Suarez, then a postdoctoral student, and colleague Phillip S. Ward, a professor at the University of California at Davis, spent years identifying 232 different species from 58 genera and 12 subfamilies from the 394 records stored at the museum. Suarez and Ward then teamed with David A. Holway, a professor of biology at the University of California at San Diego, to analyze their discoveries.
Of the 232 species identified, the researchers were able to determine definitive data on nest-site preferences of 156 species. Using multiple-logistic regression, the scientists tested the influence of how many times in the records particular species were imported, nesting behavior and their interaction on the success or failure of successful establishment.
Slightly more than half of 156 species they identified were tree-nesting ants, and, only 14 percent of these arboreal ants (four species) became established in the U.S., probably because they werent dependent on specific kinds of trees, Suarez said.
"As a group of introduced species, invasive ants are clearly important," Holway said. "Five species of ants, for example, are included in the top 100 worst invasive organisms by the IUCN (The World Conservation Union)."
This National Science Foundation-funded study provides a rare look at data on "failed introductions for an important group of unintentionally introduced insects," he said. "To date, few studies on introduced insects, other than those intentionally introduced for biological control, have addressed the issue of failed introductions."