Multilevel genetic analyses of two European supercolonies of the Argentine ant, Linepithema humile.
Details
State: Public
Version: author
Serval ID
serval:BIB_30EDF257C57B
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Multilevel genetic analyses of two European supercolonies of the Argentine ant, Linepithema humile.
Journal
Molecular Ecology
ISSN
0962-1083
Publication state
Published
Issued date
02/2005
Peer-reviewed
Oui
Volume
14
Number
2
Pages
589-598
Language
english
Abstract
Some ants have an extraordinary unicolonial social organization, whereby individuals mix freely among physically separated nests. Recently, it was shown that the European population of Linepithema humile consisted of two enormous unicolonial supercolonies. Workers of the same supercolony are never aggressive to each other. In contrast, aggressiveness is invariably high between workers from different supercolonies. Here we investigated whether gene flow occurs between two supercolonies. We identified a contact zone in which we sampled 46 nests. For each nest, aggression tests were conducted against workers from reference nests from both supercolonies. Workers were always very aggressive towards workers of one of the supercolonies but not to workers of the other. Thus, all nests could be clearly assigned to one of the two supercolonies. For 22 of the 46 nests, we genotyped 15-16 workers at five microsatellite loci. A four-level hierarchical analysis of variance revealed very strong genetic differentiation between the two supercolonies (F(SUPERCOLONY-TOTAL) = 0.541) and low differentiation between sectors (i.e. group of nests connected together with trails) within supercolonies (F(SECTOR-SUPERCOLONY) = 0.064). The very high differentiation between the two supercolonies indicates a lack of ongoing gene flow, a conclusion further bolstered by the finding that the two supercolonies share no common alleles at two of the five microsatellite loci. A Bayesian clustering method also revealed the occurrence of two distinct clusters. These clusters exactly match the grouping obtained by aggression tests. None of the 332 genotyped individuals were admixed despite the fact that some nests of the two supercolonies were separated by less than 30 m. These results demonstrate that the two supercolonies have completely separate gene pools.
Keywords
Aggression/physiology, Analysis of Variance, Animals, Ants/genetics, Ants/physiology, Gene Frequency, Genetic Variation, Genetics, Population, Genotype, Linkage Disequilibrium, Microsatellite Repeats/genetics, Spain, Species Specificity
Pubmed
Web of science
Create date
24/01/2008 19:39
Last modification date
20/08/2019 14:15