Fig 1.
Localization and morphology of the sternal gland.
A ventral view and B lateral view on the abdomen of O. bicornis; C, D morphology of the IVth and Vth sternites of O. bicornis and E, F of O. cornuta; G coloured transection (SEM) through the abdomen in the region of the sternal gland (O. bicornis), gland tissue in red, setae in yellow; H sagittal semi-thin transection through the IVth sternite (O. bicornis); I detail of truncated setae; numbers indicate the sternites.
Fig 2.
Histology of sternal gland cells.
A basal section with basal lamina; B apical section with microvilli, arrows indicate ATER-system; C schematic overview; D pore canal in the cuticle, E recessed external surface over a pore canal; F inner surface of the gland cuticle, arrows indicate pore canals; G transection through the base of a setae with pore; bl = basal lamina, c = cuticle, fl = feltwork, g = Golgi apparatus, m = mitochondria, mv = microvilli, n = nucleus, pc = pore canal, rER = rough endoplasmatic reticulum, sc = setal canal, sj = septate junctions, v = vesicles.
Fig 3.
Surface of the IVth sternite and setae.
A section of the IVth sternite (Whole Mount); B – D Setae covering the gland area; E, F rupture preparation of sternite showing internal surface of gland cuticle and adhering setae; G closeup of a setal canal; H rupture preparation of a setae close to the base; A, B, E – H: O. bicornis, C, D: O. cornuta.
Fig 4.
Attractiveness of newly emerged O. cornuta males before and after application of sternal gland extracts or solvents.
Box plots indicate 5, 25, 50, 75, and 95 percentiles, outlying data points appear as diamonds, circles refer to the mean, numbers specify the number of trials; bic = O. bicornis, note that the alien extracts were tested at the end of the male emergence period with reduced SSB.
Fig 5.
Attractiveness of newly emerged O. bicornis males untreated, treated with sternal gland extracts or solvents, expressed as proportion of physical contacts per approach.
Box plots indicate 5, 25, 50, 75, and 95 percentiles, outlying data points appear as diamonds, circles refer to the mean, numbers specify the number of trials; cor = O. cornuta.
Fig 6.
Attractiveness of newly emerged O. bicornis males untreated, treated with sternal gland extracts or solvents expressed as copulation attempts per mount.
Box plots indicate 5, 25, 50, 75, and 95 percentiles, outlying data points appear as diamonds, circles refer to the mean, numbers specify the number of trials; cor = O. cornuta.