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PubMed2000

Resource use and survival of patients hospitalized with congestive heart failure: differences in care by specialty of the attending physician. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments.

BACKGROUND: Previous studies suggest that specialty care is more costly but may produce improved outcomes for patients with acute cardiac illnesses. OBJECTIVE: To determine whether patients with congestive heart failure who are cared for by cardiologists experienced differences in costs, care patterns, and survival compared with patients of generalists. DESIGN: Prospective cohort study. SETTING: 5 U.S. teaching hospitals between 1989 and 1994. PATIENTS: 1298 patients hospitalized with an exacerbation of congestive heart failure. MEASUREMENTS: Hospital costs; average daily Therapeutic Intervention Scoring System (TISS) score; and survival censored at 30, 180, and 365 days and 31 December 1994. RESULTS: Compared with patients of generalists, patients of cardiologists were younger (mean age, 63.3 and 71.4 years; P < 0.001) and had lower Acute Physiology Scores at the time of admission (35.1 and 36.7; P < 0.001) but were more likely to have a history of ventricular arrhythmias (21.0% and 10.2%; P < 0.001). At 6 months, 201 (27%) patients of cardiologists and 149 (27%) patients of generalists had died. After adjustment for sociodemographic characteristics and severity of illness, patients of cardiologists incurred costs that were 42.9% (95% CI, 27.8% to 59.8%) higher and average daily TISS scores that were 2.83 points (CI, 1.96 to 3.68 points) higher than those of patients of generalists. Patients of cardiologists were more likely to undergo right-heart catheterization (adjusted odds ratio, 2.9 [CI, 1.7 to 4.9]) or cardiac catheterization (adjusted odds ratio, 3.9 [CI, 2.4 to 6.2]) and had higher odds for transfer to an intensive care unit and electrocardiographic monitoring. Adjusted survival did not differ significantly between groups at 30 days; however, there was a trend toward improved survival among patients of cardiologists at 1 year (adjusted relative hazard, 0.82 [CI, 0.65 to 1.04]) and at maximum follow-up (adjusted relative hazard, 0.80 [CI, 0.66 to 0.96]). CONCLUSIONS: In this observational study of patients hospitalized with congestive heart failure, cardiologist care was associated with greater costs and resource use and no difference in survival at 30 days of follow-up. Whether the trend toward better survival at longer follow-up represents differences in care or unadjusted illness severity is uncertain.

Adult↗
PubMed2001

Specialty of principal care physician and Medicare expenditures in patients with coronary artery disease: impact of comorbidity and severity.

OBJECTIVE: To explore differences in expenditures for elderly patients with acute and chronic coronary artery disease according to the specialty of the principal care physician. STUDY DESIGN: Retrospective analysis of Medicare claims. PATIENTS AND METHODS: A total of 250,514 patients with coronary artery disease (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 410-414) were drawn from a national random sample of 1992 Medicare expenditures. Patients were classified by the physician type with the highest number of Medicare Part B outpatient claims into a cardiologist group and a generalist group. The outcome was mean total expenditures, stratifying (1) by comorbidity as measured by the modified Charlson Index and (2) by severity defined as the proportion of patients with acute myocardial infarction or unstable angina. RESULTS: Those patients in the cardiologist group had lower comorbidity and higher severity than those in the generalist group. Overall mean expenditures were significantly higher for the cardiologist group than for the generalist group ($7658 vs $6047; P < .001). These differences in mean expenditures were evident at each level of comorbidity. However, when stratified by severity of diagnosis, differences were seen predominantly in those with acute diagnoses. For those with either acute myocardial infarction or unstable angina, the mean expenditures were higher for the cardiologist group than for the combined generalist group ($15,378 vs $12,260; P < .001); however, the mean expenditures for those with only chronic conditions were similar ($4856 vs $4745; P = .53). CONCLUSION: Expenditures were higher when cardiologists were the principal care physicians treating patients with acute disease but not chronic disease.

Acute Disease↗
PubMed2001

What does family practice need to do next? A cross-generational view.

BACKGROUND AND OBJECTIVES: This paper presents a 60-year view of family practice, including its first 30 years and best projections for its next 30 years as a discipline and field of practice. METHODS: An objective cross-generational approach was taken based on available evidence. RESULTS: Five lessons are drawn from the past 30 years: (1) Neither medical education, medical practice, nor the health care system have been reformed by family medicine. (2) Family practice remains but one of several options for primary care. (3) The generalist-specialist ratio has shifted farther to specialists since 1970. (4) The United States is unique among Western industrialized nations in having multiple generalist specialties. (5) The three primary care specialties are on parallel but separate courses. The health care system is now very different from that of 1970, as a result of managed care; increased burden of chronic illness in an aging population; de-emphasis of hospital care; proliferation of primary care providers; increased emphasis on shared decision making with patients, cost-effectiveness, and value of health care services; and advances in information and communication technology. CONCLUSIONS: The following course changes are recommended for family practice: (1) Embrace new paradigms of care (eg, evidence-based medicine, population-based care, chronic disease management). (2) Modify practice style and redesign systems of care. (3) Embrace further differentiation within family practice. (4) Reassess and revise educational programs at all levels. (5) Increase emphasis on practice-based research and expansion of clinical electronic databases. (6) Explore feasibility of a unified generalist discipline through new alliances with other primary care specialties. (7) Build organizational and political strength through alliances in advocating for structural change of the health care system to include universal coverage and a generalist primary care physician for all Americans.

Delivery of Health Care↗
PubMed2002

Effect of a second-year primary care preceptorship on medical students' career plans.

BACKGROUND: Preceptorships with community physicians have been incorporated into medical curricula to foster interest in generalist careers. An evaluation of our preceptorship program was undertaken to determine this influence. METHODS: Students were asked about career interests before and after a second-year community preceptorship. When graduating, those students entering primary-care residencies were surveyed to validate whether they planned to become generalist or specialist. Associations between career choice at graduation and career interest before and after the preceptorship were examined. RESULTS: Of 73 students who maintained a generalist career plan after the community preceptorship, 57 (78%) continued with the same at graduation. After the preceptorship, 70 students reported a change in career interest toward generalism, compared with 9 who reported an interest in specialism. A significant relationship was found between career interest change and career choice at graduation. CONCLUSION: Our community preceptorship had a modest impact in stimulating students to consider generalist careers.

Career Choice↗
PubMedDate not supplied

Knowledge, attitude, and outlook toward dentistry: their affect on sealant use and other related variables.

The dentist's knowledge about sealants, his attitude about the efficacy, safety, and cost effectiveness of sealants, and his general outlook towards dentistry as a profession were examined in a recent nationwide study of sealant use. Thirty-five hundred general dentists and 500 pediatric dentists were surveyed by a mail questionnaire with a response rate of 37.6% for generalists and 61.2% for pediatric dentists. Numerous moderate correlations were found. Both groups' Knowledge and Attitude scale scores were moderately correlated with sealant use as measured by the respondents' estimation of the percentage of their patients, age 18 and under, receiving sealants. Moderate correlations for both dentist groups also surfaced between Attitude and Knowledge as well as Attitude and Outlook but not between Knowledge and Outlook. Attitude in both groups correlated moderately with respondent scales entitled Preventive Orientation, Patient Influence, and Auxiliary Factors. For generalists, knowledge also correlated moderately with Sealant Awareness and Patient Influence while, for pediatric dentists, knowledge correlated moderately with Patient Influence only. While there was no significant difference between generalist and pediatric dentist outlook scale scores, pediatric dentists showed a significantly more positive attitude and greater knowledge about sealants than did generalists. It was suggested, therefore, that improvement of practitioners attitude and knowledge about sealants might influence sealant use.

Attitude of Health Personnel↗
PubMed1995

California physicians' willingness to care for the poor.

Although generalist physicians appear to be more likely than specialists to provide care for poor adult patients, they may still perceive financial and nonfinancial barriers to caring for these patients. We studied generalist physicians' attitudes toward caring for poor patients using focus groups and used the results to design a survey that tested the generalizability of the focus group findings. The focus groups included a total of 24 physicians in 4 California communities; the survey was administered to a random sample of 177 California general internists, family physicians, and general practitioners. The response rate was 70%. Of respondents, 77% accepted new patients with private insurance; 31% accepted new Medicaid patients, and 43% accepted new uninsured patients. Nonwhite physicians were more likely to care for uninsured and Medicaid patients than were white physicians. In addition to reimbursement, nonfinancial factors played an important role in physicians' decisions not to care for Medicaid or uninsured patients. The perception of an increased risk of being sued was cited by 57% of physicians as important in the decision not to care for Medicaid patients and by 49% for uninsured patients. Patient characteristics such as psychosocial problems, being ungrateful for care, and noncompliance were also important. Poor reimbursement was cited by 88% of physicians as an important reason not to care for Medicaid patients and by 77% for uninsured patients. Policy changes such as universal health insurance coverage and increasing the supply of generalist physicians may not adequately improve access to care unless accompanied by changes that address generalist physicians' financial and nonfinancial concerns about providing care for poor patients.

Adult↗
PubMed1996

Initial community site development for first--and second-year medical students.

BACKGROUND: Many medical schools are planning community-based experiences for preclinical students. As part of a generalist physician initiative, the University of Texas Medical Branch in Galveston placed all 200 first-year medical students in generalists' offices in a new course, called the "Community Continuity Experience." METHODS: Driven by significant time, class size, and geographic constraints, a process managed by the local Area Health Education Center was formulated for identifying and developing potential sites. The final process included identification of candidate generalist sites, departmental participation, and a detailed site assessment. The individual office nurses were the focus of site development activities. RESULTS: Feedback indicated that having office nurses serve as site facilitators was effective, and a key enabling strategy was having a nurse site coordinator serve as a single point of contact for all the sites. The students expressed positive views of the site experience and an interest in assignment, rather than student choice, for site allocation. CONCLUSIONS: Important components of site development for such a new course are development of an accurate database of available generalist community faculty, a methodical site selection process, an early orientation for all involved, and consideration of nonphysician site facilitators during the start-up phase.

Ambulatory Care↗
PubMedDate not supplied

Who needs a general physician?

OBJECTIVES: To determine the opinions of general practitioners (GPs) on requirements for a general medical service, and whether doctors themselves, when ill, prefer admission under a generalist or a specialist. METHODS AND SUBJECTS: One questionnaire was distributed to 100 GPs and a second questionnaire to 144 doctors in both general and hospital practice. CONCLUSIONS: Among physicians debate about the role of generalists has focussed on their emergency workload, but general practitioners also see an important need for generalists in the outpatient clinic. General practitioners recognise the necessity of increasing specialisation, but are concerned that it is leading some physicians to practise as 'partialists'. Both of these findings have implications for the training of junior physicians and the continuing education of consultants. The survey also revealed that if they themselves were taken ill, consultants were slightly more likely to prefer admission under the care of a specialist, whilst most GPs would prefer admission under a generalist.

Family Practice↗
PubMed1999

Internal medicine-pediatrics combined residency graduates: what are they doing now? Results of a survey.

BACKGROUND: While the number of internal medicine-pediatrics (med/peds) residency training programs has increased considerably in the past decade, questions continue to be raised about career paths of the graduates of these programs. It is uncertain whether med/peds graduates follow a generalist career path and whether they continue to practice both specialties. OBJECTIVE: To determine the career outcomes of graduates of med/peds residency programs. DESIGN: A survey questionnaire of graduates of med/peds residency programs. METHODS: The computer databases of the American Board of Pediatrics and the American Board of Internal Medicine were used to identify 1482 individuals who had completed training in combined med/peds residency programs between 1986 and 1995 and who had applied to either board for certification. The survey questionnaire was mailed to all graduates identified. MAIN OUTCOME MEASURES: Time spent in professional activity (patient care, teaching, administration, and research), site of principal clinical activity, ages of the patient population, types of hospital privileges, practice organization, subspecialty activity, night and weekend coverage arrangements, community size of practice, involvement in teaching, and membership in professional organizations. RESULTS: Of the total group of 1482 graduates, 87.3% are certified by the American Board of Internal Medicine, 91.3% by the American Board of Pediatrics, and 81.6% by both boards. The survey was completed by 1005 graduates (67.8%). The principal activity of almost 70% of the graduates was direct patient care. Most graduates cared for patients of all ages. More than half of all respondents noted that their principal clinical site is a community office practice. Eighty-five percent managed patients who require hospitalization. Approximately 50% of respondents had a medical school appointment. CONCLUSIONS: This study, the largest survey to date of med/peds graduates, provides strong evidence that most med/peds graduates are practicing generalists who care for adults and children. In addition, the fact that 80% of graduates achieve dual board certification suggests that these physicians are well qualified to care for the spectrum of health care needs of children and adults. Because the changing US health care system mandates a strong primary care base, these physicians will play a small but important role in providing high-quality generalist care.

Adult↗
PubMed1997

Current positions of graduates of internal medicine-pediatrics training programs.

OBJECTIVE: To determine what positions graduates of internal medicine-pediatrics programs currently hold. DESIGN: A survey of the program directors of residencies in internal medicine-pediatrics. PARTICIPANTS: Program directors of the 85 internal medicine-pediatrics training programs listed in the 1993-1994 Graduate Medical Education Directory. MAIN OUTCOME MEASURES: A 1-page survey that described the current positions of trainees graduating between 1987 and 1993. RESULTS: Seventy-four (87%) of the 85 program directors completed the survey. Of the 708 graduates reported on, 68% were practicing as generalists. The generalists of this cohort (n = 480) were primarily in private practice settings (n = 390, 81%) and most were practicing internal medicine-pediatrics (n = 416, 85%). Only 12% of the generalists had chosen to practice either pediatrics or internal medicine. Twenty-one percent of the total graduates had entered subspecialty training. CONCLUSIONS: To our knowledge, the sample of 708 graduates is the largest survey of graduates of internal medicine-pediatrics programs to date and shows that 68% of graduates are practicing in primary care fields. Graduates of internal medicine-pediatrics programs should be considered as an important source of primary care physicians.

Education↗
PubMed2002

Determinants of patient satisfaction in chronic illness.

OBJECTIVE: To determine whether primary care provided by generalists versus subspecialists resulted in different levels of patient satisfaction among persons with chronic illness. METHODS: A survey containing the Primary Care Provider Questionnaire and the Health Status Questionnaire (HSQ) was mailed to 2 population-based cohorts of patients with rheumatoid arthritis (RA) or diabetes mellitus (DM). All subjects were at least 35 years old and Rochester, Minnesota residents. Descriptive statistics, Spearman correlation coefficients, and multiple regression models were used to describe and compare the determinants of patient satisfaction. RESULTS: A total of 86 people (74% female) with RA and 208 people (56% male) with DM responded to the survey. Age range was 41-95 years and median disease duration was 8.7 years (RA) and 13.0 years (DM). Most patients described their health as fair or good. After adjusting for sex differences, RA patients were more likely than DM patients to report having a specialist as their primary care doctor. RA patients, whether reporting seeing a specialist or a generalist, had comparable HSQ physical health, mental health, social functioning, vitality, and bodily pain scores. DM patients seeing a specialist had more bodily pain and poorer physical functioning than those seeing a generalist. Across both chronic illnesses and physician specialties, median scores for patient satisfaction ranged from 17-18 for overall satisfaction (maximum 20); 30-33 for interpersonal skills (maximum 35); 23-26 for technical quality (maximum 30); and 20 for access to care (maximum 25). Multiple linear regression models revealed that 6.8-7.3% of the variation in satisfaction could be explained by HSQ scores, patient demographics, and physician specialty. CONCLUSION: Both RA and DM patients were highly satisfied with their care, regardless of the specialty of the provider. Physician specialty, patient demographics, and HSQ scores explained only a small proportion in the variation in satisfaction. These findings point to the need for additional research to further elucidate the determinants of patient satisfaction.

Adult↗
PubMed1996

Pollinator Foraging Strategies in Mixed Floral Arrays: Density Effects and Floral Constancy

The profitability of any foraging strategy may be in part dependent on the number of foragers adopting it, and so it can be viewed mathematically as a "game." We explore here the implications of a game-theoretic model of pollinators foraging on a mixed array of two flower species, with individual pollinators either specializing on one or the other, or else acting as generalists. We further allow for the possibility of specialist advantages in foraging efficiency. The predicted mixture of pollinator behavioral strategies depends on the overall floral density and the relative densities of the two flower species. Where floral resources are scarce, pollinators should behave as generalists whereas when resources are superabundant, specialization on the single most profitable flower type (all else being equal, the commonest one) is favored. At intermediate floral densities, a mix of floral specializations (floral constancy) is favored, so long as the rarer flower's density does not fall below some critical minimum level. Where the rarer flower is too rare, a mixture of generalists and common-species specialists is favored. Rare flowers are at a reproductive disadvantage in all cases, but their relative success is highest where their pollinators are flower constant.

Journal Article↗
PubMed2003

Utilization of preoperative urodynamic investigations by gynecologists who frequently operate for female urinary incontinence.

Our objective was to determine the availability and utilization of urodynamic investigations by gynecologists in the preoperative evaluation of women with urinary incontinence. Gynecologists in the UK, USA, Australia, New Zealand and Canada were asked what urodynamic investigations were required for four clinical scenarios. Analysis was restricted to frequent operators. Urodynamic investigations were available to 70% of frequent operators. For uncomplicated stress incontinence, cystometry was utilized by 72% of subspecialists and 44% of generalists ( P<0.001) who had access to urodynamic investigations. For stress incontinence and straining to void, uroflowmetry was utilized by 73% of subspecialists and 46% of generalists ( P<0.001) who had access to urodynamic investigations. We concluded that many gynecologists who frequently operate for female urinary incontinence do not have access to urodynamic investigations or do not utilize urodynamic investigations, or utilize investigations in a way that may be inadequate for the clinical problem. There are differences in utilization between subspecialists and generalists that are not explained by access. These observations could be explained by poor understanding or a lack of belief in the value of urodynamic investigations.

Aged↗
PubMed2005

Woodrat (Neotoma) herbivores maintain nitrogen balance on a low-nitrogen, high-phenolic forage, Juniperus monosperma.

The acquisition of adequate quantities of nitrogen is a challenge for herbivorous vertebrates because many plants are in low nitrogen and contain secondary metabolites that reduce nitrogen digestibility. To investigate whether herbivores maintain nitrogen balance on plant diets low in nitrogen and high in secondary compounds, we studied the effect of juniper (Juniperus monosperma) ingestion on the nitrogen balance of two species of herbivorous woodrats (Neotoma stephensi and N. albigula). These woodrat species feed on the foliage of juniper: N. stephensi is a juniper specialist, whereas N. albigula is a generalist that incorporates some juniper in its diet. Based on the nitrogen contents of the natural diets of these woodrats, we predicted that the generalist would be in negative nitrogen balance on a juniper diet whereas the specialist would not be affected. We found that both species of woodrat had low-nitrogen requirements (334.2 mg N/kg0.75/day) and that a diet of 50% juniper did not result in negative nitrogen balance for either species. However, excretion patterns of nitrogen were altered; on the 50% juniper diet, fecal nitrogen losses increased approximately 38% and urinary nitrogen losses were half that of the control diet. The results suggest that absorption and detoxification of juniper secondary compounds may be more important for restricting juniper intake by the generalist than nitrogen imbalance.

Analysis of Variance↗
PubMed2003

Reproductive barriers between congeneric monogenean parasites (Dactylogyrus: Monogenea): attachment apparatus morphology or copulatory organ incompatibility?

Morphometrical parameters of the attachment apparatus and copulatory organs of 52 Dactylogyrus species parasitizing 17 species of cyprinid fishes were analysed to test for the existence of reproductive barriers among congeneric species. The minimal spanning tree (MST) method was applied in the analyses. The position of "real" parasite communities, based on (1) observed infracommunities, (2) a checklist of parasites for a given host in the morphological space, was compared to the position of randomly generated communities using all Dactylogyrus species. The distribution of species similarity within infracommunities (using both attachment and copulatory measurements) was not significantly different from that obtained by simulation, and this trend was similar for both the checklist and observed infracommunities. When real infracommunities were separated according to host specificity (specialists versus generalists), we found differences reflecting similarities in the shapes of attachment and copulatory organs. Within specialists, more similarities in the shape of the attachment apparatus can be found than within generalists, whereas the similarity in copulatory organ shape seems to be random. When generalists are considered, parasite infracommunities with the greater differences in attachment apparatus are also more different in terms of the shape of their copulatory apparatus. We conclude that specialist parasites possess more similarity in attachment apparatus due to specialisation to their host, whereas the species similarity in copulatory organs within infracommunities exhibits a random pattern, but with the copulatory organs being more variable than the attachment apparatus (which may be due to reproductive isolation). The morphology of the copulatory apparatus seems not to be the single factor explaining reproductive isolation among species.

Animals↗
PubMed2003

An examination of scale of assessment, logging and ENSO-induced fires on butterfly diversity in Borneo.

The impact of disturbance on species diversity may be related to the spatial scales over which it occurs. Here I assess the impact of logging and ENSO (El Niño Southern Oscillation) -induced burning and forest isolation on the species richness (477 species out of more than 28,000 individuals) and community composition of butterflies and butterfly guilds using small (0.9 ha) plots nested within large (450 ha) landscapes. The landscapes were located in three habitat classes: (1) continuous, unburned forest; (2) unburned isolates surrounded by burned forest; and (3) burned forest. Plots with different logging histories were sampled within the two unburned habitat classes, allowing for independent assessment of the two disturbance factors (logging and burning). Disturbance within habitat classes (logging) had a very different impact on butterfly diversity than disturbance among habitat classes (due to ENSO-induced burning and isolation). Logging increased species richness, increased evenness, and lowered dominance. Among guilds based on larval food plants, the species richness of tree and herb specialists was higher in logged areas but their abundance was lower. Both generalist species richness and abundance was higher in logged areas. Among habitat classes, species richness was lower in burned forest and isolates than continuous forest but there was no overall difference in evenness or dominance. Among guilds, generalist species richness was significantly lower in burned forest and isolates than continuous forest. Generalist abundance was also very low in the isolates. There was no difference among disturbance classes in herb specialist species richness but abundance was significantly higher in the isolates and burned forest than in continuous forest. Tree specialist species richness was lower in burned forest than continuous forest but did not differ between continuous forest and isolates. The scale of assessment proved important in estimating the impact of disturbance on species richness. Within disturbance classes, the difference in species richness between primary and logged forest was more pronounced at the smaller spatial scale. Among disturbance classes, the difference in species richness between continuous forest and isolates or burned forest was more pronounced at the larger spatial scale. The lower levels of species richness in ENSO-affected areas and at the larger (landscape) spatial scale indicate that future severe ENSO events may prove one of the most serious threats to extant biodiversity.

Animals↗
PubMed2004

Effects of elevated atmospheric CO2 on the nutritional ecology of C3 and C4 grass-feeding caterpillars.

It is plausible that the nutritional quality of C3 plants will decline more under elevated atmospheric CO2 than will the nutritional quality of C4 plants, causing herbivorous insects to increase their feeding on C3 plants relative to C4 plants. We tested this hypothesis with a C3 and C4 grass and two caterpillar species with different diet breadths. Lolium multiflorum (C3) and Bouteloua curtipendula (C4) were grown in outdoor open top chambers at ambient (370 ppm) or elevated (740 ppm) CO2. Bioassays compared the performance and digestive efficiencies of Pseudaletia unipuncta (a grass-specialist noctuid) and Spodoptera frugiperda (a generalist noctuid). As expected, the nutritional quality of L. multiflorum changed to a greater extent than did that of B. curtipendula when grown in elevated CO2; levels of protein (considered growth limiting) declined in the C3 grass, while levels of carbohydrates (sugar, starch and fructan) increased. However, neither insect species increased its feeding rate on the C3 grass to compensate for its lower nutritional quality when grown in an elevated CO2 atmosphere. Consumption rates of P. unipuncta and S. frugiperda were higher on the C3 grass than the C4 grass, the opposite of the result expected for a compensatory response to the lower nutritional quality of the C4 grass. Although our results do not support the hypothesis that grass-specialist insects compensate for lower nutritional quality by increasing their consumption rates more than do generalist insects, the performance of the specialist was greater than that of the generalist on each grass species and at both CO2 levels. Mechanisms other than compensatory feeding, such as increased nutrient assimilation efficiency, appear to determine the relative performance of these herbivores. Our results also provide further evidence against the hypothesis that C4 grasses would be avoided by insect herbivores because a large fraction of their nutrients is unavailable to herbivores. Instead, our results are consistent with the hypothesis that C4 grasses are poorer host plants primarily because of their lower nutrient levels, higher fiber levels, and greater toughness.

Air↗
PubMed2006

Increased chemical resistance explains low herbivore colonization of introduced seaweed.

The success of introduced species is often attributed to release from co-evolved enemies in the new range and a subsequent decreased allocation to defense (EICA), but these hypotheses have rarely been evaluated for systems with low host-specificity of enemies. Here, we compare herbivore utilization of the brown seaweed, Fucus evanescens, and its coexisting competitors both in its native and new ranges, to test certain predictions derived from these hypotheses in a system dominated by generalist herbivores. While F. evanescens was shown to be a preferred host in its native range, invading populations supported a less diverse herbivore fauna and it was less preferred in laboratory choice experiments with important herbivores, when compared to co-occurring seaweeds. These results are consistent with the enemy release hypothesis, despite the fact that the herbivore communities in both regions were mainly composed of generalist species. However, in contrast to the prediction of EICA, analysis of anti-grazing compounds indicated a higher allocation to defense in introduced compared to native F. evanescens. The results suggest that the invader is subjected to less intense enemy control in the new range, but that this is due to an increased allocation to defense rather than release from specialized herbivores. This indicates that increased resistance to herbivory might be an important strategy for invasion success in systems dominated by generalist herbivores.

Animals↗