, respectively. Baseline characteristics are summarized in Table 1. Median BMI at last follow up was 21 for PV patients exhibiting &gt;10% BMI loss and 27.7 for PV patients exhibiting &lt;10% BMI loss (p&lt;0.01). Median age was higher among patients exhibiting &gt;10% BMI loss (68 vs 56 y, respectively, p=0.006). A non-significant clinical trend for higher WBC was observed among patients losing &gt;10% BMI (10.9 vs 7.6 K/uL, p=0.08). Median Hemoglobin (Hb), hematocrit (Hct) and ferritin were intriguingly lower in the &gt;10% loss group at 16 vs 18.3 g/dL (p=0.01), 49.3 vs 54.2% (p=0.04) and 29.8 vs 50.6 ng/mL (p=0.09) respectively, while median RDW was higher at 18 vs 15.1% (p=0.01). OS was 9125 days vs 5364 days, in patients with &lt;10% and &gt;10% BMI loss, respectively (p=0.02, HR=0.20; CI 95% 0.04-0.84) (Figure 1). On multivariate analysis, age (hazard ratio [HR], 1.34; p&lt;0.02) and WBC count (HR, 1.57; p&lt;0.01), were predictive of OS. Conclusions: A subgroup of PV patients exhibit progressive weight loss. Over 10% BMI reduction is associated with decreased survival, suggesting that "early weight loss" is an independent clinical variable that predicts high risk PV. While a larger study is needed to validate this observation, this small study highlights the role of leukocytosis, advanced age and weight loss in PV. Confirmation of the observations reported here could unveil an important role for pharmacologic and/or dietary interventions to improve survival among high-risk PV patients. Disclosures Rivero: agios: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees.

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