IMPORTANCE Black and Hispanic populations have higher rates of coronavirus disease 2019 hospitalization and mortality than White populations but lower in-hospital case-fatality rates. The extent to which neighborhood characteristics and comorbidity explain these disparities is unclear. Outcomes in Asian American populations have not been explored. OBJECTIVETo compare COVID-19 outcomes based on race and ethnicity and assess the association of any disparities with comorbidity and neighborhood characteristics. DESIGN, SETTING, AND PARTICIPANTSThis retrospective cohort study was conducted within the New York University Langone Health system, which includes over 260 outpatient practices and 4 acute care hospitals. All patients within the system's integrated health record who were tested for severe acute respiratory syndrome coronavirus 2 between March 1, 2020, and April 8, 2020, were identified and followed up through May 13, 2020. Data were analyzed in June 2020. Among 11 547 patients tested, outcomes were compared by race and ethnicity and examined against differences by age, sex, body mass index, comorbidity, insurance type, and neighborhood socioeconomic status.EXPOSURES Race and ethnicity categorized using self-reported electronic health record data (ie, non-Hispanic White, non-Hispanic Black, Hispanic, Asian, and multiracial/other patients). MAIN OUTCOMES AND MEASURESThe likelihood of receiving a positive test, hospitalization, and critical illness (defined as a composite of care in the intensive care unit, use of mechanical ventilation, discharge to hospice, or death). RESULTSAmong 9722 patients (mean [SD] age, 50.7 [17.5] years; 58.8% women), 4843 (49.8%) were positive for COVID-19; 2623 (54.2%) of those were admitted for hospitalization (1047 [39.9%] White, 375 [14.3%] Black, 715 [27.3%] Hispanic, 180 [6.9%] Asian, 207 [7.9%] multiracial/other). In fully adjusted models, Black patients (odds ratio [OR], 1.3; 95% CI, 1.2-1.6) and Hispanic patients (OR, 1.5; 95% CI, 1.3-1.7) were more likely than White patients to test positive. Among those who tested positive, odds of hospitalization were similar among White, Hispanic, and Black patients, but higher among Asian (OR, 1.6, 95% CI, 1.1-2.3) and multiracial patients (OR, 1.4; 95% CI, 1.0-1.9) compared with White patients. Among those hospitalized, Black patients were less likely than White patients to have severe illness (OR, 0.6; 95% CI, 0.4-0.8) and to die or be discharged to hospice (hazard ratio, 0.7; 95% CI, 0.6-0.9). CONCLUSIONS AND RELEVANCEIn this cohort study of patients in a large health system in New York City, Black and Hispanic patients were more likely, and Asian patients less likely, than White patients to test positive; once hospitalized, Black patients were less likely than White patients to have (continued) Key Points Question Do outcomes among patients with coronavirus disease 2019 (COVID-19) differ by race/ethnicity, and are observed disparities associated with comorbidity and neighborhood characteristics? Findings This cohort study including ...

We have previously reported a correlation between the life-history patterns of guppies and the types of predators with which they coexist. Guppies from localities with an abundance of large predators (high predation localities) mature at an earlier age and devote more resources to reproduction than those found in localities with only a single, small species of predator (low predation localities). We also found that when guppies were introduced from a high to low predation locality, the guppy life history evolved to resemble what was normally found in this low predation locality. The presumed mechanism of natural selection is differences among localities in age/size-specific mortality (the age/size-specific mortality hypothesis); in high predation localities we assumed that guppies experienced high adult mortality rates while in the low predation localities we assumed that guppies experienced high juvenile mortality rates. These assumptions were based on stomach content analyses of wild-caught predators and on laboratory experiments. Here, we evaluate these assumptions by directly estimating the mortality rates of guppies in natural populations. We found that guppies from high predation localities experience significantly higher mortality rates than their counterparts from low predation localities, but that these higher mortality rates are uniformly distributed across all size classes, rather than being concentrated in the larger size classes. This result appears to contradict the predictions of the age/size-specific predation hypothesis. However, we argue, using additional data on growth rates and the probabilities of survival to maturity in each type of locality, that the age-specific mortality hypothesis remains plausible. This is because the probability of survival to first reproduction is very similar in each type of locality, but the guppies from high predation localities have a much lower probability of survival per unit time after maturity. We also argue for the plausibility of two other mechanisms of natural selection. These results thus reveal mortality patterns that provide a potential cause of natural selection, but expand, rather than narrow, the number of possible mechanisms responsible for life-history evolution in guppies.

Prior research has demonstrated a strong association between the species of predators that co-occur with guppies and the evolution of guppy life histories. The evolution of these differences in life histories has been attributed to the higher mortality rates experienced by guppies in high-predation environments. Here, we evaluate whether there might be indirect effects of predation on the evolution of life-history patterns and whether there are environmental differences that are correlated with predation. To do so, we quantified features of the physical and chemical environment and the population biology of guppies from seven high- and low-predation localities. We found that high-predation environments tend to be larger streams with higher light levels and higher primary productivity, which should enhance food availability for guppies. We also found that guppy populations from high-predation environments have many more small individuals and fewer large individuals than those from low-predation environments, which is caused by their higher birth rates and death rates. Because of these differences in size distribution, guppies from high-predation environments have only one-fourth of the biomass per unit area, which should also enhance food availability for guppies in these localities. Guppies from high-predation sites allocate more resources to reproduction, grow faster, and attain larger asymptotic sizes, all of which are consistent with higher levels of resource availability. We conclude that guppies from high-predation environments experience higher levels of resource availability in part because of correlated differences in the environment (light levels, primary productivity) and in part as an indirect consequence of predation (death rates and biomass density). These differences in resource availability can, in turn, augment the effect of predator-induced mortality as factors that shape the evolution of guppy life-history patterns. We found no differences in the invertebrate communities from high- and low-predation localities, so we conclude that there do not appear to be multitrophic, indirect effects associated with these differences in predation.

Transmissible pathogens are the bane of social animals, so they have evolved behaviours to decrease the probability of infection. There is no record, however, of social animals avoiding diseased individuals of their own species in the wild. Here we show how healthy, normally gregarious Caribbean spiny lobsters (Panulirus argus) avoid conspecifics that are infected with a lethal virus. Early detection and avoidance of infected, though not yet infectious, individuals by healthy lobsters confers a selective advantage and highlights the importance of host behaviour in disease transmission among natural populations.

Abstract.-We have previously reported a correlation between the life-history patterns of guppies and the types of predators with which they coexist. Guppies from localities with an abundance of large predators (high predation localities) mature at an earlier age and devote more resources to reproduction than those found in localities with only a single, small species of predator (low predation localities). We also found that when guppies were introduced from a high to low predation locality, the guppy life history evolved to resemble what was normally found in this low predation locality. The presumed mechanism of natural selection is differences among localities in age/size-specific mortality (the age/size-specific mortality hypothesis); in high predation localities we assumed that guppies experienced high adult mortality rates while in the low predation localities we assumed that guppies experienced high juvenile mortality rates. These assumptions were based on stomach content analyses of wild-caught predators and on laboratory experiments. Here, we evaluate these assumptions by directly estimating the mortality rates of guppies in natural populations. We found that guppies from high predation localities experience significantly higher mortality rates than their counterparts from low predation localities, but that these higher mortality rates are uniformly distributed across all size classes, rather than being concentrated in the larger size classes. This result appears to contradict the predictions of the age/size-specific predation hypothesis. However, we argue, using additional data on growth rates and the probabilities of survival to maturity in each type of locality, that the age-specific mortality hypothesis remains plausible. This is because the probability of survival to first reproduction is very similar in each type of locality, but the guppies from high predation localities have a much lower probability of survival per unit time after maturity. We also argue for the plausibility of two other mechanisms of natural selection. These results thus reveal mortality patterns that provide a potential cause of natural selection, but expand, rather than narrow, the number of possible mechanisms responsible for life-history evolution in guppies.Key words.-Adaptation, life-history evolution, mark-recapture, mortality, selection, size-selective predation.Received September 26, 1995. Accepted September 26, 1995 Testing evolutionary theories in natural populations requires identifying the agent of selection, evaluating how the agent operates, then manipulating it and observing the resulting dynamics of evolutionary change (Endler 1986). Satisfying these criteria is rarely possible, so inferences are more often made less directly, such as with the combination of comparative studies and genetics that comprise the discipline of ecological genetics (e.g., Ford 1971). In initial studies (Reznick 1982;Reznick and Endler 1982), we found an association between predator fauna and the life-history attributes of their prey. ...