Open Access

Werner Gnatzy, Martin Jatho

• Im Vergleich zu der Vielzahl von Einzeluntersuchungen liegen nur für wenige Insektenarten (z.B. Manduca sexta: SHIELDS & HILDEBRANDT 1999 a, b; Drosophila: SHANBHAG et al. 1999, 2000) detaillierte Befunde zur Feinstruktur, Zahl und Topographie antennaler Sensillen vor. Die jetzt an Liris niger gewonnenen Daten bilden, zusammen mit solchen früherer Untersuchungen (GNATZY 1996, 2001; ANTON & GNATZY 1998; GNATZY & FERBER 1999) die Basis für derzeit laufende immuncytochemische und elektrophysiologische Arbeiten insbesondere am olfaktorischen System dieser solitären Grabwespenart. Dabei gilt unser Interesse dem ausgeprägten Sexualdimorphismus im antennalen Sensilleninventar, wie er im Verlauf dieser Untersuchungen nachgewiesen werden konnte.
• As in other parasitoid hymenoptera, the antennae of females of Liris niger play a key role in prey recognition. Furthermore the antennae are important for intraspecific communication. Using scanning and transmission electron microscopy both sexes of L. niger were examined. The antennae show sexual dimorphism in structure: 10 flagellomeres in females, 11 in males. Both sexes bear eight morphological types of sensilla: three types of s. trichodea, one type of s. basiconicum, placodeum, ampullaceum, coeloconicum and coelocapitulum, respectively. The number and distribution of the antennal sensilla is remarkably different in both sexes. Typical arrangement of all sensilla types is existent on flagellomeres 4 to 9 in females and 4 to 10 in males, respectively. On the dorsal surface of such a flagellomer in females, only s. basiconica, s. trichodea type 1 (mechanosensory) and s. trichodea type 2 (gustatory) are located; the remainning surface is dominated by s. placodea (olfactory). At the border between s. placodea and s. basiconica / s. trichodea type 2 a group of s. ampullacea can be found. Somewhat more ventrally on the inner sidewall of the flagellomeres, a field of s. coelocapitula is located. On the ventral surface approximately in the middle of the flagellomer (4th to 9th segment) a marked-off field of s. trichodea type 3 (olfactory) exists. The number of sensilla within this field increases from the 4th to the 9th segment (they are absent on flagellomer 1 to 3 and 10). About 3-5 s. coeloconica can be found on the ventral region of flagellomeres 2-10. The most proximal flagellomer displays only a small number of s. coeloconica. In males the dorsal surface of the flagellomeres (2 to 11) exhibits exclusively about 18.000 s. trichodea type 3 (olfactory). In this region also trichoms are absent. Subsequent to these s. trichodea type 3, s. placodea are expressed on the sidewalls of the flagellomeres together with s. ampullacea, s. coelocapitula, and s. coeloconica. The ventral surface is dominated by s. basiconica and s. trichodea type 2.