The Evolution of the Demand for Temporary Help Supply Employment in the United States

The Bureau of Labor Statistics has reported an extraordinary increase in temporary help supply (THS) employment during the late 1980s and the 1990s. However, little is known about the venues where these THS employees actually work. Our estimates indicate that the proportion of THS employees in each major American industry, except the public sector, increased during 1977-97. By 1997, close to 4 percent of the employees in manufacturing and services were THS workers. In the service sector, the increase was accompanied by a large increase in direct hires. In manufacturing, however, it was accompanied by a decline in direct hiring from its peak in 1989 even though output increased substantially in the 1990s. Practically, all of the growth in THS employment is attributed to a change in the hiring behavior of firms, rather than to a disproportional increase in the size of more THS-intensive industries.

A novel bee host cannot detect a microbial parasite, in contrast to its original host

Organisms that can detect parasites may have a greater likelihood of avoiding exposure to them. We would expect hosts that share an evolutionary history with a parasite to be more likely to detect and avoid it compared to novel hosts. Nosema ceranae is a gut parasite of the Asian honey bee, Apis cerana, that has relatively recently been detected in the western honey bee, Apis mellifera. Using a Proboscis Extension Response assay, we found that A. cerana was significantly more likely than A. mellifera to avoid sucrose solutions with concentrations above 1 x 10(6) N. ceranae spores per mL. However, neither species avoided the sucrose solutions with lower N. ceranae concentrations, similar to those detected on flowers

Epiphytic ant-plant obtains nitrogen from both native and invasive ant inhabitants

Ant-plants have been extensively used as model systems in the study of the evolution and ecology of mutualisms. Using a 15N isotope labeling experiment, we found that both a native ant mutualist (Philidris cordata) and an invasive ant (Pheidole megacephala) provide nitrogen to the Australian ant-plant Myrmecodia beccarii

Epiphytic ant-plant obtains nitrogen from both native and invasive ant inhabitants

Ant-plants have been extensively used as model systems in the study of the evolution and ecology of mutualisms. Using a 15N isotope labeling experiment, we found that both a native ant mutualist (Philidris cordata) and an invasive ant (Pheidole megacephala) provide nitrogen to the Australian ant-plant Myrmecodia beccarii

Epiphytic ant-plant obtains nitrogen from both native and invasive ant inhabitants

Ant-plants have been extensively used as model systems in the study of the evolution and ecology of mutualisms. Using a 15N isotope labeling experiment, we found that both a native ant mutualist (Philidris cordata) and an invasive ant (Pheidole megacephala) provide nitrogen to the Australian ant-plant Myrmecodia beccarii