VIBRATIONAL SOUNDING BY THE PUPAL PARASITOID PIMPLA (COCCYGOMIMUS) TURIONELLAE - AN ADDITIONAL SOLUTION TO THE RELIABILITY-DETECTABILITY PROBLEM

We investigated the ability of the pupal parasitoid Pimpla turionellae to find a simulated host (cigarette filters) hidden within paper cyli nders. A pronounced concentration of ovipositor insertions on the conc ealed filter demonstrated the ability of the parasitoid to locate hidd en hosts in the absence of chemical and visual cues. On the basis of l aser-Doppler vibrometer studies, we assume that the parasitoid uses se lf-produced vibrations to locate the filter within the paper cylinder Parasitoids showed this ability with cylinders made out of 17, 48, and 80 g paper. However, the total number of ovipositor insertions decrea sed with increasing paper weight. Based on these results, we propose t hat ovipositor insertion by P. turionellae might be induced by the con trast in resonance between hollow and solid sections of the substrate, rather than by the solidity of the substrate as such. We discuss this form of vibrational sounding as an additional solution to the reliabi lity-detectability problem faced by host seeking (pupal) parasitoids. (C) 1998 Academic Press.