A new colony structure of the invasive Argentine ant (Linepithema humile) in Southern Europe

Abstract

The Argentine ant (Linepithema humile, Mayr) is a highly invasive species that has successfully spread from its native range in South America across many zones of the globe. In Southern Europe, two continental supercolonies have been identified, the Catalonian supercolony and the main European supercolony spreading over 6,000 km. In Corsica, a French Mediterranean island, the Argentine ant has been present for 60 years. Here we compare patterns of intraspecific aggression and cuticular hydrocarbon profiles of Argentine ants in Corsica to three mainland European colonies. Chemical analyses reveal the existence of cuticular signature variations among the six study sites relative to a gradient of aggression. We find two distinct colony groups not belonging to the Catalonian supercolony, suggesting that the new population originates either (1) from an independent introduction event from the native range resulting in a third European supercolony, or (2), given the chemical proximity and the moderate level of aggression between the two groups, from an existing European population followed by a drift producing a division within the main European supercolony.

Societies Drifting Apart? Behavioural, Genetic and Chemical Differentiation between Supercolonies in the Yellow Crazy Ant Anoplolepis gracilipes

“…If both fragments come into secondary contact again, genetic and chemical differentiation may have advanced enough to result in mutual aggression and lack of gene flow. This pattern was very recently described for Linepithema humile supercolonies from Corsica and the European mainland, where the introduction of one or several L. humile propagules from the mainland to Corsica likely entailed an interruption of gene flow between Corsican and European supercolonies, resulting in the pronounced chemical and behavioural differentiation observable today [52]. This scenario may also explain parts of our data, as supercolonies P3 and P4 are likely to be established fragments of the same supercolony which have already accumulated supercolony-specific alleles and cuticular compounds despite still tolerating each other (Tables S3 and S5).…”

Recent behavioural and population genetic divergence of an invasive ant in a novel environment

“…In most tests, we found higher genetic differ-entiation between distant sites and higher aggression scores between sites than within sites. A single apparent exception to this homogeneity is that of the Corsican colony of L. humile, which does appear to have differentiated from the main European colony (Blight et al, 2010). Similarly, workers of the big headed ant Pheidole megacephala display little genetic or behavioural differentiation and an absence of isolation by distance across much of the Australian continent (Fournier et al, 2009).…”

“…Unicolonial ant species form supercolonies that exhibit behavioural and genetic differentiation between supercolonies, but no genetic or behavioural differentiation (i.e. The genetic relationships between the two colonies have not been investigated, however (Blight et al, 2010). At the most extreme, individual supercolonies of the Argentine ant (Linepithema humile) that span different continents are entirely behaviourally, genetically and chemically undifferentiated, despite over 100 years of separation (van Wilgenburg et al, 2010).…”

Agresi intraspesifik dan waktu penemuan makanan pada semut invasif Anoplolepis gracilipes di Kebun Raya Bogor

“…Blight et al (2010) melaporkan adanya koloni baru yang terbentuk pada Linepithema humile (Mayr) di Corsica yang ditandai dari adanya variasi pada susunan kimia kutikula dan perilaku semut pada uji agresi. Selain itu, Jaquiéry et al (2005) melaporkan adanya tingkat agresivitas yang selalu tinggi pada superkoloni L. humile di Eropa yang mengindikasikan terbentuknya superkoloni-superkoloni yang secara struktural berbeda satu sama lain.…”