Archetype models upscale understanding of natural pest control response to land-use change

Control of crop pests by shifting host plant availability and natural enemy activity at landscape scales has great potential to enhance the sustainability of agriculture. However, mainstreaming natural pest control requires improved understanding of how its benefits can be realized across a variety of agroecological contexts. Empirical studies suggest significant but highly variable responses of natural pest control to land-use change. Current ecological models are either too specific to provide insight across agroecosystems or too generic to guide management with actionable predictions. We suggest obtaining the full benefit of available empirical, theoretical, and methodological knowledge by combining trait-mediated understanding from correlative studies with the explicit representation of causal relationships achieved by mechanistic modeling. To link these frameworks, we adapt the concept of archetypes, or context-specific generalizations, from sustainability science. Similar responses of natural pest control to land-use gradients across cases that share key attributes, such as functional traits of focal organisms, indicate general processes that drive system behavior in a context-sensitive manner. Based on such observations of natural pest control, a systematic definition of archetypes can provide the basis for mechanistic models of intermediate generality that cover all major agroecosystems worldwide. Example applications demonstrate the potential for upscaling understanding and improving predictions of natural pest control, based on knowledge transfer and scientific synthesis. A broader application of this mechanistic archetype approach promises to enhance ecology's contribution to natural resource management across diverse regions and social-ecological contexts.

Landscape Context Influences the Bee Conservation Value of Wildflower Plantings

Pollination provided by bees is a critical ecosystem service for agricultural production. However, bee populations are at risk from stressors such as habitat loss, pesticides, and disease. On-farm wildflower plantings is one mitigation strategy to provide habitat and resources for bees. In many instances, government programs can subsidize the installation of these plantings for private landowners. Semi-natural habitat (SNH) in the landscape is also important for bee conservation and may alter the effectiveness of wildflower plantings. In this study, we tested the effectiveness of wildflower plantings and interactions with SNH in the landscape for promoting bee abundance and richness. Bee surveys were conducted over 2 yr at 22 sites in eastern Virginia and Maryland. Wildflower plantings, averaging 0.22 ha in size, were installed and maintained by cooperators at 10 of the sites. In total, 5,122 bees were identified from 85 species. Wildflower plantings did not alter bee communities independently, but bee abundance was greater on farms with plantings and 20-30% SNH in the landscape. Bee abundance and richness had nonlinear responses to increasing SNH in the landscape. The positive effects for richness and abundance peaked when SNH was approximately 40% of the landscape. Similar to predictions of the intermediate-landscape complexity hypothesis, increases in bee abundance at wildflower sites were only detected in simplified landscapes. Results indicate that small wildflower plantings in the Mid-Atlantic U.S. only provided conservation benefits to bee communities under specific circumstances on the scale studied, and that conserving SNH across the landscape may be a more important strategy.

Species traits elucidate crop pest response to landscape composition: a global analysis

Recent synthesis studies have shown inconsistent responses of crop pests to landscape composition, imposing a fundamental limit to our capacity to design sustainable crop protection strategies to reduce yield losses caused by insect pests. Using a global dataset composed of 5242 observations encompassing 48 agricultural pest species and 26 crop species, we tested the role of pest traits (exotic status, host breadth and habitat breadth) and environmental context (crop type, range in landscape gradient and climate) in modifying the pest response to increasing semi-natural habitats in the surrounding landscape. For natives, increasing semi-natural habitats decreased the abundance of pests that exploit only crop habitats or that are highly polyphagous. On the contrary, populations of exotic pests increased with an increasing cover of semi-natural habitats. These effects might be related to changes in host plants and other resources across the landscapes and/or to modified top-down control by natural enemies. The range of the landscape gradient explored and climate did not affect pests, while crop type modified the response of pests to landscape composition. Although species traits and environmental context helped in explaining some of the variability in pest response to landscape composition, the observed large interspecific differences suggest that a portfolio of strategies must be considered and implemented for the effective control of rapidly changing communities of crop pests in agroecosystems.

A global synthesis reveals biodiversity-mediated benefits for crop production

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.

Low-intensity transcranial magnetic stimulation promotes the survival and maturation of newborn oligodendrocytes in the adult mouse brain

Neuronal activity is a potent extrinsic regulator of oligodendrocyte generation and central nervous system myelination. Clinically, repetitive transcranial magnetic stimulation (rTMS) is delivered to noninvasively modulate neuronal activity; however, the ability of rTMS to facilitate adaptive myelination has not been explored. By performing cre‐lox lineage tracing, to follow the fate of oligodendrocyte progenitor cells in the adult mouse brain, we determined that low intensity rTMS (LI‐rTMS), administered as an intermittent theta burst stimulation, but not as a continuous theta burst or 10 Hz stimulation, increased the number of newborn oligodendrocytes in the adult mouse cortex. LI‐rTMS did not alter oligodendrogenesis per se, but instead increased cell survival and enhanced myelination. These data suggest that LI‐rTMS can be used to noninvasively promote myelin addition to the brain, which has potential implications for the treatment of demyelinating diseases such as multiple sclerosis.

A multi-scale, landscape approach to predicting insect populations in agroecosystems

Landscape composition affects ecosystems services, including agricultural pest management. However, relationships between land use and agricultural insects are not well understood, and many complexities remain to be explored. Here we examine whether nonagricultural landscapes can directly suppress agricultural pests, how multiple spatial scales of land use concurrently affect insect populations, and the relationships between regional land use and insect populations. We tracked densities of three specialist corn (Zea mays) pests (Ostrinia nubilalis, European corn borer; Diabrotica virgifera, western corn rootworm; Diabrotica barberi, northern corn rootworm), and two generalist predator lady beetles (Coleomegilla maculata and Propylea quatuordecimpunctata) in field corn and determined their relationships to agricultural land use at three spatial scales (field perimeter, 1-km, and 20-km radius areas). Pest densities were either higher (D. virgifera and D. barberi) or unchanged (O. nubilalis) in landscapes with more corn, while natural enemy densities were either lower (C. maculata) or unchanged (P. quatuordecimpunctata). Results for D. virgifera and D. barberi indicate that decreasing the area of preferred crop in the landscape can directly suppress specialist insect pests. Multiple scales of land use affected populations of D. virgifera and C. maculata, and D. virgifera populations showed strong relationships with regional, 20-km-scale land use. These results suggest that farm planning and government policies aimed at diversifying local and regional agricultural landscapes show promise for increasing biological control and directly suppressing agricultural pests.

A meta-analysis of crop pest and natural enemy response to landscape complexity

Many studies in recent years have investigated the relationship between landscape complexity and pests, natural enemies and/or pest control. However, no quantitative synthesis of this literature beyond simple vote-count methods yet exists. We conducted a meta-analysis of 46 landscape-level studies, and found that natural enemies have a strong positive response to landscape complexity. Generalist enemies show consistent positive responses to landscape complexity across all scales measured, while specialist enemies respond more strongly to landscape complexity at smaller scales. Generalist enemy response to natural habitat also tends to occur at larger spatial scales than for specialist enemies, suggesting that land management strategies to enhance natural pest control should differ depending on whether the dominant enemies are generalists or specialists. The positive response of natural enemies does not necessarily translate into pest control, since pest abundances show no significant response to landscape complexity. Very few landscape-scale studies have estimated enemy impact on pest populations, however, limiting our understanding of the effects of landscape on pest control. We suggest focusing future research efforts on measuring population dynamics rather than static counts to better characterise the relationship between landscape complexity and pest control services from natural enemies.

Managing resistance to Bt crops in a genetically variable insect herbivore, Ostrinia nubilalis

To slow the resistance evolution of the European corn borer (ECB) to Cry proteins expressed in transgenic Bacillus thuringensis (Bt) corn, the United States Environmental Protection Agency (EPA) has adopted an insect resistance management (IRM) plan that relies on a "high dose/refuge" strategy. However, this IRM plan does not consider possible ecological differences between the two ECB pheromone races (E and Z). Using carbon isotope analysis, we found that unstructured (non-corn) refuges contribute more to E race (18%) than to Z race (4%) populations of ECB in upstate New York (USA). Furthermore, feeding on non-corn hosts is associated with decreased body mass and reduced fecundity. We also show that the geographic range of E-race ECB is restricted within the range of the Z race and that E-race ECB are increasingly dominant in regions with increasing non-corn habitat. While the proportion of E-race ECB developing in unstructured refuges is higher than previously assumed, low rates of unstructured refuge use by the Z race, evidence for reduced fecundity when reared on non-corn hosts, and complete sympatry within the E race range all argue against a relaxation of current IRM refuge standards in corn based on alternative-host use. We also discuss implications of this research for integrated pest management in vegetables and IRM in Bt cotton.

Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems

Ground beetles (Coleoptera: Carabidae) are important in agro-ecosystems as generalist predators of invertebrate pests and weed seeds and as prey for larger animals. However, it is not well understood how cropping systems affect ground beetles. Over a 2-yr period, carabids were monitored two times per month using pitfall traps in a conventional chemical input, 2-yr, corn/soybean rotation system and a low input, 4-yr, corn/soybean/triticale-alfalfa/alfalfa rotation system. Carabid assemblages were largely dominated by a few species across all cropping treatments with Poecilus chalcites Say comprising >70% of pitfall catches in both years of study. Overall carabid activity density and species richness were higher in the low input, 4-yr rotation compared with the conventionally managed, 2-yr rotation. There were greater differences in the temporal activity density and species richness of carabids among crops than within corn and soybean treatments managed with different agrichemical inputs and soil disturbance regimes. Detrended correspondence analysis showed strong yearly variation in carabid assemblages in all cropping treatments. The increase in carabid activity density and species richness observed in the 4-yr crop rotation highlights the potential benefits of diverse crop habitats for carabids and the possibility for managing natural enemies by manipulating crop rotations.

Amelioration of arterial properties with a perindopril-indapamide very-low-dose combination

BACKGROUND

Epidemiological studies have shown that increased arterial stiffness and wave reflections, major determinants of systolic and pulse pressure, are associated with morbidity and mortality. Therapeutic trials based on cardiovascular mortality have recently shown that reduction of systolic blood pressure (SBP) requires normalization of both large-artery stiffness and wave reflections.

AIMS

To compare the antihypertensive effects of the very-low-dose combination of perindopril (2 mg) and indapamide (0.625 mg) (one or two tablets per day) with the beta-blocking agent atenolol (50 mg; one or two tablets per day) in order to determine whether the combination decreased SBP and pulse pressure more than did atenolol, and whether this decrease occurred in relation to a reduction in arterial stiffness [aortic pulse wave velocity (PWV)] or a decrease in the intensity of, or delay in, wave reflections (augmentation index, measured by applanation tonometry) or a combination of both.

MATERIAL AND METHODS

This was a double-blind randomized study in 471 individuals with essential hypertension followed for 12 months. Arterial pressure was measured in the brachial artery (mercury sphygmomanometer) and in the carotid artery (applanation tonometry).

RESULTS

For the same reduction in diastolic blood pressure (DBP), the combination of perindopril and indapamide decreased brachial SBP and pulse pressure significantly more than did atenolol (adjusted differences between groups -6.2 +/- 1.5 and -5.5 +/- 1.0 mmHg, respectively; P < 0.001). This difference was even more pronounced for the carotid than for the brachial artery. Whereas both antihypertensive agents similarly decreased PWV, only the combination significantly attenuated wave reflections.

CONCLUSION

Normalization of SBP, pulse pressure and arterial function--a haemodynamic profile known to improve survival significantly in hypertensive populations at high cardiovascular risk--was achieved to a greater extent with a very-low-dose combination of perindopril and indapamide than with atenolol.

Improvement in blood pressure, arterial stiffness and wave reflections with a very-low-dose perindopril/indapamide combination in hypertensive patient: a comparison with atenolol

International guidelines recommend that antihypertensive drug therapy should normalize not only diastolic (DBP) but also systolic blood pressure (SBP). Therapeutic trials based on cardiovascular mortality have recently shown that SBP reduction requires normalization of both large artery stiffness and wave reflections. The aim of the present study was to compare the antihypertensive effects of the very-low-dose combination indapamide (0.625 mg) and perindopril (2 mg) (Per/Ind) with the beta-blocking agent atenolol (50 mg) to determine whether Per/Ind decreases SBP and pulse pressure (PP) more than does atenolol and, if so, whether this decrease is predominantly due to reduction of aortic pulse wave velocity (PWV) (automatic measurements) and reduction of wave reflections (pulse wave analysis, applanation tonometry). In a double-blind randomized study, 471 patients with essential hypertension were followed for 12 months. For the same DBP reduction, Per/Ind decreased brachial SBP (-6.02 mm Hg; 95% confidence interval, -8.90 to -3.14) and PP (-5.57; 95% confidence interval, -7.70 to -3.44) significantly more than did atenolol. This difference was significantly more pronounced for the carotid artery than for the brachial artery. Whereas the 2 antihypertensive agents decreased PWV to a similar degree, only Per/Ind significantly attenuated carotid wave reflections, resulting in a selective decrease in SBP and PP. The very-low-dose combination Per/Ind normalizes SBP, PP, and arterial function to a significantly larger extent than does atenolol, a hemodynamic profile that is known to improve survival in hypertensive populations with high cardiovascular risk.

Decision making and prostate cancer treatment selection: a review

OBJECTIVES

To review the issues surrounding decision making regarding prostate cancer treatment.

DATA SOURCES

Journal articles, abstracts, and selected findings from one prospective grounded theory research study.

CONCLUSIONS

Multiple factors are involved in the selection of prostate cancer treatment, such as individual disease-specific data, age, personal values, vicarious and personal cancer experiences, and the physician-patient relationship.

IMPLICATIONS FOR NURSING PRACTICE

Accurate information regarding each treatment option delivered by experts in their respective fields is necessary for informed decision making. A more multidisciplinary approach regarding discussion of treatment options is needed. Nurses play a pivotal role in facilitating discussion among family members and assisting patients to make a decision that balances their personal values with accurate information regarding treatment outcomes.

Expectant management of prostate cancer

OBJECTIVES

To discuss the role of expectant management in the treatment of clinically localized prostate cancer.

DATA SOURCES

Published research and review articles, textbooks, and pending research publications.

CONCLUSIONS

Expectant management is a viable option for the treatment of clinically localized prostate cancer in carefully selected men.

IMPLICATIONS FOR NURSING PRACTICE

Nursing personnel along with physicians must work together to develop coping strategies for these men to deal with the continual uncertainty of this treatment program.

Cutaneous paraneoplastic syndromes

Paraneoplastic syndromes are caused by hormones or other substances produced by cancer cells and may be the first sign of cancer. A wide range of paraneoplastic syndromes, including endocrine, neurologic, and cutaneous disorders, occurs in patients with cancer. More than 30 cutaneous paraneoplastic syndromes have been identified; this article reviews some of the more common syndromes--acanthosis nigricans, Paget's Disease, acquired ichthyosis, telangiectasia, hypertrichosis lanuginosa acquisita, erythroderma, Bazex's Syndrome, and necrotizing migratory erythema. When these syndromes are diagnosed during the course of a malignancy, professional caregivers may misinterpret them as indicative of metastatic disease or other disorders and patients may be misdiagnosed and not receive optimal treatment. Paraneoplastic syndromes also compromise quality of life by often causing skin impairment and discomfort. Therefore, nurses must be aware of the signs and symptoms of these cutaneous disorders and know how to care for patients with paraneoplastic syndromes.

Urinary incontinence as a factor in prostate cancer treatment selection

Urinary incontinence is a common adverse effect associated with treatment for early stage prostate cancer. The influence of this factor on treatment selection decisions by patients and their partners has been explored only minimally in the literature. Data regarding the actual incidence of incontinence associated with prostate cancer treatment are confusing because of the lack of standardized definitions of incontinence. Radical prostatectomy is associated with higher rates of urinary adverse effects than is radiation therapy. Brachytherapy appears to be associated with a low risk of incontinence, whereas cryosurgery is associated with significant urinary adverse effects. Including incontinence, urethral sloughing, and bladder neck obstruction. The influence of these adverse effects on decision making regarding prostate cancer treatment selection is difficult to ascertain. Research indicates that both men and their partners appear to have difficulty processing information presented to them regarding the probability of urinary adverse effects and the degree to which these adverse effects may have an impact on their daily lives.

Narrowing the options: the process of deciding on prostate cancer treatment

Prostate cancer is a pressing health concern in the United States and one surrounded by continual controversy. Currently there is no consensus regarding the efficacy of routine screening, nor has one treatment modality been demonstrated as superior. Patients and spouses are asked to choose from several options: radical prostatectomy, radiation therapy, or the "watch and wait" approach. A grounded theory design was used to examine the actual treatment decision-making process as it occurred over time among 18 newly diagnosed prostate cancer patients and their wives in western North Carolina. Couples were interviewed conjointly and individually to explore their perceptions of the decision process. All interviews were audiotaped, transcribed verbatim, and analyzed using content analysis techniques. Couples negotiated decisions through their common and unique personal and family histories, biases, and individual coping styles. They narrowed the options based on these factors. Most couples received their counseling regarding treatment options exclusively from the surgeon who narrowed the options based on age and physiologic status. Most couples chose surgery believing it to be the only treatment promising cure. Distinct misconceptions about radiation therapy were noted. Concern about potential side effects did not deter men from selecting surgery, although men and their wives differed in their willingness to accept treatment "at any cost." Information regarding potential for cure and risk of recurrence were highly important factors in the decision process. The decision was incomparable with any other life decisions the couples had faced.

Prostate cancer treatment decisions: a focus group exploration

PURPOSE/OBJECTIVES

To explore the decision-making process as retrospectively described by patients with prostate cancer and their spouses and to test the feasibility of a larger scale prospective examination of decision making in this same population.

DESIGN

A qualitative study using focus group methodology.

SAMPLE/SETTING

Twelve patients with prostate cancer and six spouses were recruited purposefully from a newly organized prostate cancer support group in an urban North Carolina community.

METHODS

Using an interview guide, an experienced facilitator conducted two 90-minute focus groups. Sessions were audiotaped, transcribed verbatim, and analyzed using thematic content analysis techniques.

MAIN RESEARCH VARIABLES

Decision making, prostate cancer treatment, spousal participation.

FINDINGS

Six themes were derived from the data: (a) Finding Out, (b) Prostate Specific Antigen Talk, (c) (Getting the Story, (d) Who Decides, (e) Treatment Options, and (f) Looking Back. The data corroborated American Cancer Society findings that national cancer resources are not being used effectively by this population and reinforced the need for a multidisciplinary approach to the management of prostate cancer.

CONCLUSIONS

Additional prospective studies are needed to explore the decision process from a family perspective. Studies focusing on the unique needs of older patients with prostate cancer and their spouses also are needed.

IMPLICATIONS FOR NURSING PRACTICE

Nurses must assess informal information sources and work toward a more comprehensive presentation of treatment options. Misconceptions about surgery and radiotherapy hamper informed decision making. Nurses are in a unique position to educate families regarding prostate cancer treatment options.