On cues, food, competition and development. An overview of the behavior and life history traits of Ibalia leucospoides and their implications for the bio-control of Sirex noctilio.

CORLEY J.C.

Conferencia; 2011 IUFRO Forest Protection Joint Meeting; 2011

IUFRO

It is widely known that for pine forestation in several countries, the invasive woodwasp Sirex noctilio is a major pest problem.  Consequently, much research focused into managing its populations has developed and in some fields, is still strongly on the rise. While biological control success has been attributed largely to the effects of the introduced parasitic nematode Deladenus siricidicola on wasp reproduction, the ability of several parasitoid species to suppress woodwasp populations is less clear, even though their seems to be a  standing belief on their importance on overall host mortality. Here, I present an overview of several years of research on the ecology and behavior of the cynipid wasp Ibalia leucospoides in Argentina. This parasitoid is present in all pine plantations established in Patagonia, having spread together with Sirex noctilio. Although parasitism levels have been estimated to reach a approximately 40% locally, it has been observed that these levels vary strongly both spatially and temporally and the ability of this species to limit woodwasp spread and outbreaks has been questioned. I will expand on what cues are relevant to female parasitoids during host searching and the implications this has on host patch exploitation strategies. Then, I’ll describe host foraging behavior and dispersal by Ibalia luecospoides and how these are influenced by con-specifics and adult feeding. Finally, I will present information on the development patterns of the parasitoid and how it can affect host suppression in time. These findings may contribute to both, increase our understanding of the persistence of Ibalia leucopsoides populations in the field and to improving rearing and release protocols for this parasitoid.  Together, the information threaded together through this overview, is expected to contribute to more accurately establishing our expectations on the role played by this parasitoid in regulating woodwasp populations affecting pine forestation worldwide.