Lake County Gazette

What started as a classroom project led Lake Forest College senior Shane Hathaway to conduct research that contributed new insights into invasive ant populations in California.

In 2023, Hathaway traveled to southern California under the supervision of Professor of Biology Sean Menke. He revisited locations first studied in 1998 by a graduate student, including Torrey Pines State Reserve and the Point Loma Ecological Conservation Area. The earlier study had documented the spread of Argentine ants (Linepithema humile) but left questions about why these invasive ants succeeded in some areas and not others.

Hathaway's fieldwork found that one region experienced a decrease in the Argentine ant’s range while another showed no change, suggesting that environmental factors were limiting further expansion. He identified soil moisture as a key factor influencing where these ants could thrive.

According to the release, “Hathaway’s work helped fill in the blanks left by Professor Menke’s earlier PhD research, which had shown that irrigation fuels Argentine ant expansion but had yet to explain the patchiness of their success. By tying the ants’ two-decade retreat to soil type (and thus water retention), Hathaway’s work has added a crucial piece to the broader puzzle of invasive species ecology.”

Professor Menke now plans to expand on this research by studying how changes in urban landscaping, such as replacing lawns with artificial turf, may affect Argentine ant populations as water becomes more scarce in the region.