Classification system for primary care provider eConsults about medications for older adults with frailty.

BACKGROUND: Providing primary care for people with frailty can be challenging due to an increased risk of adverse outcomes and use of potentially inappropriate medications which may exacerbate characteristics of frailty. eConsult is a service where primary care providers can receive timely specialist advice for their patients through a secure web-based application. We aimed to develop a classification system to characterize medication-focused eConsult questions for older adults with frailty and assess its usability. METHODS: A classification system was developed and refined over three cycles of improvement through a cross-sectional study of 35 cases categorized as medication-focused from cases submitted in 2019 for patients aged 65 or older with frailty through the Champlain BASE eConsult service (Ontario, Canada). The final classification system was then applied to each case. RESULTS: The classification system contains 5 sections: (1) case descriptives; (2) intent and type of question; (3) medication recommendations and additional information in the response; (4) medication classification; and (5) potentially inappropriate medications. Among the 35 medication-focused cases, the most common specialties consulted were endocrinology (9 cases, 26%) and cardiology (5 cases, 14%). Medication histories were available for 29 cases (83%). Many patients were prescribed potentially inappropriate medications based on explicit tools (AGS Beers Criteria®, STOPPFall, Anticholinergic Cognitive Burden Scale, ThinkCascades) yet few consults inquired about these medications. CONCLUSION: A classification system to describe medication-related eConsult cases for patients experiencing frailty was developed and applied to 35 eConsult cases. It can be applied to more cases to identify professional development opportunities and enhancements for eConsult services.

Phylogenomics illuminates the phylogeny of flower weevils (Curculioninae) and reveals ten independent origins of brood-site pollination mutualism in true weevils.

Weevils are an unusually species-rich group of phytophagous insects for which there is increasing evidence of frequent involvement in brood-site pollination. This study examines phylogenetic patterns in the emergence of brood-site pollination mutualism among one of the most speciose beetle groups, the flower weevils (subfamily Curculioninae). We analysed a novel phylogenomic dataset consisting of 214 nuclear loci for 202 weevil species, with a sampling that mainly includes flower weevils as well as representatives of all major lineages of true weevils (Curculionidae). Our phylogenomic analyses establish a uniquely comprehensive phylogenetic framework for Curculioninae and provide new insights into the relationships among lineages of true weevils. Based on this phylogeny, statistical reconstruction of ancestral character states revealed at least 10 independent origins of brood-site pollination in higher weevils through transitions from ancestral associations with reproductive structures in the larval stage. Broadly, our results illuminate the unexpected frequency with which true weevils-typically specialized phytophages and hence antagonists of plants-have evolved mutualistic interactions of ecological significance that are key to both weevil and plant evolutionary fitness and thus a component of their deeply intertwined macroevolutionary success.

Improving care for elderly patients living with polypharmacy: protocol for a pragmatic cluster randomized trial in community-based primary care practices in Canada.

BACKGROUND: Elders living with polypharmacy may be taking medications that do not benefit them. Polypharmacy can be associated with elevated risks of poor health, reduced quality of life, high care costs, and persistently complex care needs. While many medications could be problematic, this project targets medications that should be deprescribed for most elders and for which guidelines and evidence-based deprescribing tools are available. These are termed potentially inappropriate prescriptions (PIPs) and are as follows: proton pump inhibitors, benzodiazepines, antipsychotics, and sulfonylureas. Implementation strategies for deprescribing PIPs in complex older patient populations are needed. METHODS: This will be a pragmatic cluster randomized controlled trial in community-based primary care practices across Canada. Eligible practices provide comprehensive primary care and have at least one physician that consents to participate. Community-dwelling patients aged 65 years and older with ten or more unique medication prescriptions in the past year will be included. The objective is to assess whether the intervention reduces targeted PIPs for these patients compared with usual care. The intervention, Structured Process Informed by Data, Evidence and Research (SPIDER), is a collaboration between quality improvement (QI) and research programs. Primary care teams will form interprofessional Learning Collaboratives and work with QI coaches to review electronic medical record data provided by their regional Practice Based Research Networks (PBRNs), identify areas of improvement, and develop and implement changes. The study will be tested for feasibility in three PBRNs (Toronto, Montreal, and Edmonton) using prospective single-arm mixed methods. Findings will then guide a pragmatic cluster randomized controlled trial in five PBRNs (Calgary, Winnipeg, Ottawa, Montreal, and Halifax). Seven practices per PBRN will be recruited for each arm. The analysis will be by intention to treat. Ten percent of patients who have at least one PIP at baseline will be randomly selected to participate in the assessment of patient experience and self-reported outcomes. Qualitative methods will be used to explore patient and physician experience and evaluate SPIDER's processes. CONCLUSION: We are testing SPIDER in a primary care population with complex care needs. This could provide a widely applicable model for care improvement. TRIAL REGISTRATION: Clinicaltrials.gov NCT03689049 ; registered September 28, 2018.

Deprescribing antihyperglycemic agents in older persons: evidence-based clinical practice guideline

OBJECTIVE: To develop an evidence-based guideline to help clinicians make decisions about when and how to safely taper, stop, or switch antihyperglycemic agents in older adults. METHODS: We focused on the highest level of evidence available and sought input from primary care professionals in guideline development, review, and endorsement processes. Seven clinicians (2 family physicians, 3 pharmacists, 1 nurse practitioner, and 1 endocrinologist) and a methodologist comprised the overall team; members disclosed conflicts of interest. We used a rigorous process, including the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach, for guideline development. We conducted a systematic review to assess evidence for the benefits and harms of deprescribing antihyperglycemic agents. We performed a review of reviews of the harms of continued antihyperglycemic medication use, and narrative syntheses of patient preferences and resource implications. We used these syntheses and GRADE quality-of-evidence ratings to generate recommendations. The team refined guideline content and recommendation wording through consensus and synthesized clinical considerations to address common front-line clinician questions. The draft guideline was distributed to clinicians and stakeholders for review and revisions were made at each stage. A decision-support algorithm was developed to accompany the guideline. RECOMMENDATIONS: We recommend deprescribing antihyperglycemic medications known to contribute to hypoglycemia in older adults at risk or in situations where antihyperglycemic medications might be causing other adverse effects, and individualizing targets and deprescribing accordingly for those who are frail, have dementia, or have a limited life expectancy. CONCLUSION: This guideline provides practical recommendations for making decisions about deprescribing antihyperglycemic agents. Recommendations are meant to assist with, not dictate, decision making in conjunction with patients.

Deprescribing proton pump inhibitors: evidence-based clinical practice guideline

OBJECTIVE: To develop an evidence-based guideline to help clinicians make decisions about when and how to safely taper or stop proton pump inhibitors (PPIs); to focus on the highest level of evidence available and seek input from primary care professionals in the guideline development, review, and endorsement processes. METHODS: Five health professionals (1 family physician, 3 pharmacists, and 1 gastroenterologist) and 5 nonvoting members comprised the overall team; members disclosed conflicts of interest. The guideline process included the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach, with a detailed evidence review in in-person, telephone, and online meetings. Uniquely, the guideline development process included a systematic review of PPI deprescribing trials and examination of reviews of the harm of continued PPI use. Narrative syntheses of patient preferences and resource-implication literature informed recommendations. The team refined guideline content and recommendation wording through consensus and synthesized clinical considerations to address common front-line clinician questions. The draft guideline was distributed to clinicians and then to health care professional associations for review and revisions made at each stage. A decision-support algorithm was developed in conjunction with the guideline. RECOMMENDATIONS: This guideline recommends deprescribing PPIs (reducing dose, stopping, or using "on-demand" dosing) in adults who have completed a minimum of 4 weeks of PPI treatment for heartburn or mild to moderate gastroesophageal reflux disease or esophagitis, and whose symptoms are resolved. The recommendations do not apply to those who have or have had Barrett esophagus, severe esophagitis grade C or D, or documented history of bleeding gastrointestinal ulcers. CONCLUSION: This guideline provides practical recommendations for making decisions about when and how to reduce the dose of or stop PPIs. Recommendations are meant to assist with, not dictate, decision making in conjunction with patients.

A statistical state dynamics approach to wall turbulence.

This paper reviews results obtained using statistical state dynamics (SSD) that demonstrate the benefits of adopting this perspective for understanding turbulence in wall-bounded shear flows. The SSD approach used in this work employs a second-order closure that retains only the interaction between the streamwise mean flow and the streamwise mean perturbation covariance. This closure restricts nonlinearity in the SSD to that explicitly retained in the streamwise constant mean flow together with nonlinear interactions between the mean flow and the perturbation covariance. This dynamical restriction, in which explicit perturbation-perturbation nonlinearity is removed from the perturbation equation, results in a simplified dynamics referred to as the restricted nonlinear (RNL) dynamics. RNL systems, in which a finite ensemble of realizations of the perturbation equation share the same mean flow, provide tractable approximations to the SSD, which is equivalent to an infinite ensemble RNL system. This infinite ensemble system, referred to as the stochastic structural stability theory system, introduces new analysis tools for studying turbulence. RNL systems provide computationally efficient means to approximate the SSD and produce self-sustaining turbulence exhibiting qualitative features similar to those observed in direct numerical simulations despite greatly simplified dynamics. The results presented show that RNL turbulence can be supported by as few as a single streamwise varying component interacting with the streamwise constant mean flow and that judicious selection of this truncated support or 'band-limiting' can be used to improve quantitative accuracy of RNL turbulence. These results suggest that the SSD approach provides new analytical and computational tools that allow new insights into wall turbulence.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'.

Caesarean section surgical techniques: 3 year follow-up of the CORONIS fractional, factorial, unmasked, randomised controlled trial.

BACKGROUND: The CORONIS trial reported differences in short-term maternal morbidity when comparing five pairs of alternative surgical techniques for caesarean section. Here we report outcomes at 3 years follow-up. METHODS: The CORONIS trial was a pragmatic international 2 × 2 × 2 × 2× 2 non-regular fractional, factorial, unmasked, randomised controlled trial done at 19 sites in Argentina, Chile, Ghana, India, Kenya, Pakistan, and Sudan. Pregnant women were eligible if they were to undergo their first or second caesarean section through a planned transverse abdominal incision. Women were randomly assigned by a secure web-based allocation system to one intervention from each of the three assigned pairs. All investigators, surgeons, and participants were unmasked to treatment allocation. In this follow-up study, we compared outcomes at 3 years following blunt versus sharp abdominal entry, exteriorisation of the uterus for repair versus intra-abdominal repair, single versus double layer closure of the uterus, closure versus non-closure of the peritoneum, and chromic catgut versus polyglactin-910 for uterine repair. Outcomes included pelvic pain; deep dyspareunia; hysterectomy and outcomes of subsequent pregnancies. Outcomes were assessed masked to the original trial allocation. This trial is registered with the Current Controlled Trials registry, number ISRCTN31089967. FINDINGS: Between Sept 1, 2011, and Sept 30, 2014, 13,153 (84%) women were followed-up for a mean duration of 3·8 years (SD 0·86). For blunt versus sharp abdominal entry there was no evidence of a difference in risk of abdominal hernias (adjusted RR 0·66; 95% CI 0·39-1·11). We also recorded no evidence of a difference in risk of death or serious morbidity of the children born at the time of trial entry (0·99, 0·83-1·17). For exteriorisation of the uterus versus intra-abdominal repair there was no evidence of a difference in risk of infertility (0·91, 0·71-1·18) or of ectopic pregnancy (0·50, 0·15-1·66). For single versus double layer closure of the uterus there was no evidence of a difference in maternal death (0·78, 0·46-1·32) or a composite of pregnancy complications (1·20, 0·75-1·90). For closure versus non-closure of the peritoneum there was no evidence of a difference in any outcomes relating to symptoms associated with pelvic adhesions such as infertility (0·80, 0·61-1·06). For chromic catgut versus polyglactin-910 sutures there was no evidence of a difference in the main comparisons for adverse pregnancy outcomes in a subsequent pregnancy, such as uterine rupture (3·05, 0·32-29·29). Overall, severe adverse outcomes were uncommon in these settings. INTERPRETATION: Although our study was not powered to detect modest differences in rare but serious events, there was no evidence to favour one technique over another. Other considerations will probably affect clinical practice, such as the time and cost saving of different approaches. FUNDING: UK Medical Research Council and the Department for International Development.

Caesarean section surgical techniques (CORONIS): a fractional, factorial, unmasked, randomised controlled trial.

BACKGROUND: Variations exist in the surgical techniques used for caesarean section and many have not been rigorously assessed in randomised controlled trials. We aimed to assess whether any surgical techniques were associated with improved outcomes for women and babies. METHODS: CORONIS was a pragmatic international 2×2×2×2×2 non-regular fractional, factorial, unmasked, randomised controlled trial that examined five elements of the caesarean section technique in intervention pairs. CORONIS was undertaken at 19 sites in Argentina, Chile, Ghana, India, Kenya, Pakistan, and Sudan. Each site was assigned to three of the five intervention pairs: blunt versus sharp abdominal entry; exteriorisation of the uterus for repair versus intra-abdominal repair; single-layer versus double-layer closure of the uterus; closure versus non-closure of the peritoneum (pelvic and parietal); and chromic catgut versus polyglactin-910 for uterine repair. Pregnant women were eligible if they were to undergo their first or second caesarean section through a planned transverse abdominal incision. Women were randomly assigned by a secure web-based number allocation system to one intervention from each of the three assigned pairs. All investigators, surgeons, and participants were unmasked to treatment allocation. The primary outcome was the composite of death, maternal infectious morbidity, further operative procedures, or blood transfusion (>1 unit) up to the 6-week follow-up visit. Women were analysed in the groups into which they were allocated. The CORONIS Trial is registered with Current Controlled Trials: ISRCTN31089967. FINDINGS: Between May 20, 2007, and Dec 31, 2010, 15 935 women were recruited. There were no statistically significant differences within any of the intervention pairs for the primary outcome: blunt versus sharp entry risk ratio 1·03 (95% CI 0·91-1·17), exterior versus intra-abdominal repair 0·96 (0·84-1·08), single-layer versus double-layer closure 0·96 (0·85-1·08), closure versus non-closure 1·06 (0·94-1·20), and chromic catgut versus polyglactin-910 0·90 (0·78-1·04). 144 serious adverse events were reported, of which 26 were possibly related to the intervention. Most of the reported serious adverse events were known complications of surgery or complications of the reasons for the caesarean section. INTERPRETATION: These findings suggest that any of these surgical techniques is acceptable. However, longer-term follow-up is needed to assess whether the absence of evidence of short-term effects will translate into an absence of long-term effects. FUNDING: UK Medical Research Council and WHO.

Balancing selection on MHC class I in wild brown trout Salmo trutta.

Evidence is reported for balancing selection acting on variation at major histocompatibility complex (MHC) in wild populations of brown trout Salmo trutta. First, variation at an MHC class I (satr-uba)-linked microsatellite locus (mhc1) is retained in small S. trutta populations isolated above waterfalls although variation is lost at neutral microsatellite markers. Second, populations across several catchments are less differentiated at mhc1 than at neutral markers, as predicted by theory. The population structure of these fish was also elucidated.

Deposition of continuous platinum shells on gold nanoparticles by chemical precipitation.

Continuous platinum shells consisting of ~5 atomic layers were deposited onto preformed gold seeds in aqueous medium by reducing hexachloroplatinic acid with ascorbic acid. By controlling the reduction kinetics of Pt(IV) species and the properties of the substrate, it was possible to ensure a slow and controlled deposition of platinum atoms onto the gold cores. Electrochemical evaluations revealed the presence of a compact platinum shell. The mass specific oxygen reduction activity of platinum in the AuPt core-shell nanoparticles was found to be four times higher than that of platinum black and comparable to that of polycrystalline bulk metal.

MHC-mediated spatial distribution in brown trout (Salmo trutta) fry.

Major histocompatibility complex (MHC) class I-linked microsatellite data and parental assignment data for a group of wild brown trout (Salmo trutta L.) provide evidence of closer spatial aggregation among fry sharing greater numbers of MHC class I alleles under natural conditions. This result confirms predictions from laboratory experiments demonstrating a hierarchical preference for association of fry sharing MHC alleles. Full-siblings emerge from the same nest (redd), and a passive kin association pattern arising from limited dispersal from the nest (redd effect) would predict that all such pairs would have a similar distribution. However, this study demonstrates a strong, significant trend for reduced distance between pairs of full-sibling fry sharing more MHC class I alleles reflecting their closer aggregation (no alleles shared, 311.5 ± (s.e.)21.03 m; one allele shared, 222.2 ± 14.49 m; two alleles shared, 124.9 ± 23.88 m; P<0.0001). A significant trend for closer aggregation among fry sharing more MHC class I alleles was also observed in fry pairs, which were known to have different mothers and were otherwise unrelated (ML-r = 0) (no alleles: 457.6 ± 3.58 m; one allele (422.4 ± 3.86 m); two alleles (381.7 ± 10.72 m); P<0.0001). These pairs are expected to have emerged from different redds and a passive association would then be unlikely. These data suggest that sharing MHC class I alleles has a role in maintaining kin association among full-siblings after emergence. This study demonstrates a pattern consistent with MHC-mediated kin association in the wild for the first time.

Mefloquine in the treatment of progressive multifocal leukoencephalopathy.

Mefloquine, an antimalarial medication with efficacy against JC virus, was used to treat progressive multifocal leukoencephalopathy. A 54-year-old woman with sarcoidosis presented with a progressive cerebellar syndrome. MRI showed lesions affecting the right cerebellum that progressed over time to the brainstem. JC virus was found in the cerebrospinal fluid (CSF), and brain biopsy confirmed the diagnosis of progressive multifocal leukoencephalopathy. Mefloquine 1000 mg/week was initiated 6 months after symptom onset. Clinical progression stopped immediately, and JC virus became undetectable in the CSF. No clinical or imaging evidence of disease progression has occurred over 20 months of follow-up. This is the first report of successful treatment of progressive multifocal leukoencephalopathy with mefloquine.

Shifts in expectations: evaluating physicians' perceptions as pharmacists become integrated into family practice.

The objective of this study was to measure how primary care family physicians perceived their own and pharmacists' contributions to medication processes as pharmacists become integrated into primary care group family practices. The 22- item Family Medicine Medication Use Processes Matrix was mailed to physicians in seven sites at the 3rd, 12th and 19th month of pharmacist integration. Paired sample t-tests for the third month results were conducted to compare perceptions between pharmacist and physician contributions. One way repeated measure ANOVA test was conducted to determine significant changes over time. Physicians initially perceived their own contributions to be significantly higher than pharmacists in three subscales: Diagnosis & Prescribing, Monitoring and Administration/Documentation and their own contributions to be significantly lower than the pharmacists in the Education subscale. Over time, physicians perceived increases in the pharmacists' contribution to the Diagnosis & Prescribing, Monitoring and Medication Review subscales and decreases in their own contribution to the Diagnosis & Prescribing and Education subscales. Changes in family physicians' perceptions of pharmacists' contribution demonstrate an initial underestimate of pharmacists' role in primary care family practice and a gradual recognition of expertise and competence. This may have led to increased comfort in sharing aspects of contribution to medication use processes.

Integrating family medicine and pharmacy to advance primary care therapeutics.

The prevalence of suboptimal prescribing of medications is well documented. Patients are often undertreated or not offered therapeutic treatments that are likely to confer benefit. As a result, drug-related hospital admissions are common and often preventable. Improvements to the health-care system are clearly needed in order to maximize the benefits that can be derived from medications. Many countries are changing their primary health-care systems to improve the quality of health-care delivery. One main transformation is the use of multidisciplinary care teams to provide care in a coordinated manner often from the same location or by using the common medical record of the patients. It has been demonstrated that pharmacists can improve prescribing, reduce health-care utilization and medication costs, and contribute to clinical improvements in many chronic medical conditions, such as cardiovascular disease, diabetes, and psychiatric illness. However, the effect of integrating a pharmacist providing general services into a primary care group has not been extensively studied. The Integrating Family Medicine and Pharmacy to Advance Primary Care Therapeutics (IMPACT) project was designed to provide a real-world demonstration of the feasibility of integrating the pharmacist into primary care office practice. This article provides a description of the IMPACT project participants; the IMPACT practice model and the concepts incorporated in its development; some initial results from the program evaluation; sustainability of the model; and some reflections on the implementation of the practice model.

The MRC CRASH Trial: study design, baseline data, and outcome in 1000 randomised patients in the pilot phase.

OBJECTIVES: To test the design and feasibility of a large scale multicentre randomised controlled trial evaluating the efficacy and safety of a high dose corticosteroid infusion after head injury. To assess whether large numbers of patients could be enrolled and treated within eight hours from injury and then followed up at six months. METHODS: Randomised placebo controlled multicentre trial of a 48 hour corticosteroid infusion after significant head injury. All head injured adults who were observed while in hospital to have GCS of 14 or less (out of a maximum score of 15), and who were within eight hours of the injury, were eligible for trial entry. Analysis of baseline and outcome data (for both treatment groups combined) for 1000 patients enrolled in the pilot phase of the MRC CRASH Trial. RESULTS: Fifty two hospitals in 14 countries participated in the pilot phase, recruiting an average of one patient per hospital per month. Of the 1000 randomised patients, 330 (33%) had mild head injury, 289 (29%) had moderate head injury, and 381 (38%) had severe head injury. Seven hundred and nine (71%) patients were randomised within three hours of injury. Outcome at two weeks from injury was known for 991 (99%) patients, of whom 170 (17%) patients died. At the time of writing, six month follow up for the first 500 patients was nearly complete. Vital status was known for 465 (93%) of the 500 patients, of whom 97 (21%) had died. Functional status based on the Glasgow Outcome Scale was known for 438 (88%) of the 500 patients: 21% were dead, 17% were severely disabled, 22% were moderately disabled, and 34% had made a good recovery. CONCLUSIONS: The trial procedures proved practicable and a wide variety of patients were recruited in the emergency department within eight hours of injury. Using simple outcome measures, large numbers of patients can be successfully followed up.

Attractive intramolecular edge-to-face aromatic interactions in flexible organic molecules.

Recent X-ray crystallographic and NMR evidence indicates that relatively weak intramolecular edge-to-face interactions between aromatic rings can affect or determine the conformation of organic molecules in the solid state and in solution. Experimental estimates indicate that these interactions are energetically attractive by ca. 1.5 kcal mol(-1) but disfavored in solution by entropic factors due to the restricted internal mobility. Hence, these interactions are more manifest at low temperature in solution or in crystal structures where conformational entropy effects are negligible.

Surgical palliation at a cancer center: incidence and outcomes.

HYPOTHESIS: Surgical intervention in palliative care is common; however, the indications, risks, and outcomes are not well described. DESIGN: Retrospective review of surgical cases during a 1-year period with a minimum 1-year survival update. SETTING: A National Cancer Institute-designated comprehensive cancer center. PATIENTS: Patients with a cancer diagnosis undergoing operative procedures. MAIN OUTCOME MEASURES: Number of palliative surgeries and analysis of length of stay, morbidity, and mortality. RESULTS: Palliative surgeries comprised 240 (12.5%) of 1915 surgical procedures. There were 170 major and 70 minor procedures. Neurosurgical (46.0%), orthopedic (31.3%), and thoracic (21.5%) surgical procedures were frequently palliative. The most common primary diagnoses were lung, colorectal, breast, and prostate cancers. Length of hospital stay was 12.4 days (range, 0-99 days), with 21.3% of procedures performed on an outpatient basis. The 30-day mortality was 12.2%, with 5 patients dying within 5 days of their procedure. The overall mortality was 23.3% (56/240). Mortality for surgical procedures classified as major was 21.9% (44/170) and 10.0% (7/70) for those classified as minor (Fisher exact test, P<.01). CONCLUSIONS: Significant numbers of palliative procedures are performed at our cancer center. Overall morbidity and mortality were high; however, a significant number of patients had short hospital stays and low morbidity. Palliative surgery should remain an important part of end-of-life care. Patients and their families must be aware of the high risks and understand the clear objectives of these procedures.

Evolutionary assembly of the milkweed fauna: cytochrome oxidase I and the age of Tetraopes beetles.

The insects that feed on the related plant families Apocynaceae and Asclepiadaceae (here collectively termed "milkweeds") comprise a "component community" of highly specialized, distinctive lineages of species that frequently sequester toxic cardiac glycosides from their host plants for defense against predators and are thus often aposematic, advertising their consequent unpalatability. Such sets of specialized lineages provide opportunities for comparative studies of the rate of adaptation, diversification, and habitat-related effects on molecular evolution. The cerambycid genus Tetraopes is the most diverse of the new world milkweed herbivores and the species are generally host specific, being restricted to single, different species of Asclepias, more often so than most other milkweed insects. Previous work revealed correspondence between the phylogeny of these beetles and that of their hosts. The present study provides analyses of near-complete DNA sequences for Tetraopes and relatives that are used to establish a molecular clock and temporal framework for Tetraopes evolution with their milkweed hosts.

The evolution of agriculture in beetles (Curculionidae: Scolytinae and Platypodinae).

Beetles in the weevil subfamilies Scolytinae and Platypodinae are unusual in that they burrow as adults inside trees for feeding and oviposition. Some of these beetles are known as ambrosia beetles for their obligate mutualisms with asexual fungi--known as ambrosia fungi--that are derived from plant pathogens in the ascomycete group known as the ophiostomatoid fungi. Other beetles in these subfamilies are known as bark beetles and are associated with free-living, pathogenic ophiostomatoid fungi that facilitate beetle attack of phloem of trees with resin defenses. Using DNA sequences from six genes, including both copies of the nuclear gene encoding enolase, we performed a molecular phylogenetic study of bark and ambrosia beetles across these two subfamilies to establish the rate and direction of changes in life histories and their consequences for diversification. The ambrosia beetle habits have evolved repeatedly and are unreversed. The subfamily Platypodinae is derived from within the Scolytinae, near the tribe Scolytini. Comparison of the molecular branch lengths of ambrosia beetles and ambrosia fungi reveals a strong correlation, which a fungal molecular clock suggests spans 60 to 21 million years. Bark beetles have shifted from ancestral association with conifers to angiosperms and back again several times. Each shift to angiosperms is associated with elevated diversity, whereas the reverse shifts to conifers are associated with lowered diversity. The unusual habit of adult burrowing likely facilitated the diversification of these beetle-fungus associations, enabling them to use the biomass-rich resource that trees represent and set the stage for at least one origin of eusociality.