Floral mimesis in Thelymitra nuda (Orchidaceae)

摘要: Insect pollination occurred inThelymitra nuda R. Br. on sunny days when the ambient temperature exceeded 20 °C. The flower buds a raceme opened subsynchronously displaying brightly-colored, actinomorphic perianth and exposed contrastingly-colored, scented ornamented column. InT. staminodes filament of fertile stamen are fused to one another producing an inflated hood over anther. This staminodal is terminated in two non-ornamental, but central lobes terete lateral bearing approximately 400 white trichomes. Each trichome bears double chain 30–40 spherical, rugulose cells. Female bees, genusLasioglossum (Halictidae), were observed land directly curled their bodies around four lobed tip complex. bees attempted forage as if they collecting pollen from fertile, poricidal stamens. These applied thoracic vibration yellowish actively scraped clusters (Pseudopollen) with forelegs. Bees carried pollinaria ofT. dorsally abdomens. Abdominal contact rostellum appeared occur female bee disengaged herself hood. Observations made co-blooming flowers, analyses loads collected by suggested that orchid mimics guild blue-purple flowers lack floral nectar offer anthers. models co-bloomingLiliaceae generaDichopogon andThysanotus. However, nectarless, buzz-pollinated also extensively distributed orchid’s range. More than 30% theT. population had removed, suggesting high capacity for cross-pollination genus usually considered be self-pollinated via mechanical autogamy. study confirmed previous predictions column modifications represented trend towards pseudanthery.