Internal anatomy of the enlarged metatibia of gasteruptiid wasps (Hymenoptera: Gasteruptiidae)

Monday, November 11, 2013: 10:58 AM
Meeting Room 5 ABC (Austin Convention Center)
Salvatore S. Anzaldo , Entomology, Pennsylvania State University, State College, PA
István Mikó , Entomology, Pennsylvania State University, University Park, PA
Andrew R Deans , Department of Entomology, Pennsylvania State University, University Park, PA
The swollen tibia of some parasitic Hymenoptera have been shown to contain hypertrophied subgenual organs - subcuticular mechanoreceptors that are sensitive to substratum vibrations - which can allow an ovipositing female to pinpoint the concealed position of a potential host. In some taxa (e.g. Orussidae), antennal modifications allow for vibrational sounding via the tapping of the antenna on the substrate. These vibrations echo back to the insect and are detected by the subgenual organ. Gasteruptiid wasps are unusual in that they have large, clavate hind tibia in both sexes and no antennal modifications, suggesting a function of the subgenual organ for something other than host location. Through histological sectioning, confocal laser-scanning microscopy, and TEM the internal morphology of the hind tibia of gasteruptiid wasps and five other evaniomorphan taxa was explored. Novel spherical structures embedded within extensive fat bodies were only found in Gasteruption. A close association of the subgenual organ with a large proximal air sac and slight sexual dimorphism in the position of the subgenual organ in Gasteruption was also observed.