Invasive Invertebrates of California's Central Coast Region

Aquatic Invertebrates

New Zealand Mudsnail (Potamopyrgus antipodarum)

New Zealand Mudsnails (NZMS)are extremely small snails, capable of collapsing entire food webs. NZMS are considered generalists and will eat the food that other benthic macroinvertebrates rely on for nutrients. They are so generalistic that they will out-compete important species that serve as food for local fish (i.e., the larvae of mayflies, stoneflies, and caddisflies), all of which have specific feeding habits. Once these prey species are out-competed, fish will attempt to feed on NZMS, but they are incapable of being digested and simply pass through the gut of the fish without harm . NZMS also reporduce asexually, and can create one million clones over the course of one summer. Unpublished research from California State University Monterey Bay (CSUMB) suggests that NZMS can move against currents of 74cm/s.

Professors and students at CSUMB have found NZMS in the Carmel River and Garland Ranch. Their movement within the Carmel River cannot be stopped because of their small size and large populations, save for strategically draining areas of the Carmel River (an unlikely event). It is possible to stop NZMS movement across rivers by cleaning gear thoroughly with all purpose cleaners (to kill the snails) and letting the gear dry for 72 hours before it goes in the water again (desiccate any snails that weren't killed). Dogs that go into any body of water in the California Central Coast should also be cleaned thoroughly and not allowed in water again for 72 hours to prevent the movement of NZMS across water bodies.

Argentine Ant (Linepithema humile)

The Argentine Ant (AA) has been introduced across the country, and has been increasingly common in the Central Coast. There is extensive literature on this species of ant because of its prevalency AA are among the smallest ants in California, which is why they are so successful at being invasive. https://cisr.ucr.edu/argentine_ant.html</ref> Few ants, including the AA create supercolonies :the interbreeding and co-operation of different nests of the same species. The supercolonies aid in the ant's ability to dominate whatever habitat they are in . AA pose no threat to humans, but they are considered an agriculture pest and a household pest. Most ants that invade homes are AA. AA are one of many ant species that have a symbiotic relationship with pest insects such as aphids, thus the two pests work in conjunction with one another. The success of the AA comes at the price of depleting the abundance of native ant species (i.e., Carpenter and Big-Headed ants).

Ants serve as prey for many invertebrate predators, including other ants, but AA are so small that they are seldom sought after for food. Few species specialize in predating on the AA, including some spiders in the Zordiidae family (Zordiidae, an ant-mimic spider) but few to none occur in California.