Giant Ichneumon Wasps (Rhyssa persuasoria) of both sexes wander over the surface of logs and tree trunks, tapping with their antennae. Females are looking for wood boring larvae of the horntail wasps upon which they will lay eggs. They drill into the wood using their long ovipositor.
Males in turn are listening for newly emerging females with which to mate.
The Low Beskid - Fallen tree on the slopes of Mount Kopiec -
August 26, 2007.