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1.
JMIR Cancer ; 6(1): e16469, 2020 Apr 28.
Article in English | MEDLINE | ID: mdl-32343259

ABSTRACT

BACKGROUND: Achieving adequate levels of physical activity (PA) is especially important for cancer survivors to mitigate the side effects of cancer and its treatment as well as for other health benefits. Electronic health (eHealth)-based PA interventions may offer feasible alternatives to traditionally delivered programs and optimize physical recovery after a cancer diagnosis, but perspectives of cancer survivors on this new delivery medium have not been extensively explored. OBJECTIVE: The overall aim was to explore participants' perspectives of eHealth-enabled PA interventions to inform the design of a future intervention among cancer survivors. METHODS: The study took place in a designated cancer center in Dublin, Ireland. A preceding questionnaire-based study was conducted primarily to establish interest in participating in subsequent eHealth-based studies. A follow-on focus group study was conducted to explore the concept of eHealth-based PA interventions for cancer survivors. The data were analyzed using thematic analysis. RESULTS: The questionnaire-based study (N=102) indicated that participants had a high level of interest in participating in follow-on eHealth-based studies. The focus group study (n=23) indicated that, despite some trepidation, overall positivity was expressed by participants toward the concept of eHealth-based PA interventions. Four themes were generated: (1) Health impact, including PA as a barrier and as a motivating factor, (2) Education needs, which emphasized the need for integrated information about PA and to increase technical literacy, (3) Goal setting, which should be integrated within the technical specification as a motivating factor, and (4) Support needs, as well as the importance of personalized human interaction, in tandem with technology. CONCLUSIONS: Qualitative research at the pretrial phase adds value to the design of a complex intervention and is especially useful in an area such as eHealth. The findings highlighted an interest in participating in eHealth-focused research as well as barriers, training needs, and key design features that can be applied to optimize the design of future eHealth-based PA interventions in cancer.

2.
PeerJ ; 7: e6596, 2019.
Article in English | MEDLINE | ID: mdl-30863689

ABSTRACT

Hummingbirds consume sugars from nectar, sap and honeydew, and obtain protein, fat and minerals from arthropods. To date, the identity of arthropod taxa in hummingbird diets has been investigated by observation of foraging or examination of alimentary tract contents. Direct examination of nestling provisioning adds the extra complication of disturbance to the young and mother. Here, we show that arthropod food items provisioned to Rufous hummingbird (Selasphorus rufus) nestlings can be identified by a safe and non-invasive protocol using next-generation sequencing (NGS) of DNA from nestling fecal pellets collected post-fledging. We found that females on southern Vancouver Island (British Columbia, Canada) provisioned nestlings with a wide range of arthropod taxa. The samples examined contained three Classes, eight Orders, 48 Families, and 87 Genera, with from one to 15 Families being identified in a single pellet. Soft-bodied Dipterans were found most frequently and had the highest relative abundance; hard-bodied prey items were absent from almost all samples. Substantial differences in taxa were found within season and between years, indicating the importance of multi-year sampling when defining a prey spectrum.

3.
Physiotherapy ; 104(4): 359-366, 2018 12.
Article in English | MEDLINE | ID: mdl-30318126

ABSTRACT

BACKGROUND: Randomised controlled trials (RCTs) are described as the gold standard of investigative clinical research. Evidence based practice is critical to the physiotherapy profession, and it is therefore important to explore the research underpinning practice by examining published RCTs. OBJECTIVES: The main aims of this review were to profile the quantity and quality of RCTs published in the journal Physiotherapy over the past 50 years. DATA SOURCES: Physiotherapy journal, hand searched (1967 to 1987) and electronically (1988 to 2017). STUDY SELECTION OR ELIGIBILITY CRITERIA: Studies identified as RCTs. STUDY APPRAISAL AND SYNTHESIS METHODS: Quality assessed via PEDRO criteria. RESULTS: 120 RCTs were identified from January 1967 to January 2017. The frequency of RCTs published has increased steadily and the UK was the most common source of RCTs, but the prevalence of non-UK based trials is increasing. The quality of RCTs improved steadily over the decades, with a mean PEDro score of 6.9 in the most recent decade (2017 to 2008), indicative of 'high quality'. The mean number of trial participants was 60 and the most commonly evaluated area was musculoskeletal physiotherapy. LIMITATIONS: RCTs were not evaluated against CONSORT criteria. CONCLUSION AND IMPLICATIONS OF KEY FINDINGS: Frequency of publication of RCTs in the journal Physiotherapy has increased over this time, mirroring trends in the wider medical literature. This highlights the predominance of some areas of research such as musculoskeletal and exercise-based research while other prominent areas such as neurology appear to be less researched.


Subject(s)
Periodicals as Topic/statistics & numerical data , Physical Therapy Modalities/statistics & numerical data , Randomized Controlled Trials as Topic/statistics & numerical data , Bibliometrics , Humans , Retrospective Studies
4.
Support Care Cancer ; 26(10): 3323-3336, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29909476

ABSTRACT

PURPOSE: Achieving adequate levels of physical activity (PA) and avoiding sedentary behaviour are particularly important in cancer survivors. eHealth, which includes, but is not limited to, the delivery of health information through Internet and mobile technologies, is an emerging concept in healthcare which may present opportunities to improve PA in cancer survivors. The aim of this systematic review was to explore the effects of eHealth in the promotion of PA among cancer survivors. METHODS: Suitable articles were searched using PubMed, CINAHL, EMBASE, PsychInfo, Web of Science and SCOPUS databases using a combination of keywords and medical subject headings. Articles were included if they described an eHealth intervention designed to improve PA in cancer survivors. Two reviewers screened studies for inclusion. RESULTS: In total, 1065 articles were considered. Ten studies met eligibility criteria. A variety of platforms designed to increase PA were described in these studies: web application (app) (n = 5), web and mobile application (n = 2), mobile app (n = 1), website only (n = 1), e-mail based (n = 1). All studies measured PA using self-report outcome measures with the exception of one study which measured steps using a Fitbit. Meta-analysis was not performed because of variations in study design and interventions. All studies reported improvements in PA, with 8/10 studies reporting statistically significant changes. CONCLUSION: The use of eHealth to promote PA in cancer survivors is a relatively new concept, which is supported by the recent emergent evidence described in this review. eHealth shows promise as a means of promoting and increasing daily PA, but further high-quality, longer term studies are needed to establish the feasibility and effectiveness of eHealth platforms aimed at that goal.


Subject(s)
Cancer Survivors , Exercise , Health Promotion/methods , Telemedicine , Cancer Survivors/education , Cancer Survivors/psychology , Cancer Survivors/statistics & numerical data , Continuity of Patient Care/organization & administration , Continuity of Patient Care/statistics & numerical data , Health Promotion/organization & administration , Health Promotion/statistics & numerical data , Humans , Internet , Mobile Applications , Program Evaluation , Sedentary Behavior , Telemedicine/methods , Telemedicine/statistics & numerical data
5.
J Cancer Surviv ; 12(4): 601-618, 2018 08.
Article in English | MEDLINE | ID: mdl-29796931

ABSTRACT

PURPOSE: The management of oesophageal and gastric cancer can cause significant physical decline, impacting on completion rates and outcomes. This systematic review aimed to (i) determine the impact of chemotherapy, chemoradiotherapy and surgery on physical function; (ii) identify associations between physical function and post-operative outcomes; and (iii) examine the effects of rehabilitation on physical function. METHODS: We included randomised controlled trials (RCT), non-RCTs of interventions and cohort studies that measured physical function by objective means in patients with oesophageal or gastric cancer. EMBASE, PubMed, CINAHL, Cochrane Library, SCOPUS, PEDro and the WHO Trial Registry were searched up to June 2016. Risk of bias assessment was performed using a suite of validated tools. RESULTS: Twenty-five studies involving 1897 participants were included. A meta-analysis was not indicated due to the heterogeneity of the literature. Significant reductions in physical function occur in patients undergoing neoadjuvant treatment and in the first 3 months post-resection. Lower pre-operative exercise capacity is associated with an increased risk of post-operative pulmonary complications (PPCs). Evidence to support exercise prehabilitation and rehabilitation in these treatment pathways is currently lacking. CONCLUSIONS: Chemotherapy, chemoradiation and surgery lead to reduced physical function in patients with oesophageal and gastric cancer. High quality evidence is lacking to prove the benefit of interventions that improve physical function through the treatment pathway and in recovery, and well-designed studies are required. This review was limited due to the heterogeneity of the literature, high risk of bias in some articles and the lack of high quality research encompassing sufficient time points in the patient journey. IMPLICATIONS FOR CANCER SURVIVORS: Curative treatment for oesophago-gastric cancer can negatively impact on physical function. Rehabilitation programmes have considerable potential to enhance physical function across the oesophago-gastric cancer journey.


Subject(s)
Esophageal Neoplasms/therapy , Exercise/physiology , Palliative Care/methods , Physical Fitness/physiology , Stomach Neoplasms/therapy , Activities of Daily Living/psychology , Adult , Aged , Cancer Survivors/statistics & numerical data , Chemoradiotherapy , Esophageal Neoplasms/epidemiology , Esophageal Neoplasms/rehabilitation , Exercise Therapy/statistics & numerical data , Female , Humans , Male , Middle Aged , Observational Studies as Topic/statistics & numerical data , Palliative Care/statistics & numerical data , Quality of Life , Randomized Controlled Trials as Topic/statistics & numerical data , Remission Induction/methods , Stomach Neoplasms/epidemiology , Stomach Neoplasms/rehabilitation , Young Adult
6.
PLoS One ; 12(8): e0183132, 2017.
Article in English | MEDLINE | ID: mdl-28817596

ABSTRACT

Anthropogenic climate change is predicted to have profound effects on species distributions over the coming decades. In this paper, we used maximum entropy modelling (Maxent) to estimate the effects of projected changes in climate on extent of climatically-suitable habitat for two Nepenthes pitcher plant species in Borneo. The model results predicted an increase in area of climatically-suitable habitat for the lowland species Nepenthes rafflesiana by 2100; in contrast, the highland species Nepenthes tentaculata was predicted to undergo significant loss of climatically-suitable habitat over the same period. Based on the results of the models, we recommend that research be undertaken into practical mitigation strategies, as approximately two-thirds of Nepenthes are restricted to montane habitats. Highland species with narrow elevational ranges will be at particularly high risk, and investigation into possible mitigation strategies should be focused on them.


Subject(s)
Climate Change , Magnoliopsida/physiology , Tropical Climate , Ecosystem , Models, Biological
8.
J Physiother ; 63(1): 30-39, 2017 01.
Article in English | MEDLINE | ID: mdl-27989730

ABSTRACT

QUESTIONS: Does a 3-month behaviour change intervention targeting physical activity (PA) increase habitual physical activity in adults with ankylosing spondylitis (AS)? Does the intervention improve health-related physical fitness, AS-related features, and attitude to exercise? Are any gains maintained over a 3-month follow-up? DESIGN: Parallel-group, randomised, controlled trial with concealed allocation, assessor blinding and intention-to-treat analysis. PARTICIPANTS: Forty adults with a diagnosis of AS, on stable medication, and without PA-limiting comorbidities. INTERVENTION: Over a 3-month period, the experimental group engaged in individually-tailored, semi-structured consultations aiming to motivate and support individuals in participating in PA. The control group continued with usual care. OUTCOME MEASURES: The primary outcome was PA measured by accelerometry over 1 week. Secondary outcomes included clinical questionnaires and measures of health-related physical fitness. Measures were taken at baseline, post-intervention, and after a 3-month follow-up period. RESULTS: Baseline characteristics were similar across groups, except age and body composition. There were statistically significant, moderate-to-large time-by-group effects in health-enhancing PA (mixed-design ANOVA for overall effect F(2, 76)=14.826, p<0.001), spinal mobility (F(2, 76)=5.691, p<0.005) and quality of life (χ2(2)=8.400, p<0.015) favouring the intervention group; post-intervention improvements were sustained 3 months later. No significant effects were seen in other physical fitness outcomes or on clinical questionnaires. No adverse effects were reported during the study. CONCLUSION: Health-enhancing PA, spinal mobility and quality of life were significantly improved after the intervention, and improvements were maintained at 3-month follow-up. TRIAL REGISTRATION: NCT02374502. [O'Dwyer T, Monaghan A, Moran J, O'Shea F, Wilson F (2016) Behaviour change intervention increases physical activity, spinal mobility and quality of life in adults with ankylosing spondylitis: a randomised trial.Journal of PhysiotherapyXX: XX-XX].


Subject(s)
Exercise/psychology , Health Behavior , Physical Fitness/psychology , Quality of Life/psychology , Range of Motion, Articular , Spondylitis, Ankylosing/rehabilitation , Adult , Analysis of Variance , Female , Health Promotion/methods , Humans , Male , Middle Aged , Self Efficacy , Spondylitis, Ankylosing/psychology
9.
J Clin Anesth ; 35: 446-455, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27871573

ABSTRACT

STUDY OBJECTIVE: To assess the ability of field tests of exercise tolerance, such as the 6-minute walk test (6MWT) and incremental shuttle walk test (ISWT), to predict postoperative outcome following intra-abdominal surgery. DESIGN: A systematic review. SETTING: A hospital-affiliated university. MEASUREMENTS: The following databases were searched: AMED, CINAHL, EMBASE, PEDro, PubMed/MEDLINE, and The Cochrane Library. Six full-text articles were included. Data extraction included author, population demographics, surgery type, postoperative outcome measure, and field test results. The risk of bias was performed using the Quality in Prognosis Studies tool. RESULTS: Surgical procedures reviewed were colorectal (n=3), upper gastrointestinal (n=1), and intra-abdominal surgery (n=2). Field tests of exercise tolerance showed little ability to predict postoperative mortality; however, the overall rate of mortality was low. Patients achieving lower distances on the ISWT tended to have longer hospital stays and an increased risk of overall complications. The 6MWT does not appear able to predict postoperative cardiac or pulmonary complications; however, it may be suitable to predict general complications. CONCLUSIONS: Field tests may be able to predict postoperative outcome; however, further validation is needed. The ISWT appears to be the superior field test. The 6MWT and stair climb test require further validation to assess their predictive ability.


Subject(s)
Abdomen/surgery , Exercise Tolerance/physiology , Postoperative Complications/diagnosis , Preoperative Care/methods , Walk Test/statistics & numerical data , Humans , Postoperative Complications/physiopathology , Predictive Value of Tests
10.
Surgery ; 160(5): 1189-1201, 2016 11.
Article in English | MEDLINE | ID: mdl-27397681

ABSTRACT

BACKGROUND: Preoperative physical fitness is predictive of postoperative outcome. Patients with lesser aerobic capacity are at greater risk of postoperative complications, longer hospital stays, and mortality. Prehabilitation may improve physical fitness, but it is unknown whether enhanced fitness translates to an improvement in postoperative outcome. METHODS: This systematic review and meta-analysis aimed to assess the ability of prehabilitation to influence postoperative outcome after intra-abdominal operations. Randomized controlled trials with at least 1 group undergoing a preoperative exercise intervention/prehabilitation were included. The following databases were searched: AMED, CINAHL, EMBASE, PubMed/Medline, and The Cochrane Library. Data extracted from 9 full-articles included author(s), population demographics, type of operation, postoperative measures of outcome, and type of treatment of the prehabilitation and control groups. Methodologic quality was assessed using GRADEpro, and the Cochrane risk of bias tool was used to measure study bias. RESULTS: Prehabilitation consisting of inspiratory muscle training, aerobic exercise, and/or resistance training can decrease all types of postoperative complications after intra-abdominal operations (odds ratio: 0.59, 95% confidence interval: 0.38-0.91, P = .03). It is unclear from our meta-analysis whether prehabilitation can decrease postoperative length of stay, because the number of studies that examined length of stay was small (n = 4). No postoperative mortality was reported in any study, and conclusions could not be drawn on the ability of exercise to influence operative mortality. The methodologic quality of studies was, however, "very low." CONCLUSION: Prehabilitation appears to be beneficial in decreasing the incidence of postoperative complications; however, more high-quality studies are needed to validate its use in the preoperative setting.


Subject(s)
Digestive System Surgical Procedures/mortality , Exercise Therapy/methods , Physical Fitness/physiology , Postoperative Complications/prevention & control , Preoperative Care/methods , Abdomen/surgery , Cause of Death , Digestive System Surgical Procedures/methods , Exercise/physiology , Female , Hospital Mortality/trends , Humans , Length of Stay , Male , Randomized Controlled Trials as Topic , Risk Assessment , Treatment Outcome
11.
Gait Posture ; 42(1): 23-6, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25891530

ABSTRACT

Crutches are commonly prescribed to patients with lower limb dysfunction during rehabilitation to assist with mobility. The aim of this study was to determine the energy expenditure for non-weight bearing crutch walking on level ground and ascending stairs at a self selected speed in a healthy adult population. Thirty-one healthy male and female adults (mean±SD: age 21.6±1.2 years; height 170.8±10.8 cm; weight 70.8±11.4 kg) mobilised non-weight bearing with elbow crutches along a 30 m corridor and (with one crutch) up a flight of 13 stairs. Energy expenditure for each activity was measured by indirect calorimetry using the COSMED K4b(2) portable ergospirometry system. The established VO2 values were 16.4ml/kg/min for crutch walking on level ground and 17.85 ml/kg/min for stair climbing. Non-weight bearing crutch walking at a self selected speed on the level ground and up a flight of stairs resulted in a MET value of 4.57 and 5.06 respectively. The mean heart rate (HR) for crutch walking along the flat was 117.06±20.54 beats per minute (bpm), while the mean HR for ambulating upstairs with crutches was 113.91±19.32 bpm. The increased energy demands of non-weight bearing crutch walking should be considered by physical therapists when instructing patients on crutch use. Further investigation to determine the implications of these results in populations with chronic disease is warranted.


Subject(s)
Crutches , Energy Metabolism/physiology , Gait/physiology , Walking/physiology , Weight-Bearing/physiology , Calorimetry, Indirect , Female , Humans , Male , Reference Values , Young Adult
12.
Ann Bot ; 112(7): 1279-91, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23975653

ABSTRACT

BACKGROUND AND AIMS: Nepenthes (Nepenthaceae, approx. 120 species) are carnivorous pitcher plants with a centre of diversity comprising the Philippines, Borneo, Sumatra and Sulawesi. Nepenthes pitchers use three main mechanisms for capturing prey: epicuticular waxes inside the pitcher; a wettable peristome (a collar-shaped structure around the opening); and viscoelastic fluid. Previous studies have provided evidence suggesting that the first mechanism may be more suited to seasonal climates, whereas the latter two might be more suited to perhumid environments. In this study, this idea was tested using climate envelope modelling. METHODS: A total of 94 species, comprising 1978 populations, were grouped by prey capture mechanism (large peristome, small peristome, waxy, waxless, viscoelastic, non-viscoelastic, 'wet' syndrome and 'dry' syndrome). Nineteen bioclimatic variables were used to model habitat suitability at approx. 1 km resolution for each group, using Maxent, a presence-only species distribution modelling program. KEY RESULTS: Prey capture groups putatively associated with perhumid conditions (large peristome, waxless, viscoelastic and 'wet' syndrome) had more restricted areas of probable habitat suitability than those associated putatively with less humid conditions (small peristome, waxy, non-viscoelastic and'dry' syndrome). Overall, the viscoelastic group showed the most restricted area of modelled suitable habitat. CONCLUSIONS: The current study is the first to demonstrate that the prey capture mechanism in a carnivorous plant is constrained by climate. Nepenthes species employing peristome-based and viscoelastic fluid-based capture are largely restricted to perhumid regions; in contrast, the wax-based mechanism allows successful capture in both perhumid and more seasonal areas. Possible reasons for the maintenance of peristome-based and viscoelastic fluid-based capture mechanisms in Nepenthes are discussed in relation to the costs and benefits associated with a given prey capture strategy.


Subject(s)
Insecta/physiology , Paleontology , Sarraceniaceae/physiology , Tropical Climate , Animals , Ecosystem , Models, Biological
14.
Plant Signal Behav ; 7(10): 1267-70, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-22902686

ABSTRACT

Three species of Nepenthes pitcher plants (Nepenthes rajah, Nepenthes lowii and Nepenthes macrophylla) specialize in harvesting nutrients from tree shrew excreta in their pitchers. In all three species, nectaries on the underside of the pitcher lid are the focus of the tree shrews' attention. Tree shrews are dichromats, with visual sensitivity in the blue and green wavebands. All three Nepenthes species were shown to produce visual signals, in which the underside of the pitcher lid (the area of highest nectar production) stood out in high contrast to the adjacent area on the pitcher (i.e., was brighter), in the blue and green wavebands visible to the tree shrews. N. rajah showed the tightest degree of "tuning," notably in the green waveband. Conversely, pitchers of Nepenthes burbidgeae, a typical insectivorous species sympatric with N. rajah, did not produce a color pattern tuned to tree shrew sensitivity maxima.


Subject(s)
Contrast Sensitivity/physiology , Sarraceniaceae/physiology , Tupaiidae/physiology , Animals , Area Under Curve , Borneo , Color , Species Specificity
15.
Plant Signal Behav ; 7(8): 957-60, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22836498

ABSTRACT

Nepenthes pitcher plants deploy tube-shaped pitchers to catch invertebrate prey; those of Nepenthes aristolochioides possess an unusual translucent dome. The hypothesis was tested that N. aristolochioides pitchers operate as light traps, by quantifying prey capture under three shade treatments. Flies are red-blind, with visual sensitivity maxima in the UV, blue, and green wavebands. Red celluloid filters were used to reduce the transmission of these wavebands into the interior of the pitchers. Those that were shaded at the rear showed a 3-fold reduction in Drosophila caught, relative to either unshaded control pitchers, or pitchers that were shaded at the front. Thus, light transmitted through the translucent dome is a fundamental component of N. aristolochioides' trapping mechanism.


Subject(s)
Drosophila melanogaster , Light , Sarraceniaceae/physiology , Sarraceniaceae/radiation effects , Tropical Climate , Animals , Drosophila melanogaster/physiology , Pigmentation/radiation effects , Sarraceniaceae/anatomy & histology , Sarraceniaceae/ultrastructure
16.
PLoS One ; 7(5): e36179, 2012.
Article in English | MEDLINE | ID: mdl-22590524

ABSTRACT

Scarcity of essential nutrients has led plants to evolve alternative nutritional strategies, such as myrmecotrophy (ant-waste-derived nutrition) and carnivory (invertebrate predation). The carnivorous plant Nepenthes bicalcarata grows in the Bornean peatswamp forests and is believed to have a mutualistic relationship with its symbiotic ant Camponotus schmitzi. However, the benefits provided by the ant have not been quantified. We tested the hypothesis of a nutritional mutualism, using foliar isotopic and reflectance analyses and by comparing fitness-related traits between ant-inhabited and uninhabited plants. Plants inhabited by C. schmitzi produced more leaves of greater area and nitrogen content than unoccupied plants. The ants were estimated to provide a 200% increase in foliar nitrogen to adult plants. Inhabited plants also produced more and larger pitchers containing higher prey biomass. C. schmitzi-occupied pitchers differed qualitatively in containing C. schmitzi wastes and captured large ants and flying insects. Pitcher abortion rates were lower in inhabited plants partly because of herbivore deterrence as herbivory-aborted buds decreased with ant occupation rate. Lower abortion was also attributed to ant nutritional service. The ants had higher δ(15)N values than any tested prey, and foliar δ(15)N increased with ant occupation rate, confirming their predatory behaviour and demonstrating their direct contribution to the plant-recycled N. We estimated that N. bicalcarata derives on average 42% of its foliar N from C. schmitzi wastes, (76% in highly-occupied plants). According to the Structure Independent Pigment Index, plants without C. schmitzi were nutrient stressed compared to both occupied plants, and pitcher-lacking plants. This attests to the physiological cost of pitcher production and poor nutrient assimilation in the absence of the symbiont. Hence C. schmitzi contributes crucially to the nutrition of N. bicalcarata, via protection of assimilatory organs, enhancement of prey capture, and myrmecotrophy. This combination of carnivory and myrmecotrophy represents an outstanding strategy of nutrient sequestration.


Subject(s)
Ants/physiology , Magnoliopsida/physiology , Symbiosis/physiology , Animals , Borneo , Feeding Behavior/psychology
17.
Plant Signal Behav ; 5(6): 644-8, 2010 Jun.
Article in English | MEDLINE | ID: mdl-21135573

ABSTRACT

Nepenthes is the largest genus of pitcher plants, with its centre of diversity in SE Asia. The plants grow in substrates that are deficient in N and offset this deficiency by trapping animal prey, primarily arthropods. Recent research has provided new insights into the function of the pitchers, particularly with regard to prey tapping and retention. Species examined to date use combinations of wettable peristomes, wax layers and viscoelastic fluid to trap and retain prey. In many respects, this has redefined our understanding of the functioning of Nepenthes pitchers. In addition, recent research has shown that several Nepenthes species target specific groups of prey animals, or are even evolving away from a strictly carnivorous mode of operation. Future research into nutrient sequestration strategies and mechanisms of prey attraction would no doubt further enhance our knowledge of the ecology of this remarkable genus.


Subject(s)
Magnoliopsida/physiology , Animals , Insecta/metabolism
18.
Plant Signal Behav ; 5(10): 1187-9, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20861680

ABSTRACT

Three species of Nepenthes pitcher plants from Borneo engage in a mutualistic interaction with mountain tree shrews, the basis of which is the exchange of nutritional resources. The plants produce modified "toilet pitchers" that produce copious amounts of exudates, the latter serving as a food source for tree shrews. The exudates are only accessible to the tree shrews when they position their hindquarters over the pitcher orifice. Tree shrews mark valuable resources with faeces and regularly defecate into the pitchers when they visit them to feed. Faeces represent a valuable source of nitrogen for these Nepenthes species, but there are many facets of the mutualism that are yet to be investigated. These include, but are not limited to, seasonal variation in exudate production rates by the plants, behavioral ecology of visiting tree shrews, and the mechanism by which the plants signal to tree shrews that their pitchers represent a food source. Further research into this extraordinary animal-plant interaction is required to gain a better understanding of the benefits to the participating species.


Subject(s)
Research , Sarraceniaceae/physiology , Symbiosis/physiology , Tupaiidae/physiology , Animals , Ecosystem
19.
J Exp Bot ; 61(5): 1365-74, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20150519

ABSTRACT

Nepenthes pitcher plant species differ in their prey capture strategies, prey capture rates, and pitcher longevity. In this study, it is investigated whether or not interspecific differences in nutrient sequestration strategy are reflected in the physiology and microstructure of the pitchers themselves. Using a non-invasive technique (MIFE), ion fluxes in pitchers of Nepenthes ampullaria Jack, Nepenthes bicalcarata Hook.f., and Nepenthes rafflesiana Jack were measured. Scanning electron microscopy was also used to characterize the distribution of glandular and other structures on the inner pitcher walls. The results demonstrate that nutrient sequestration strategy is indeed mirrored in pitcher physiology and microstructure. Species producing long-lived pitchers with low prey capture rates (N. ampullaria, N. bicalcarata) showed lower rates of NH(4)(+) uptake than N. rafflesiana, a species producing short-lived pitchers with high capture rates. Crucially, species dependent upon aquatic commensals (N. ampullaria, N. bicalcarata) actively manipulated H(+) fluxes to maintain less acid pitcher fluid than found in 'typical' species; in addition, these species lacked the lunate cells and epicuticular waxes characteristic of 'typical' insectivorous congeners. An unexpected finding was that ion fluxes occurred in the wax-covered, non-glandular zones in N. rafflesiana. The only candidates for active transport of aqueous ions in these zones appear to be the epidermal cells lying beneath the lunate cells, as these are the only sites not visibly coated with epicuticular waxes.


Subject(s)
Biological Transport/physiology , Ions/metabolism , Magnoliopsida/metabolism , Magnoliopsida/physiology , Nitrogen/metabolism , Magnoliopsida/ultrastructure , Microscopy, Electron, Scanning , Protons , Quaternary Ammonium Compounds
20.
New Phytol ; 186(2): 461-70, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20100203

ABSTRACT

*Three Bornean pitcher plant species, Nepenthes lowii, N. rajah and N. macrophylla, produce modified pitchers that 'capture' tree shrew faeces for nutritional benefit. Tree shrews (Tupaia montana) feed on exudates produced by glands on the inner surfaces of the pitcher lids and defecate into the pitchers. *Here, we tested the hypothesis that pitcher geometry in these species is related to tree shrew body size by comparing the pitcher characteristics with those of five other 'typical' (arthropod-trapping) Nepenthes species. *We found that only pitchers with large orifices and lids that are concave, elongated and oriented approximately at right angles to the orifice capture faeces. The distance from the tree shrews' food source (that is, the lid nectar glands) to the front of the pitcher orifice precisely matches the head plus body length of T. montana in the faeces-trapping species, and is a function of orifice size and the angle of lid reflexion. *Substantial changes to nutrient acquisition strategies in carnivorous plants may occur through simple modifications to trap geometry. This extraordinary plant-animal interaction adds to a growing body of evidence that Nepenthes represents a candidate model for adaptive radiation with regard to nitrogen sequestration strategies.


Subject(s)
Body Size , Sarraceniaceae/anatomy & histology , Tupaiidae/anatomy & histology , Animals , Biomass , Borneo , Feces , Montana , Principal Component Analysis , Regression Analysis , Species Specificity
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