Gambusia affinis: A Professional Invader

Photo credit: J Centavo @Flickr

I'm far away from the fishpond right now, taking a summer modeling course through Michigan State University. However, talk of some fishpond species has crossed the Pacific Ocean and reached me here. Dr. Andy Sih, a behavioral ecologist from The University of California Davis is visiting the campus and just gave a talk on "behavioral syndromes" (a technical name for personalities) and their role in mate choice, population dispersal, and invasion of new habitats. Interestingly, one of the animals his lab has used to study behavioral effects on invasion is Gambusia affinis, the western mosquitofish, which is invasive to Hawaii and very plentiful in the fishpond. According to the Global Invasive Species Database, G. affinis is one of the Top 100 Invasive Pests in the world. Due to its generalist diet, it competes with other fish for resources and often also eats the eggs of other fish (including economically desirable ones, though it's unknown whether it eats awa'awa or moi eggs). The interesting thing Dr. Sih said about G. affinis, though, is that among the members of the Gambusia genus, G. affinis is uniquely invasive and aggressive. Its feeding voracity contributes to its ability to spread, establish in new locations, and have heavy impacts on the local species once it establishes. This makes it a good study organism for behavioral syndromes that may be characteristic of invasive animal species. Dr. Sih's research suggests that behavioral syndromes such as feeding voracity may make some species (and some individuals within species) better invaders.