Identifying pollinators to inform reintroductions

Understanding the ecology of orchids is of critical importance to their conservation and reintroduction. Orchids often have complex relationships with their insect pollinators. Understanding these relationships is necessary to understand the broader ecological needs of threatened orchids. While some species (Gnat-orchids, Cyrtostylis) do offer nectar rewards, others (Sun-orchids, Thelymitra) achieve pollination by pretending to offer a reward – food deception. The flowers of many species (some Spider-orchids, Caladenia) go even further – they trick male insects into attempting to mate with the orchid flower by releasing the same scent as the female insect – in doing so the pollinator removes and deposits pollinia thus facilitating pollination by sexual deception. Others, such as some Helmet-orchids (Corybas) trick female gnats into thinking the orchid flower is a mushroom that the gnats lay their eggs in – brood site deception. The relationships between orchids and their pollinators are truly remarkable.

The example of recently completed works listed in the puclications below of the sexually deceptive Caladenia hastata (Melblom’s Spider-orchid), shows how crucial it is to know if the pollinator is present prior to reintroduction. The orchid has now been reintroduced into both of the sites where the pollinator has been confirmed and natural pollination and seed set has occurred.

Pollinator research projects:

  • Identification of orchid pollinators from sexually deceptive species of Caladenia from across Victoria. This is a fantastic citizen science project. These findings have implications for the conservation of our orchids and their pollinators.
  • Caladenia arenaria (Sandhill Spider-orchid), Caladenia concolor (Crimson Spider-orchid) and Diuris callitrophila (Oaklands Diuris) identification and detection of pollinators at both sites and potential reintroduction sites.
  • Caladenia formosa (Elegant Spider-orchid) survey for pollinators and potential reintroduction sites.
  • Indentification of pollinators and pollination mechanism in Caladenia versicolor (Candy Spider-orchid) and Caladenia colorata (Coloured Spider-orchid).
  • Identification and presence of the pollinator at both the wild site and potential reintroduction sites of the Pterostylis basaltica (Basalt Greenhood).

Project team

  • Dr. Noushka Reiter (Royal Botanic Gardens Victoria)
  • Marc Freestone (Royal Botanic Gardens Victoria)
  • Volunteers: Ms Eve Almond, Assoc. Prof. Charles Young, Prof. Peter Wallace, Mr Mike Wicks and Mr Neil Anderton (Royal Botanic Gardens Victoria)
  • Volunteers (Australasian Native Orchid Society - Victorian Group)
  • Collaborators: Dr. Ryan Phillips (Australian National University), Prof. Rod Peakall (Australian National University), Dr. Graham Brown
  • Student: Mr Nicholas O'Brien (Deakin University)

Support

  • Australian National University
  • Australian Native Orchid Society
  • Department of Environment, Land, Water and Primary Industries
  • NSW Office of Environment and Heritage (Saving our Species Program)
  • Parks Victoria
  • Trust For Nature
  • Wimmera Catchment Management Authority

Publications

Reiter N, Vlcek K, O’Brien N,  Gibson M,  Pitts D, Brown G, Bower C and Phillips RD (accepted August 2016). Pollinator rarity limits re-introduction sites in an endangered sexually deceptive orchid: implications for plants with specialized pollination systems. Botanical Journal of the Linnaean Society.