Predatory Behavior and Prey Selectivity of the Pelagic Water Mite Piona constricta

1982 ◽  
Vol 39 (12) ◽  
pp. 1569-1579 ◽  
Author(s):  
Howard P. Riessen

Predation by the pelagic water mite Piona constricta on the various components of the zooplankton community of Heney Lake, Quebec, Canada, was investigated through both direct observation and several series of feeding experiments. On encountering a prey item, the mite seized the organism with its four pairs of legs and pair of palps and tore a hole in the body wall with its chelicerae. The soft body tissues of the prey were predigested and the liquid nutriment was then drawn into the mouth. Pionid adults ate an average of 10–15 prey∙mite−1∙d−1 and selected prey items as follows: Bosmina > Daphnia, Ceriodaphnia > Chydorus >> Diaphanosoma, Diaptomus > Mesocyclops. The nymphs ate only 2–3 prey∙mite−1∙d−1 with Bosmina and Chydorus as the preferred items. The other cladocerans and the copepods were only rarely eaten. The pattern of prey selection for the adults and nymphs appeared to depend primarily on the escape response of the prey (their ability to detect an approaching mite and flee the area before being grabbed). Prey size and carapace thickness were of secondary importance.Key words: water mites, Piona constricta; zooplankton, predator–prey interactions

1985 ◽  
Vol 42 (11) ◽  
pp. 1720-1732 ◽  
Author(s):  
Scott D. Cooper ◽  
Daniel W. Smith ◽  
James R. Bence

We observed several freshwater predators, including the odonate larvae Pachydiplax longipennis and Anax junius, the hemipterans Notonecta unifasciata and Buenoa scimitra, the dytiscid larva Acilius semisulcatus, and juvenile Gambusia affinis, feeding on a variety of microcrustacean prey and determined the frequency of the component parts of predator–prey interactions (encounter, attack, capture, ingestion). Encounter rates were the most important determinant of predator selectivity when predators were presented with a variety of microcrustacean prey. When only copepod species were used as prey, however, both encounter rates and capture success were important in determining predator diets. We used our data to test hypotheses concerning relationships between predator foraging mode and patterns of prey selection: mobile predators exhibited stronger selection for sedentary prey than did sit-and-wait predators; our own and literature data also indicated that macroinvertebrate sit-and-wait predators are better able to capture, and have higher selectivity for evasive prey than do mobile predators. A predator's attack acceleration, however, may be a better predictor of its selectivity for evasive versus nonevasive prey than its mean swimming speed.


2019 ◽  
Vol 11 (4) ◽  
pp. 277-284
Author(s):  
Vitrianingsih Vitrianingsih ◽  
Sitti Khadijah

Studi memperkirakan emesis gravidarum terjadi pada 50-90% kehamilan. Mual muntah pada kehamilan memberikan dampak yang signifikan bagi tubuh dimana ibu menjadi lemah, pucat dan cairan tubuh berkurang sehingga darah menjadi kental (hemokonsentrasi). Keadaan ini dapat memperlambat peredaran darah dan berakibat pada kurangnya suplay oksigen serta makanan ke jaringan sehingga dapat membahayakan kesehatan ibu dan janin. Salah satu terapi yang aman dan dapat dilakukan untuk mengurangi keluahan mual muntah pada ibu hamil adalah pemberian aromaterapi lemon. Penelitian bertujuan untuk mengetahui efektifitas aroma terapi lemon untuk menangani emesis gravidarum. Penelitian ini menggunakan rancangan Quasi experiment  dengan  one group pre-post test design. Populasi penelitian adalah ibu hamil yang mengalami emesis gravidarum di Kecamatan Berbah, Sleman. Jumlah sampel 20 ibu hamil trimester pertama yang diambil dengan teknik purposive sampling. Pengukuran mual muntah dilakukan debelum dan setelah  pemberian aromaterapi lemon menggunakan Indeks Rhodes. Analisa data menggunakan uji Paired t-test. Hasil penelitian didapatkan rata-rata skor mual muntah sebelum pemberian aromaterapi lemon berdasarkan Indeks Rhodes pada Ibu Hamil dengan emesis gravidarum yaitu 22,1 dan terjadi penurunan skor setelah pemberian aromaterapi lemon menjadi 19,8. Ada pengaruh pemberian aromaterapi lemon dengan pengurangan mual muntah pada ibu hamil (p-value = 0.017). Berdasarkan hasil penelitian dapat disimpulkan pemberian aromaterapi lemon efektif untuk mengurangi emesis gravidarum pada ibu hamil trimester pertama.  Kata kunci: aromaterapi lemon, emesis gravidarum THE EFFECTIVENESS OF LEMON AROMATHERAPY FOR HANDLING EMESIS GRAVIDARUM   ABSTRACT Studies estimate that nausea and vomiting (emesis gravidarum) occur in 50 – 90% of pregnancies. Nausea and vomiting of pregnancy have a significant impact on the body in which it makes a mother becomes weak, pale, and decreasing body fluid so that the blood becomes thick (hemoconcentration). This situation can slow down blood circulation and inflict the lack of oxygen and food supplies to the body tissues so that it can endanger the health of the mother and fetus. One of the therapies that is safe and can be conducted to reduce nausea and vomiting of pregnancy is by giving the lemon aromatherapy treatment. The research aims to determine the effectiveness of the aroma of lemon therapy to deal with emesis gravidarum. This study applied quasi-experimental research with one group pretest-posttest design. The population of this study was pregnant women who experienced emesis gravidarum. Furthermore, samples were 20 mothers from Berbah, Sleman taken by using a purposive sampling technique. Nausea and vomiting were assessed between before and after giving lemon aromatherapy using the Rhodes Index. The data were analyzed using the paired t-test. The mean score of nausea and vomiting before giving lemon aromatherapy on mother with emesis gravidarum based on the Rhodes Index was 22.1. However, it decreased after given lemon aromatherapy treatment to 19.8. Therefore, there was an effect on giving lemon aromatherapy treatment toward the decrease of nausea and vomiting for pregnant women (p-value = 0.017). Lemon aromatherapy is effective to reduce emesis gravidarum.  Keywords: lemon aromatherapy, emesis gravidarum


Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.


2019 ◽  
Vol 20 (7) ◽  
pp. 661-665
Author(s):  
Cunxi Nie ◽  
Fei Xie ◽  
Ning Ma ◽  
Yueyu Bai ◽  
Wenju Zhang ◽  
...  

As a major component of biologically active compounds in the body, proteins contribute to the synthesis of body tissues for the renewal and growth of the body. The high level of dietary protein and the imbalance of amino acid (AA) composition in mammals result in metabolic disorders, inefficient utilization of protein resources and increased nitrogen excretion. Fortunately, nutritional interventions can be an effective way of attenuating the nitrogen excretion and increasing protein utilization, which include, but are not limited to, formulating the AA balance and protein-restricted diet supplementing with essential AAs, and adding probiotics in the diet. This review highlights recent advances in the turnover of dietary proteins and mammal’s metabolism for health, in order to improve protein bioavailability through nutritional approach.


1974 ◽  
Vol 82 (1) ◽  
pp. 87-95 ◽  
Author(s):  
E. F. Annison ◽  
R. Bickerstaffe ◽  
J. L. Linzell

SUMMARYThe effects of changing to a high starch: low roughage diet have been studied in two Friesian and two Jersey cows, surgically prepared for the simultaneous study of udder metabolism (arteriovenous difference x udder blood flow) and whole body turnover of milk precursors (isotope dilution).In the Friesian cows milk fat concentration was lower on the high starch diet but in the Jerseys fell only slightly in one animal. In both Friesians and in the one Jersey these changes were accompanied by an increase in total rumen VFA concentration. Rumen acetate concentration did not change but propionate doubled. Thus this confirms that the usually reported fall in ‘acetate:propionate ratio’ is due to a rise in propionate production rather than due to a fall in acetate production.There were significant falls in the blood concentrations of acetate and β-hydroxy-butyrate. The rate of extraction by the udder of acetate and β-hydroxybutyrate did not change but triglyceride extraction fell. Therefore since udder blood flow did not alter the uptake of all three fat precursors fell.The entry rate of glucose into the circulation and its contribution to total body CO2 increased. The entry rate and contribution to CO2 of acetate decreased but this was probably mainly due to a fall in endogenous acetate production by the body tissues. Plasma FFA concentration showed little change but the entry rate of palmitate fell on the high starch diet. There was also an increased proportion of unsaturated and trans fatty acids in the plasma and milk triglycerides.


2017 ◽  
Vol 44 (1) ◽  
pp. 28 ◽  
Author(s):  
N. T. Maruping-Mzileni ◽  
P. J. Funston ◽  
S. M. Ferreira

Aims Indicators of pending state-shifts carry value for policy makers. Predator–prey relations reflect key ecological processes that shape ecosystems. Variance in predator–prey relations may serve as a key indicator of future state-shifts. Methods Lion (Panthera leo) diet in the Kruger National Park was evaluated as such an indicator. Over the three-decade time span reviewed, variance in diet in relation to rainfall, prey abundance, management strategies and disease emergence were reviewed. Key results Rainfall patterns, both seasonal and cyclical, were identified as key drivers of predator–prey selection. However, the intensity of management in the form of artificial waterpoints overrode and confounded natural process. The results suggest that savanna systems are stable and punctuated by climatic events in the form of extreme above-average rainfall that temporarily destabilises the system. However, droughts are a cyclical part of the savanna system. Conclusion Lion prey selection did fluctuate with changing environmental conditions. Abrupt state shifts did occur; however, the ecosystem returned to a stable state. Implications State shifts in ecosystems pose key challenges to conservation managers. State shifts appear to be primarily associated with management interventions and environmental factors.


2021 ◽  
Vol 1040 ◽  
pp. 61-67
Author(s):  
Anna B. Vlasenko ◽  
Vadim V. Bakhmetyev ◽  
Sergey V. Mjakin

Photodynamic therapy (PDT) is a promising modern method for treatment of oncological, bacterial, fungal and viral diseases. However, its application is limited to diseases with superficial localization since the body tissues are not transparent for visible light. To address this problem and extend PDT application to abdominal diseases, an enhanced method of X-ray photodynamic therapy (XRPDT) is suggested, involving X-ray radiation easily penetrating the body tissues. The implementation of this approach requires the development of a pharmacological drug including a photosensitizer stimulated by visible light to yield active oxygen and a nanosized phosphor converting X-ray radiation into visible light with the wavelength required for the photosensitizer activation. This study is aimed at obtaining X-ray stimulated phosphors with nanosized particles suitable for XRPDT application. For this purpose, Y2O3:Eu phosphors were synthesized via hydrothermal processing of the corresponding mixed acetate followed by annealing. To prevent from the undesirable agglomeration of the particles in the course of hydrothermal synthesis and subsequent annealing, different techniques were used, including rapid thermal annealing (RTA), microwave annealing and addition of finely dispersed pyrogenic silica (aerosil) to the phosphor. The microwave annealing was carried out using a special installation including a resonance chamber for maintaining a standing wave of microwave radiation. The performed research allowed the determination of hydrothermal processing optimal duration affording the synthesis of phosphors with the highest luminescence brightness. The application of microwave annealing is found to provide phosphors with a more perfect crystal structure compared with RTA. The developed method of Y2O3:Eu phosphor synthesis involving pyrogenic silica addition to the autoclave allowed the preparation of samples with the amorphous structure and significantly reduced the particle size without a considerable decrease in the luminescence brightness. The particle size of the phosphor synthesized with aerosil addition is less than 100 nm that allows its implementation in pharmacological drugs for XRPDT.


1998 ◽  
Vol 201 (6) ◽  
pp. 837-850 ◽  
Author(s):  
K V Kardong ◽  
V L Bels

The predatory behavior of rattlesnakes includes many distinctive preparatory phases leading to an extremely rapid strike, during which venom is injected. The rodent prey is then rapidly released, removing the snake's head from retaliation by the prey. The quick action of the venom makes possible the recovery of the dispatched prey during the ensuing poststrike period. The strike is usually completed in less than 0.5 s, placing a premium on an accurate strike that produces no significant errors in fang placement that could result in poor envenomation and subsequent loss of the prey. To clarify the basis for effective strike performance, we examined the basic kinematics of the rapid strike using high-speed film analysis. We scored numerous strike variables. Four major results were obtained. (1) Neurosensory control of the strike is based primarily upon sensory inputs via the eyes and facial pits to launch the strike, and upon tactile stimuli after contact. Correction for errors in targeting occurs not by a change in strike trajectory, but by fang repositioning after the jaws have made contact with the prey. (2) The rattlesnake strike is based upon great versatility and variation in recruitment of body segments and body postures. (3) Forces generated during acceleration of the head are transferred to posterior body sections to decelerate the head before contact with the prey, thereby reducing impact forces upon the snake's jaws. (4) Body acceleration is based on two patterns of body displacement, one in which acute sections of the body open like a gate, the other in which body segments flow around postural curves similar to movements seen during locomotion. There is one major implication of these results: recruitment of body segments, launch postures and kinematic features of the strike may be quite varied from strike to strike, but the overall predatory success of each strike by a rattlesnake is very consistent. &lt;P&gt;


2021 ◽  
Vol 14 (2) ◽  
pp. e240214
Author(s):  
Lenny Thinagaran Vasanthan ◽  
Manigandan Chockalingam

Identification of the primary source of pain determines the success of musculoskeletal pain management. A detailed history and physical examination are the current gold standards for identifying musculoskeletal pain source in day-to-day clinical practice. This process, at times, may potentially result in inadequate/inappropriate identification of the pain source. In this case report, we present the usefulness of a simple and inexpensive vacuum cup. We found that this accurately identified the primary pain source, distant from and unrelated to the site of pain presentation in a 30-year-old man with back pain. Routine use of this simple technique in conjunction with the regular musculoskeletal examination may better identify primary restrictions in the body tissues. Based on our experience, we propose that this approach has the potential to offer better outcomes in the treatment of musculoskeletal pain in the future.


2017 ◽  
Vol 46 (3) ◽  
pp. 626-632 ◽  
Author(s):  
Jamie L. Rafter ◽  
Justin F. Vendettuoli ◽  
Liahna Gonda-King ◽  
Daniel Niesen ◽  
Navindra P. Seeram ◽  
...  

Abstract Prey have evolved a number of defenses against predation, and predators have developed means of countering these protective measures. Although caterpillars of the monarch butterfly,Danaus plexippus L., are defended by cardenolides sequestered from their host plants, the Chinese mantidTenodera sinensis Saussure guts the caterpillar before consuming the rest of the body. We hypothesized that this gutting behavior might be driven by the heterogeneous quality of prey tissue with respect to toxicity and/or nutrients. We conducted behavioral trials in which mantids were offered cardenolide-containing and cardenolide-freeD. plexippus caterpillars and butterflies. In addition, we fed mantids starved and unstarvedD. plexippus caterpillars from each cardenolide treatment and nontoxicOstrinia nubilalis Hübner caterpillars. These trials were coupled with elemental analysis of the gut and body tissues of bothD. plexippus caterpillars and corn borers. Cardenolides did not affect mantid behavior: mantids gutted both cardenolide-containing and cardenolide-free caterpillars. In contrast, mantids consumed bothO. nubilalis and starvedD. plexippus caterpillars entirely.Danaus plexippus body tissue has a lower C:N ratio than their gut contents, whileO. nubilalis have similar ratios; gutting may reflect the mantid’s ability to regulate nutrient uptake. Our results suggest that post-capture prey processing by mantids is likely driven by a sophisticated assessment of resource quality.


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