Location: Tammsalen, Ecology Centre
Tamm Seminar by Blas Lavandero, Instituto de Ciencias Biologicas, Universidad de Talca, Chile.
Blas Lavandero will talk about the English Grain Aphid (Sitobion avenae) taht was introduced from Europe in the 1970s to Chilean agroecosystems. It was an important pest of cereal crops triggering the introduction of several Aphidiinae aphid parasitoids from 1976-1979.
However, changes in landscape complexity and agricultural intensification could have affected the role of these introduced organisms over time. Moreover, the interactions of these different introduced species in Chile were never studied. On the other hand the microbial community inhabiting insects can be as diverse as the symbiotic associations that they maintain with their host insects.
Ancient mutualistic relationships with obligate bacterial endosymbionts that provide essential nutrients and secondary endosymbionts that may produce important phenotypic effects on their hosts are common among plant sap-sucking insects. Secondary endosymbionts have been found to affect directly the effect of parasitoids on aphids. Despite obvious protective benefits, not all individuals of one species harbor facultative endosymbionts, being commonly found in intermediate frequencies within the host natural populations.
In a series of studies we have explored the population dynamics in the field of the main aphid species, the frequency of known or unknown secondary endosymbionts in these populations and their parasitism levels observed on cereal crops in contrasting landscape contexts. The putative role of the main secondary endosymbiont found in the field, was examined in relation to one of the most common parasitoids species in laboratory and field studies. The potential interactions between these symbionts were also explored for different clones of Sitobion avenae that dominate the Chilean landscape.