Where have all the native Ants gone???
Location: Mount Washington, Los Angeles, California
January 8, 2014
When we first moved to Mount Washington in 1995, we had not yet begun writing What’s That Bug? and we lived in a rental home several hundred feet away from our current offices. Across the street were several vacant lots (two houses were recently built on the site) and there was a sunny south-facing slope. We frequently saw large, red Harvester Ants in the street, but it has been at least fifteen years since we have seen any native ants in the neighborhood. We were reminded of this because of this posting from the Natural History Museum of Los Angeles County blog regarding the North Campus urban garden. We wondered why Lila and Leslie had to travel 1000 miles to bring back what should be native ants, so we called Julian Donahue, who despite living on Mount Washington for many decades, has never seen native Ants here. Though we do not promote extermination on What’s That Bug?, if we had the opportunity to eradicate anything in our grounds, it would be the invasive Argentine Ant, a species we have battled wherever we have lived in Los Angeles in the past 34 years. We believe the Argentine Ant is responsible for crowding out native Harvester Ants in our immediate neighborhood and quite possibly in all of urban Los Angeles. Julian also mentioned that we no longer have Horned Lizards locally because they feed on the Harvester Ants. See California Herps for photos of Horned Lizards. If you live in Los Angeles, and you have native Harvester Ants, please let us know. If you know how to control Argentine Ants, please let us know.
Ed. Note: We wrote to Lila Higgins and Richard Smart at the Natural History Museum to get their opinion on this matter. Here is what Richard wrote back.
Lila and I visited a property last July in Tujunga, and there were harvester ants on this homeowners property. It appeared to be a healthy colony, but it should be noted that this homeowner had worked really hard to turn his property in a native habitat.
I then checked out the website iNaturalist (which hosts some of our citizen science projects), and found a lot of Harvester Ants (Genus Pogonomyrmex) observations in California. Here is a link to a map of the Harvester Ant observations. You can click on the individual place markers to see the observations, and you can zoom in and pan around the map to focus in on the Greater L.A. Area.
Lila is traveling to San Diego today for work, so her response may be delayed.