May 24, 2013 (Talk of the Nation) — In parts of the southeastern US, aggressive fire ants have been driven out by an even more recent arrival, the tawny crazy ant. Edward LeBrun, a researcher at the University of Texas at Austin, describes the newcomers and how one invasive species can out-invade another.

May 24, 2013 (Talk of the Nation) — Last year scientists reported that a skin cancer drug appeared to reverse the effects of an Alzheimer's-like disease in mice. But four studies out this week in Science question the original results. Ronald Petersen, director of the Mayo Clinic's Alzheimer's Disease Research Center, talks about the new findings, and the hunt for Alzheimer's drugs.

May 24, 2013 (Talk of the Nation) — North Carolina State University biologist Rob Dunn and colleagues surveyed people's pillow cases, refrigerators, toilet seats, TV screens and other household spots, to learn about the microbes that dwell in our homes. Among the findings, reported in the journal PLoS One, homes with dogs had more diverse bacterial communities, and higher numbers of "dog-associated" bacteria.

May 24, 2013 (Talk of the Nation) — A series of tornadoes struck the central United States this week, including a powerful storm in Oklahoma that killed at least 24 people. Marshall Shepherd, the president of the American Meteorological Society, describes the ingredients of major tornadoes, and how they are predicted.

May 24, 2013 (Talk of the Nation) — Smartphones, tablets and computers could help seniors stay connected to their communities and families. But a hefty price tag, steep learning curves, and designs meant for younger eyes and hands could keep some older adults from logging on. Guests discuss the best ways for seniors to tackle new technology, and how devices can be adapted to accommodate older users.