A FUNGUS ASSOCIATED GALL MIDGE, LASIOPTERA-ARUNDINIS (SCHINER), ON PHRAGMITES-AUSTRALIS (CAV) TRIN

Lasioptera arundinis and its associated fungus attack the common reed stem. Together they proceed both stem inwards and upwards; the fungus allows the larva to penetrate in to the stem and to have access to the vascular tissues. During the last larval stage, fungus and gall midge are in the medulla attacking the innermost vascular bundles. The larva feeds on the reed stem and on the fungal symbiont. In the mature gall, when the larva stops feeding, the fungus proliferates, and a black dense mat of fungal mycelium plugs the entrance split and fills the stem medulla. The fungus protects the larva against parasites and allows an easy exit of the imago. Gall midge and fungus are perfectly adapted to each other; the gall midge imago and the first larval stage have adapted structures to carry the fungus. It appears that the gall midge has perfectly integrated the fungus in the life strategy it has evolved on the reed stem. The mutualistic relationship is much broader and goes beyond feeding relations.