Life Sciences Commons^™

Two-Decade-Long Trends (1975-1997) In The Incidence, Hospitalization, And Long-Term Death Rates Associated With Complete Heart Block Complicating Acute Myocardial Infarction: A Community-Wide Perspective, Frederick Spencer, Samer Jabbour, Darleen Lessard, Jorge Yarzebski, Shmuel Ravid, Virginia Zaleskas, Michael Hyder, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: The purpose of this community-wide study was to describe a >2-decade-long experience (1975-97) in the incidence and death rates associated with complete heart block (CHB) in patients with acute myocardial infarction (AMI). Limited population-based data exist describing recent, and changes with time therein, incidence and case-fatality rates associated with CHB complicating AMI.

METHODS: We conducted an observational study of 9082 metropolitan Worcester, Mass, residents (1990 census = 437,000) hospitalized with validated AMI in all greater Worcester hospitals during 11 1-year periods between 1975 and 1997.

RESULTS: Overall, CHB developed in 5.0% of patients with AMI. The incidence rates of …

Use Of The Invasive Management Strategy For Patients With Non-Q-Wave Myocardial Infarction: An Observational Database Report From The Worcester Heart Attack Study, Harold Dauerman, Jorge Yarzebski, Joel Gore, Darleen Lessard, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Recent randomized clinical trials have suggested a benefit of an invasive management strategy in patients with acute coronary syndromes. However, the broader use and impact of the invasive management approach has not been established for patients with acute coronary syndromes beyond the relatively narrow patient populations studied in randomized, clinical trials. METHODS: Residents of the Worcester, Mass, area who were hospitalized with non-Q-wave acute myocardial infarction (AMI) at all area hospitals in 5 annual periods between 1990 and 1997 comprised the sample of interest (n = 2436). We examined the extent of use of an invasive versus a conservative …

A 30-Year Perspective (1975-2005) Into The Changing Landscape Of Patients Hospitalized With Initial Acute Myocardial Infarction: Worcester Heart Attack Study, Kevin Floyd, Jorge Yarzebski, Frederick Spencer, Darleen Lessard, James Dalen, Joseph Alpert, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: The effects of lifestyle changes and evolving treatment practices on coronary disease incidence rates, demographic and clinical profile, and the short-term outcomes of patients hospitalized with acute myocardial infarction have not been well characterized. The purpose of this study was to examine multidecade-long trends (1975-2005) in the incidence rates, demographic and clinical characteristics, treatment practices, and hospital outcomes of patients hospitalized with an initial acute myocardial infarction from a population-based perspective. METHODS AND RESULTS: Residents of the Worcester, Mass, metropolitan area (median age, 37 years; 89% white) hospitalized with an initial acute myocardial infarction (n=8898) at all greater-Worcester medical …

Trends In Atrial Fibrillation Complicating Acute Myocardial Infarction, Jane Saczynski, David Mcmanus, Zheng Zhou, Frederick Spencer, Jorge Yarzebski, Darleen Lessard, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI) and this arrhythmia is associated with increased morbidity and mortality in patients with AMI. Limited information is available, however, about changing, and contemporary, trends in the incidence and death rates associated with AF complicating AMI. We examined the magnitude and impact of AF and the risk of stroke and hospital and long-term death rates in a population-based study of patients hospitalized with AMI. The study population consisted of 7,513 residents of the Worcester, Massachusetts, metropolitan area hospitalized with AMI at all greater Worcester medical centers during 9 biennial …

Contemporary Trends In Evidence-Based Treatment For Acute Myocardial Infarction, Marco Fornasini, Jorge Yarzebski, David Chiriboga, Darleen Lessard, Frederick Spencer, Philip Aurigemma, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Guidelines for the management of patients with acute myocardial infarction recommend the routine use of 4 effective cardiac medications: angiotensin-converting enzyme inhibitors, aspirin, beta-blockers, and lipid-lowering agents. Limited data are available, however, about the contemporary and changing use of these therapies, particularly from a population-based perspective. The study describes differences in the use of these medications during hospitalization for acute myocardial infarction according to age, gender, and period of hospitalization.

METHODS: The study population consisted of 6334 women and men treated at 11 hospitals in the Worcester, Mass, metropolitan area for acute myocardial infarction in 6 annual periods between …

Twenty Year Trends (1975-1995) In The Incidence, In-Hospital And Long-Term Death Rates Associated With Heart Failure Complicating Acute Myocardial Infarction: A Community-Wide Perspective, Frederick Spencer, Theo Meyer, Robert Goldberg, Jorge Yarzebski, Mark Hatton, Darleen Lessard, Joel Gore

Jorge L. Yarzebski

OBJECTIVES: To describe from a population-based perspective, recent and temporal (1975-1995) trends in the incidence, in-hospital and postdischarge case-fatality rates of heart failure (HF) complicating acute myocardial infarction (AMI). BACKGROUND: Extremely limited data are available describing the incidence and case-fatality rates associated with HF complicating AMI from a community-wide perspective. METHODS: The medical records of 6,798 residents of the Worcester, Massachusetts metropolitan area with validated MI and without previous HF hospitalized in 10 annual periods between 1975 and 1995 were reviewed. RESULTS: The proportion of AMI patients developing HF during hospitalization declined between 1975-1978 (38%) and 1993-1995 (33%) (p < 0.001). …

Long-Term Trends In The Use Of Coronary Reperfusion Strategies In Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Frederick Spencer, Joseph Okolo, Darleen Lessard, Jorge Yarzebski, Joel Gore

Jorge L. Yarzebski

BACKGROUND: The objectives of our study were to examine long-term (1986-2003) trends in the use of percutaneous coronary interventions (PCI) and thrombolytic therapy in the management of patients hospitalized with acute myocardial infarction (AMI) while our secondary study goal was to examine factors associated with use of these coronary reperfusion strategies. While there have been considerable changes in the management of patients hospitalized with AMI over time, limited contemporary data are available about changing trends in the use of different coronary reperfusion strategies, particularly from the more generalizable perspective of a population-based investigation. METHODS: The study sample consisted of 9,422 …

Changes Over Time In The Incidence And Case-Fatality Rates Of Primary Ventricular Fibrillation Complicating Acute Myocardial Infarction: Perspectives From The Worcester Heart Attack Study, Craig Thompson, Jorge Yarzebski, Robert Goldberg, Darleen Lessard, Joel Gore, James Dalen

Jorge L. Yarzebski

BACKGROUND: Limited population-based data are available that describe temporal and recent trends in the incidence and case-fatality rates in patients with primary ventricular fibrillation (VF) complicating acute myocardial infarction (AMI). The purpose of this study was to describe changes over a 22-year period (1975 through 1997) in the incidence and hospital case-fatality rates of primary VF complicating AMI from a multihospital, community-wide perspective. METHODS AND RESULTS: This was an observational study of metropolitan Worcester residents hospitalized with a validated uncomplicated AMI (n = 5020) in all hospitals in the Worcester, Massachusetts, metropolitan area (1990 census population = 437,000) during 11 …

Sex Differences In 2-Year Mortality After Hospital Discharge For Myocardial Infarction, Viola Vaccarino, Harlan Krumholz, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: An interaction between sex and age is thought to affect hospital mortality after myocardial infarction; younger, but not older, women have been shown to have higher mortality rates than men. It is currently unknown whether findings are similar after hospital discharge. OBJECTIVE: To determine whether an interaction between sex and age affects 2-year mortality after myocardial infarction. DESIGN: Community-based prospective cohort study. SETTING: 16 community hospitals serving the Worcester, Massachusetts, metropolitan area. PATIENTS: 6826 patients who survived hospitalization for acute myocardial infarction during ten 1-year periods between 1975 and 1995. MEASUREMENTS: Mortality 2 years after hospital discharge. RESULTS: The …

Prehospital Transport Of Patients With Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Daniel Kramer, Jorge Yarzebski, Darleen Lessard, Joel Gore

Jorge L. Yarzebski

OBJECTIVE: The objectives of this population-based study were to examine the use of emergency medical services (EMS) in greater Worcester, Massachusetts, residents (2000 census = 478,000) hospitalized with acute myocardial infarction (AMI) at all metropolitan Worcester medical centers in four biennial periods between 1997 and 2003. A secondary study aim was to describe the demographic and clinical characteristics of patients with AMI transported to metropolitan Worcester hospitals by EMS, compared with those transported by other means, and their hospital outcomes. METHODS: We reviewed the medical records of 3805 patients hospitalized for confirmed AMI at 11 greater Worcester medical centers during …

Twenty-Two Year (1975 To 1997) Trends In The Incidence, In-Hospital And Long-Term Case Fatality Rates From Initial Q-Wave And Non-Q-Wave Myocardial Infarction: A Multi-Hospital, Community-Wide Perspective, Mark Furman, Harold Dauerman, Robert Goldberg, Jorge Yarzebski, Darleen Lessard, Joel Gore

Jorge L. Yarzebski

OBJECTIVES: The goal of this study was to examine long-term trends in the incidence, in-hospital and long-term mortality patterns in patients with an initial non-Q-wave myocardial infarction (NQWMI) as compared with those with an initial Q-wave myocardial infarction (QWMI). BACKGROUND: Limited data are available describing trends in the incidence and mortality from an initial QWMI and NQWMI from a multi-hospital community-wide perspective. METHODS: Our study was an observational study of 5,832 metropolitan Worcester, Massachusetts residents (1990 census = 437,000) hospitalized with validated initial acute MI in all greater Worcester hospitals during 11 annual periods between 1975 and 1997. RESULTS: The …

Leukocytosis And Adverse Hospital Outcomes After Acute Myocardial Infarction, Vandana Menon, Darleen Lessard, Jorge Yarzebski, Mark Furman, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

An elevated white blood cell (WBC) count at the time of hospital presentation is associated with increased mortality after acute myocardial infarction (AMI). The association between WBC count and the development of clinically significant complications of AMI and death during hospitalization for AMI is, however, less clear. The objectives of this observational study were to examine the association between baseline WBC count, the development of heart failure, cardiogenic shock, and death during hospitalization for AMI from a more generalizable community-wide perspective. The study sample consisted of adult residents of all ages from the Worcester, Massachusetts, metropolitan area (1990 census estimate …

Recent And Temporal Trends (1975 To 1999) In The Treatment, Hospital, And Long-Term Outcomes Of Hispanic And Non-Hispanic White Patients Hospitalized With Acute Myocardial Infarction: A Population-Based Perspective, Jorge Yarzebski, Carmen Bujor, Darleen Lessard, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Extremely limited population-based data are available describing recent and temporal trends in the characteristics, treatment, and outcomes of Hispanic and non-Hispanic white patients hospitalized with acute myocardial infarction (AMI).

METHODS: This was a community-based, observational study of 9649 greater Worcester residents hospitalized in all hospitals serving the Worcester, Massachusetts, metropolitan area in 12 one-year periods between 1975 and 1999. In the total study sample, 171 (2%) patients were Hispanic. Hispanic patients were matched with 395 non-Hispanic white patients on the basis of age, sex, and year of hospitalization.

RESULTS: Hispanics were more likely to present to greater Worcester hospitals …

Delays In Seeking Medical Care In Hospitalized Patients With Decompensated Heart Failure, Robert Goldberg, Jordan Goldberg, Sean Pruell, Jorge Yarzebski, Darleen Lessard, Frederick Spencer, Joel Gore

Jorge L. Yarzebski

PURPOSE: The magnitude of, and factors associated with, prolonged delay in seeking medical care in patients with acute myocardial infarction has been well described. It is unknown, however, what the extent of, and factors associated with, prehospital delay are in patients hospitalized with acute heart failure. The purpose of this study was to examine patterns of prehospital delay, and factors associated with delay in seeking medical care, in patients hospitalized with acute heart failure at all 11 medical centers in the Worcester, Massachusetts metropolitan area. METHODS: The medical records of 2587 greater Worcester residents with decompensated heart failure who were …

Trends In The Use Of Echocardiography And Left Ventriculography To Assess Left Ventricular Ejection Fraction In Patients Hospitalized With Acute Myocardial Infarction, Samuel Joffe, Armen Chalian, Dennis Tighe, Gerard Aurigemma, Jorge Yarzebski, Joel Gore, Darleen Lessard, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Although current guidelines strongly recommend the measurement of ejection fraction (EF) in all patients hospitalized with acute myocardial infarction (AMI), there are limited data available describing trends in the use of diagnostic modalities to assess EF in these patients. The purpose of this study was to evaluate trends in the use of ventriculography and echocardiography to measure EF in a community sample of patients hospitalized with AMI. METHODS: The medical records of 5,380 residents of the Worcester (MA) metropolitan area hospitalized with AMI at 11 greater Worcester medical centers between 1997 and 2005 were reviewed. RESULTS: Between 1997 and …

Gender Differences In The Treatment Of Patients With Acute Myocardial Infarction. A Multihospital, Community-Based Perspective, Paul Pagley, Jorge Yarzebski, Robert Goldberg, Z. Chen, David Chiriboga, Priscilla Dalen, Jerry Gurwitz, Joseph Alpert, Joel Gore

Jorge L. Yarzebski

OBJECTIVE: As part of a community-wide study examining temporal trends in the incidence and survival rates of acute myocardial infarction, we examined differences between the sexes in overall utilization rates and changes over time, therein, of various therapies used in the management of acute myocardial infarction. DESIGN: Nonconcurrent prospective study. PATIENTS: Three thousand three hundred sixty-one men and 2119 women hospitalized with validated acute myocardial infarction in 16 hospitals in the Worcester, Mass, metropolitan area during 1975, 1978, 1981, 1984, 1986, 1988, and 1990. RESULTS: After controlling, by means of a logistic regression analysis, for a variety of patient-related factors …

A Two-Decades (1975 To 1995) Long Experience In The Incidence, In-Hospital And Long-Term Case-Fatality Rates Of Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Jorge Yarzebski, Darleen Lessard, Joel Gore

Jorge L. Yarzebski

OBJECTIVES: The purpose of the present study is to describe changes over two decades (1975 to 1995) in the incidence, in-hospital and long-term case-fatality rates associated with acute myocardial infarction (AMI) from a multihospital community-wide perspective.

BACKGROUND: Despite the magnitude of, and mortality associated with acute myocardial infarction (AMI), relatively limited population-based data are available to describe recent and temporal trends in the attack and case-fatality rates associated with AMI from a representative population-based perspective.

METHODS: The community-based study included 5,270 residents of the Worcester, Massachusetts, metropolitan area hospitalized with confirmed initial AMI in all metropolitan Worcester, Massachusetts, hospitals (1990 …

Changing Trends In The Evaluation Of Ejection Fraction In Patients Hospitalized With Acute Myocardial Infarction: The Worcester Heart Attack Study, Paul Santolucito, Dennis Tighe, Darleen Lessard, Rovshan Ismailov, Joel Gore, Jorge Yarzebski, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Extent of left ventricular dysfunction in patients with acute myocardial infarction (AMI) is an important predictor of subsequent morbidity and mortality. It is unclear, however, how often ejection fraction (EF) findings are evaluated in the setting of AMI, and the characteristics of patients who do not have their EF evaluated, particularly from the more generalizable perspective of a population-based investigation.

PURPOSE: The purpose of this study was to examine nearly 3 decade long trends (1975-2003) in the evaluation of EF in patients admitted with confirmed AMI (n = 12,760) to all greater Worcester (Massachusetts) hospitals during 14 annual periods. …

Age-Specific Differences In The Use Of Thrombolytic Therapy And Hospital Outcomes In Patients With Acute Myocardial Infarction: A Community-Wide Perspective, Omar Ali, Immad Sadiq, Robert Goldberg, Jorge Yarzebski, Darleen Lessard, Jerry Gurwitz, Joel Gore

Jorge L. Yarzebski

BACKGROUND: Relatively limited information is available about recent, and trends over time, use of thrombolytic therapy in patients of different ages hospitalized with acute myocardial infarction and the association between use of thrombolytic therapy and hospital outcomes. METHODS: We conducted an observational study of 5601 residents of the Worcester, Massachusetts, metropolitan area (1990 census = 437,000) with confirmed acute myocardial infarction in all local hospitals during 6 one-year periods between 1990 and 1999. RESULTS: Despite relatively stable use of thrombolytic therapy between 1990 and 1995, decreases in the use of thrombolytic therapy in all patients with acute myocardial infarction were …

Recent Trends In The Incidence Rates Of And Death Rates From Atrial Fibrillation Complicating Initial Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Jorge Yarzebski, Darleen Lessard, Jacqueline Wu, Joel Gore

Jorge L. Yarzebski

BACKGROUND: Limited information is available about recent trends in the incidence and death rates from atrial fibrillation (AF) complicating acute myocardial infarction (AMI). The purpose of this study was to examine the impact and trends over time of AF complicating initial AMI. METHODS: We conducted a longitudinal study of 2596 residents of the Worcester, Massachusetts, metropolitan area with initial AMI and without previous AF who were hospitalized at all area hospitals in 5 annual periods between 1990 and 1997. RESULTS: A total of 13% of hospitalized patients developed AF. There was a marked decrease in the proportion of patients who …

Use Of Do-Not-Resuscitate Orders In Patients With Kidney Disease Hospitalized With Acute Myocardial Infarction, Joline Chen, Jonathan Sosnov, Darleen Lessard, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Patients with kidney disease are at increased risk for adverse health outcomes in comparison to patients without kidney disease. Therefore, patients with kidney disease may have greater use of do-not-resuscitate (DNR) orders than patients without kidney disease in the setting of an acute illness. We examined the association between advanced kidney disease and use of DNR orders in patients admitted with an acute myocardial infarction (AMI) to all greater Worcester, MA, hospitals as part of an epidemiological study.

METHODS: Use of DNR orders in 4,033 Worcester residents hospitalized with AMI at 11 greater Worcester medical centers during 1997, 1999, …

Treatment Practices And Outcomes Of Patients With Established Peripheral Arterial Disease Hospitalized With Acute Myocardial Infarction In A Community Setting, Frederick Spencer, Darleen Lessard, Chyke Doubeni, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: There are little contemporary data available describing the hospital and long-term outcomes of patients with peripheral arterial disease (PAD) who are hospitalized with acute myocardial infarction (AMI). The objectives of our population-based study were to examine the hospital and long-term outcomes, as well as the use of different treatment practices, among patients with established PAD who were hospitalized with AMI. METHODS: The study sample consisted of 4480 patients hospitalized with AMI at all Worcester, Mass, medical centers in 4 alternate years between 1997 and 2003. RESULTS: Among the metropolitan Worcester residents hospitalized with AMI, 13.5% had a history of …

Trends (1986 To 1999) In The Incidence And Outcomes Of In-Hospital Stroke Complicating Acute Myocardial Infarction (The Worcester Heart Attack Study), Frederick Spencer, Joel Gore, Jorge Yarzebski, Darleen Lessard, Elizabeth Jackson, Robert Goldberg

Jorge L. Yarzebski

Although stroke is an infrequent hospital complication of acute myocardial infarction (AMI), limited contemporary data are available about the incidence and death rates associated with this serious complication. The objective of this population-based study was to examine temporal trends (1986 to 1999) in the risk of stroke and associated hospital outcomes in patients hospitalized with AMI. This was an observational study of 6,325 metropolitan Worcester, Massachusetts, residents hospitalized with validated AMI and without prior stroke at all greater Worcester hospitals during 8 one-year periods between 1986 and 1999. Overall, 1.5% of patients (n = 92) with confirmed AMI developed an …

Nestling Tree Swallow (Tachycineta Bicolor) Diets In An Upland Old Field In Western Michigan, Matthew Johnson, Michael Lombardo

Michael P Lombardo

We collected and identified 1852 prey items from 89 boluses delivered to 62 nestling tree swallows (Tachycineta bicolor) at 14 nests in an upland old field in western Michigan. We found that 90.8% of nestling diets was insects from the Orders Diptera, Homoptera, Hymenoptera and Coleoptera. We also found clam and snail shells in boluses. Over the most common brood sizes of 4-6 nestlings, brood size was inversely proportional to the number of items per bolus delivered to nestlings although mean dry and mean organic weight of boluses did not differ. Bolus composition was not influenced by weather …

Effect Of Feathers As Nest Insulation On Incubation Behavior And Reproductive Performance Of Tree Swallows (Tachycineta Bicolor), Michael Lombardo, Ruth Bosman, Christine Faro, Stephen Houtteman, Timothy Kluisza

Michael P Lombardo

Many species of birds line their nests with feathers, presumably because of the insulative qualities of feathers and because feathers may act as a barrier between nest parasites and nestlings. In 1993, we experimentally examined the role of feathers as nest insulation on the incubation behavior, nestling growth, and reproductive performance of Tree Swallows (Tachycineta bicolor) nesting in boxes in western Michigan. There were no significant differences between the incubation rhythms of females with experimental nests (i.e. no feathers) and females with control nests (i.e. with feathers). Nestlings that were reared in control nests had significantly longer right tarsi and …

Repeated Sampling Affects Tree Swallow Semen Characteristics, Michael Lombardo, M.L. Green, P.A. Thorpe, M.R. Czarnowski, H.W. Power

Michael P Lombardo

Male Tree Swallows (Tachycineta bicolor) face intense sperm competition because mated pairs copulate frequently, extra-pair copulations are common, and females store sperm. We examined the effects of repeated sampling on the characteristics of Tree Swallow semen by manually expressing semen from 15 males immediately after capture (T₀) and then hourly for 4 h (T₁-T₄). The semen characteristics of individual males varied in response to repeated sampling. The total number of sperm cells we obtained from each male over the 4-h sampling period varied from 10⁴-10⁷. Semen samples lacking …

Communities Of Cloacal Bacteria In Tree Swallow Families, Michael Lombardo, Patrick Thorpe, R. Cichewicz, M. Henshaw, C. Millard, C. Steen, T. Zeller

Michael P Lombardo

Our aim in this study was to survey the communities of bacteria found in the cloacae of adult and nestling Tree Swallows (Tachycineta bicolor), determine if there were familial patterns of prevalence, and determine if there were relationships between bacteria loads and nestling size when 12 days old and fledging success.

Left-Sided Directional Bias Of Cloacal Contacts During House Sparrow Copulations, Karen Nyland, Michael Lombardo, Patrick Thorpe

Michael P Lombardo

Most female birds have only a left ovary and associated oviduct. The entry to the oviduct is on the left side of the urodeum of the cloaca. This arrangement may favor males that mount females from the left during copulation if it results in sperm being placed closer to the opening of the oviduct. Therefore, we predicted a left-sided directional bias of cloacal contacts during House Sparrow (Passer domesticus) copulations. Cloacal contacts from the left outnumbered those from the right 74 to 25 (3:1) during 25 bouts of copulation at 11 House Sparrow nests. While this pattern suggests that a …

Individual, Temporal, And Seasonal Variation In Sperm Concentration In Tree Swallows, Michael Lombardo, Armetris Forman, Matthew Czarnowski, Patrick Thorpe

Michael P Lombardo

We determined sperm concentrations in Tree Swallows (Tachycineta bicolor) by manually expressing semen samples from males during prelaying, egg-laying, incubation, and nestling periods. Sperm concentrations varied by orders of magnitude (0-109 sperm mL-1) among males. Sperm concentrations were highest during the incubation period and lowest during the prelaying period. None of the samples collected during the prelaying, egg-laying, and incubation periods were devoid of sperm. In contrast, 45% of samples collected during the nestling period lacked sperm. Sperm concentrations (1) did not vary over the course of the morning during prelaying, egg-laying, and incubation periods but significantly increased during the …

Access To Mutualistic Endosymbiotic Microbes: An Underappreciated Benefit Of Group Living, Michael Lombardo

Michael P Lombardo

"The original publication is available at www.springerlink.com"

A central question in behavioral ecology has been why animals live in groups. Previous theories about the evolution of sociality focused on the potential benefits of decreased risk of predation, increased foraging or feeding efficiency, and mutual aid in defending resources and/or rearing offspring. This paper argues that access to mutualistic endosymbiotic microbes is an underappreciated benefit of group living and sets out to reinvigorate Troyer’s hypothesis that the need to obtain cellulolytic microbes from conspecifics influenced the evolution of social behavior in herbivores and to extend it to nonherbivores. This extension is …