POL Rodrigo Gabriel
congresos y reuniones científicas
THE UNTOLD STORY OF LINEPITHEMA HUMILE INVASION
CAROLINA PARIS; MAKI INOUE; ADRIANA RICKERT; RODRIGO POL
Simposio; XXIII Simpósio de Mirmecologia; 2017
Asociación Brasilera de Mirmecologia
In the last 37 years the invasive ant, Linepithema humile, was extensively studied outside their native area, the Parana-Uruguay river basin. However, little is known about its spread and establishment in localities close to their native area. Our aims were: 1. to update the distribution of L. humile introduced population along to Argentina; 2. to examine their population structure in relation to other worldwide introduced populations and; 3. to assess the relation between aggressive behavior among colonies and its geographic distance. DNA was extracted from 96 L. humile workers of colonies from native and introduced localities of Argentina. Then a 1700-bp partial sequence from the cytochrome c oxidase subunits I (COI) and II (COII) and cytochrome b genes were amplified. Maximum-parsimony tree was constructed including worldwide populations and L. oblongum sequences as outgroup taxa. Aggres-sive behavior was categorized at five levels. Scores above two were regarded as aggressive behav-iors. New and previously reported introduced populations were found at eight provinces of Argentina (Jujuy, Salta, La Rioja, San Juan, Mendoza, La Pampa, south of Buenos Aires and Chubut). The se-quences of amplified mtDNA revealed that the Argentinian and worldwide populations are divided into two genetically distinct clades. One haplotype included some supercolonies of Japan, the main Euro-pean (main clade), most of native Argentinian populations, and three introduced populations at vine-yards of Mendoza (Argentina). The other clade consisted of four native populations, most of introduced populations at desert areas transformed into vineyards (Mendoza, Salta), orchads (La Rioja) or urban areas (La Pampa, south of Buenos Aires and Chubut), and minor introduced supercolonies from To-kyo, Kobe C and Catalonia). The genetic data were inconsistent with the behavioral test, since some native colonies of the main clade developed aggressive behavior among them. The mean level of ag-gressive behavior among populations from native area was lower than that showed by introduced pop-ulations and between native and introduced populations. There was no significant linear relationship between aggressive behavior level and distance among locations of native and introduced populations. Therefore, within Argentina, those L. humile populations that belong to the main clade are widely dis-tributed along the coastal areas and facilitating its transportation to other regions of the world. In addi-tion, other haplotypes established successfully at islands and desert regions of Argentina. Our results raise the question about how often are introduced populations transported to the native area and which are the ecological consequences of these reintroductions.