Ants of Assateague Island: Species of Forest and Dune, and What They Eat

Ants play many roles in the food web: they spread seeds, break down dead organisms and are eaten by predators. They are eusocial, living in colonies in which a single female produces all the offspring.

About 1,000 ant species are recorded in North America, and only 124 of them have been found in Maryland. Warming could change ant communities: in the southeastern United States, rising temperatures are predicted to reduce ant diversity, while in the north diversity may rise as species expand their ranges. Little was known about the ants of Assateague Island, so in 2019 researchers from Salisbury University studied their diversity and diets.

Which ants live where

In the first part of the study, pitfall traps collected ants in the island's maritime forest and dunes.

The forest is richer in species. The dunes are a harsh place — strong sun and constantly shifting sand — and only hardy species adapted to those conditions live there.

What they eat

In the second part, the researchers collected ants, using aspirators, along with possible foods from the forest and dunes, and measured their nitrogen and carbon with stable isotope analysis. Dune ants were significantly more enriched in carbon than forest ants. Because marine foods are often richer in carbon-13, this suggests that ants in the dunes, close to the Atlantic, may eat some marine food when it is available.

New to the park's list

The study added 9 species to the park's species list, bringing the known ants of Assateague Island National Seashore to 38 — a number likely to change as future inventories find more.

Sources

• National Park Service, Assateague Island National Seashore, "Research Spotlight: Ants on Assateague." https://www.nps.gov/articles/000/research-spotlight-ants-on-assateague.htm
• The photographs, credited to Salisbury University, are not reproduced.
• Rewritten in hubnx's own words.