Pollination ecology of Tetratheca juncea (Tremandraceae) : finding the pollinators

Tetratheca juncea Smith (family Tremandraceae) is a terrestrial herbaceous plant now mainly found in the Lake Macquarie area of coastal NSW and listed as Vulnerable under Schedule 2 of the NSW Threatened Species Conservation Act 1995. This study carried out from July 2001 to June 2002 records the observation and identification of two species of native bee buzz-pollinating its flowers and describes a direct relationship between the first appearance of a pollinator and the commencement of seed set. Findings from this study with respect to the pollination ecology of Tetratheca juncea are: • There is a strong flowering period from September to January, though a number of flowers can be found on some plants across the geographic range of the plant in all months of the year; • Two species of native bee Lasioglossum convexum and Exoneura sp, were confirmed collecting pollen from the flowers by way of buzz pollination; • Fruiting only occurred in coincidence with flower pollination by these bees; • Flowering, seed set and seed release was a concurrent process while ever the bees were active; • The bees are polylectic and the sexual reproductive process in Tetratheca juncea appears to be pollinator-limited