Heterospecific attraction to the vocalizations of birds in mass-fruiting trees

Abstract: A mixed-species aggregation refers to a group of individuals of different species attracted together by an environmental factor. Although they are traditionally considered not as structured as moving mixed-species groups, the composition and organization of aggregations can be influenced both by competition and by information flow between species. Frugivorous birds, for example, might move towards vocalizations of other species as cues to resources. If they differentially respond to a combination of other species’ vocalizations, an indication of a generalist fruiting tree, this could be a mechanism that creates nested structure in seed dispersal networks. We used both observational and experimental methods to study a community of frugivores in southwest China. Although the foraging niches of the birds highly overlapped, little interspecific aggression was found, suggesting a superabundant food resource. Birds were more attracted to playback of mass-fruiting trees, recorded when they were fruiting, than recordings made when those same trees were not fruiting. We compared attraction to the vocalizations of (a) an insectivorous species, (b, c, d) three species of frugivores, each presented separately, and (e) a combination of the frugivores in which their vocalizations were repeated sequentially. Response of heterospecific frugivores to the combination tape was significantly higher than to the insectivorous control, and tended (P = 0.068) to be higher than response to the frugivores. We suggest that this represents an indication that birds can use the diversity of vocalizations in a tree as a cue to understand the community of trees they interact with, as well as the community of birds. Significance statement: To our knowledge, although now used frequently with mixed-species bird flocks, playback has not been used to explore whether frugivorous birds could use heterospecific vocalizations to find fruit. We present the results of a simple, realistic experiment that shows that respondents approach trees in which birds, the majority of which are heterospecifics, are vocalizing. The results from a more complicated, controlled experiment suggest that birds may preferentially be attracted to a combination of frugivores’ sounds. We argue these results have relevance to the structure of seed dispersal networks, although we cannot demonstrate that specialist birds hone in on generalist trees by cuing on heterospecific vocalizations because of the rarity of specialists in our system

Ezetimibe added to statin therapy after acute coronary syndromes

BACKGROUND: Statin therapy reduces low-density lipoprotein (LDL) cholesterol levels and the risk of cardiovascular events, but whether the addition of ezetimibe, a nonstatin drug that reduces intestinal cholesterol absorption, can reduce the rate of cardiovascular events further is not known. METHODS: We conducted a double-blind, randomized trial involving 18,144 patients who had been hospitalized for an acute coronary syndrome within the preceding 10 days and had LDL cholesterol levels of 50 to 100 mg per deciliter (1.3 to 2.6 mmol per liter) if they were receiving lipid-lowering therapy or 50 to 125 mg per deciliter (1.3 to 3.2 mmol per liter) if they were not receiving lipid-lowering therapy. The combination of simvastatin (40 mg) and ezetimibe (10 mg) (simvastatin-ezetimibe) was compared with simvastatin (40 mg) and placebo (simvastatin monotherapy). The primary end point was a composite of cardiovascular death, nonfatal myocardial infarction, unstable angina requiring rehospitalization, coronary revascularization ( 6530 days after randomization), or nonfatal stroke. The median follow-up was 6 years. RESULTS: The median time-weighted average LDL cholesterol level during the study was 53.7 mg per deciliter (1.4 mmol per liter) in the simvastatin-ezetimibe group, as compared with 69.5 mg per deciliter (1.8 mmol per liter) in the simvastatin-monotherapy group (P<0.001). The Kaplan-Meier event rate for the primary end point at 7 years was 32.7% in the simvastatin-ezetimibe group, as compared with 34.7% in the simvastatin-monotherapy group (absolute risk difference, 2.0 percentage points; hazard ratio, 0.936; 95% confidence interval, 0.89 to 0.99; P = 0.016). Rates of pre-specified muscle, gallbladder, and hepatic adverse effects and cancer were similar in the two groups. CONCLUSIONS: When added to statin therapy, ezetimibe resulted in incremental lowering of LDL cholesterol levels and improved cardiovascular outcomes. Moreover, lowering LDL cholesterol to levels below previous targets provided additional benefit