Reacción a "Reactions: the fire ant, one of the most invasive species, is already in Europe and may arrive in Spain"

From my point of view, the work is of high quality. It is based on clear evidence of the establishment of S. invicta in one where direct sampling has been carried out, which ensures the reliability of the samples. These data are supported by genetic studies, which fit perfectly with the distribution history of this species. In addition, the genetic results show that this is a polygynous population (one nest with several queens), which is the most common structure found in areas invaded by this species.  

They use genetics to check the type of nest they have found. The main point here is that if you have more queens per nest, you also have higher brood production and faster colony development. Having one queen is not the same as having several queens laying eggs at the same time. Therefore, the fact that Italian nests are polygynous means that they have the potential to make the colony grow and spread faster, even if they don't make long-distance flights very often.

On the other hand, I do not think that this species is likely to colonise the whole area shown in the article's prediction. There are a number of factors that also determine the success of the species when it arrives in a new area, such as interspecific competition for resources. And to this I would add that it is a species that is mostly distributed in warm areas, corresponding to the temperatures of its area of origin. This same tendency is found in other exotic and/or invasive species also originating from warm areas, such as the Argentine ant, the two species known as crazy ants (Paratechyna longicornis or Nylanderia jaegerskioeldi), the yellow crazy ant (Anoplolepis gracilipes)... all of them distributed mainly in the Mediterranean area. Northern distribution (Belgium, Germany, the Netherlands...) is less likely. Of course, one has to think that the scenario will change with global warming (in Poland it is becoming more noticeable) and the situation described in the article becomes a bit more realistic.  

What is carried out is a forecast (based on temperature forecasts and the characteristics of the areas) of the areas likely to be invaded, but it is important to stress that this does not indicate that they will be invaded. The results should be interpreted with caution and with a clear understanding that this is a possibility. As indicated above, there are several factors that will determine whether or not the species becomes established. It is still a prediction based on the suitability of the area, but it does not take into account the biological factors that slow down the expansion of the species: interspecific competition, scarcity of resources, infestations by parasites (fungi, bacteria...). Here the conservation of native species and their habitat plays a very important role. In well-conserved ecosystems with high native biodiversity values, invasive species are less successful in colonisation, as they face more competitors.

Spain would be one of the most affected countries, as is the case with other alien/invasive species. There is a perfect climate and a great variety of habitats (although these ants mostly like areas modified by humans, such as urban and agricultural areas). Already in 2007, it was reported that someone had arrived in Malaga with symptoms of a S. invicta sting. The most important (and dangerous) thing is that I am aware that anthills of this species are being sold in some ant shops among groups of hobbyists. That is the reason why I proposed to create a group to update the list of invasive species in Spain, and one of the proposals was S. invicta. And well, here is the proof that, if they escape from the wonderful anthill we have at home (because they will escape), it is a big risk. I have to say, though, that amateurs are becoming more and more aware of the danger of having alien species, and that is one of the most important steps to curb these problems.

Control of the invasion depends on the state in which it is found. The problem is that by the time it is discovered, the population is already highly developed. Rarely do we notice a single mini-ant in a whole country, but instead we discover many anthills when they start to become a nuisance, as happened in this article. If the population is not yet widespread, it can still be combated by various measures such as removing nests, using pesticides, etc. Lately there has been talk about the possibility of using viruses that are lethal to ants, but of course the consequences are not yet known. This is a fairly new issue. If the population is already widespread, it becomes quite difficult. We have the example of the Argentine ant, Lasius neglectus and S. invicta itself, which have not yet been eradicated in most of the invaded areas.  

As indicated in the article, citizen participation is a fundamental ally in the early detection of the problem, which facilitates eradication. And here I would add the importance of raising awareness among hobbyists, as sale is another way for exotic species to arrive. We have around 300 species on the peninsula, all wonderful, all interesting, all unique... you can't love myrmecology if you don't know how to appreciate the diversity you have in front of you.