Argentine Ants were introduced ( technically called Human Mediated Dispersal see for example here ) into Europe from their native distribution in South America and have formed a single supercolony stretching an amazing 6000km along the Mediterranean Coast. There are also other supercolonies in California and Japan.

These ants generally inhabitat urban areas  and prefer warm, moist conditions. In tropical and temperate climates they are regarded as a serious pest both in terms of impact on native biodiversity but also economic costs associated with being a pest of houses and agriculture.

This little ant has clearly taken full advantage of us humans. It has hitched a ride using human trade routes to make its way around the world. Once in a new location it gradually expands, and for reasons still not entirely clear, colonies coalesce and expand rather than defending small territories.

It’s in the top 100 invasive species in the world list.

Like the diminutive Argentine ant, Humans Homo sapiens have spread around the world – though we are able to cope with a wider range of environments than the ant – we can colonise very cold, very warm, very dry and very wet climates – with our extraordinary ability to adapt ourselves and adapt our environments to cope with pretty much all conditions.

We are also able to live together relatively peacably in supercolonies (think of the Megacities springing up across the world) like the Argentine ant, at least for the most part.

Unlike the Argentine ant we weren’t introduced by any agent other than ourselves. I suppose on that basis the spread of humans across the planet could be another example of Human Mediated Dispersal (HMD) but it’s stretching a point.

Are we an exotic (ie non-native) invasive species? I would argue that we have spread “naturally” rather than been introduced, so we can’t be treated as exotic or non-native. Has our spread affected other species, mostly to their detriment? Certainly it has so perhaps we do need to think of ourselves as an invasive species.

We look at the spread of the Argentine ant and see all the problems it causes – we kill it if its in our homes or in our crops, and wring our hands at the other species it affects (or take remedial action.)

Now consider an advanced alien civilisation – living in a patch of the galaxy nearby – they have spread out into many star systems, have resolved the challenges of interstellar travel and can see very clearly into the Earth’s atmosphere. What would they make of what they saw?

Would they consider us to be equivalent of the Argentine Ant in Europe – an invasive species that threatens to break out from a current lone colony to create a supercolony spreading through the Solar System then eventually out into the galaxy.

Or would they see us a a very successful native species doing well in its native range, with no danger of us becoming an exotic invasive?