We are currently researching the pollination requirements/restrictions/deficiencies and other potential threats impacting on an endangered plant species, Astrotricha roddii, Rodd’s Star Hair (Fig. 1), a species that has been in decline for many years in response to droughts and over-grazing by goats. This project is a collaboration between researchers at the University of New England (Australia) and the NSW Department of Planning Infrastructure and Environment.
Figure 1. Astrotricha roddii in its natural habitat, in sclerophyllous woodland on granite in north-western New South Wales.
In November 2020 we visited the only known, vigorous population (fenced off from goats) that was in flower to begin our investigation of the plant’s pollination ecology.
We saw three species of bees at the Astrotricha roddii flowers. The most common species was Leioproctus crenulatus; one was a Megachilid species (Fig. 2), yet unidentified; and the third was a small black bee!, probably a Halictid but I saw only one and very briefly – it was eating the pollen into a crop like some Halictids do, so unlikely to be a good pollinator. Oh, there were also some honeybees competing with the native bees at the flowers 😦
I have never seen so many Leioproctus bees together at the same time! It was amazing! This certainly supports our idea that these bees can survive in stasis underground – as pupae probably – for extended periods (multiple years) to survive through drought periods. We didn’t see these bees before or after the Astrotrichas were in flower. Nor did we see them in the 2019 season, at the height of the drought, but only in 2020 after good rains. Many Leioproctus species are specialists, such as the Persoonia bees, so it is possible these ones we saw on Astrotricha roddii are specialists on this plant species. This species of Leioproctus has been collected only a few times in the past.
Figure 2. A megachilid bee on Astrotricha roddii, with a great load of pollen.