Robert E . Ricklefs

Learn More
Methods to assess immunocompetence requiring only a single sample are useful in comparative studies where practical considerations prevent holding or recapturing individuals. The assay for natural antibody-mediated complement activation and red blood cell agglutination described here, requiring approximately 100 microl of blood, is highly repeatable. The(More)
George Gaylord Simpson famously postulated that much of life's diversity originated as adaptive radiations-more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad-scale comparative datasets. Here, we use phylogenetic comparative data(More)
Evolutionary considerations predict that rate of aging should vary in direct relation to the mortality rate of presenescent young adults (extrinsic mortality rate) independently of differences in physiology, such as rate of metabolism. This prediction emerges from theory irrespective of the particular genetic mechanisms responsible for variation in aging.(More)
1. We analysed the relationships between species richness, island area, and habitat diversity for birds, bats, butter ̄ies, and reptiles and amphibians on 19 islands in the Lesser Antilles. Habitat diversity was quanti®ed by Simpson's index based on the total areas of ®ve vegetation types on each island. Island area varied over two orders of magnitude(More)
We studied the organization and temporal stability of an assemblage of malaria parasites (genera Plasmodium and Haemoproteus) and their passerine avian hosts in a forested study area in southern Missouri, USA, over four years. We detected parasite infections by polymerase chain reaction (PCR) of parasite DNA from host blood samples and identified parasite(More)