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New research uncovers the sweet secrets of the Candy Spider Orchid

Our Orchid Conservation Program is world-leading and touches on every aspect of orchid conservation. Our expert scientists work on over 30 different species of orchid, but this week, our scientists, in collaboration with the Australian University and University of Western Australia, published a paper that may provide helpful insights into the conservation of Candy Spider-orchid (Caladenia versicolor).

This formerly wide spread species of orchid is now endangered and now only found in small numbers in a few locations in Victoria. Unfortunately, the distribution of the Candy Spider-orchid has been in decline due to threats from habitat loss and animal grazing.

New research from Royal Botanic Gardens Victoria

This week, Dr Noushka Reiter and her team collaborated with the Australian University and University of Western Australia, and published a paper in the Botanical Journal of the Linnaean Society that provides vital information in the conservation of this species.

They found that this species of orchid was almost solely pollinated by male Leioproctus platycephalus bees – 97.5% of visits were by this species to be precise, with the majority of them being male. This suggests that the orchid has what we call a ‘specialisation’ with one species of bee pollinator.

Another unexpected result is that the Candy Spider-orchid was not previously known to produce nectar to attract bees. Instead, they were thought to be ‘food deceptive’, meaning that they did not produce a sweet nectar reward for their pollinator, but only deceptively looked and smelt like they did. However, upon investigation the team found that it actually does produce very small amounts – which the Leioproctus platycephalus bees foraged on.

Dr Noushka Reiter in the field

Dr Noushka Reiter in the field

What does this all mean?

First, this research shows that although we assume some orchids don’t produce nectar, they actually might. This could lead to many more investigations into other orchid species that are previously thought to be only ‘food deceptive’.

Secondly, being aware of this specialised relationship between Leioproctus platycephalus bees and the Candy Spider-Orchid can be very helpful in the creation of conservation management plans for this orchid species. One clear outcome was that to conserve and reintroduce the orchid, it is also vital to conserve the bees.

At present, Leioproctus platycephalus bees are still common throughout Australia, but conservationists should always make sure that their populations are taken into account when they are trying to conserve the Candy Spider-orchid.

Before this study, no Spider-orchids were known to have specialised pollination with just one bee species. So this amazing research has opened up a whole range of new opportunities for this beautiful group of orchids and their conservation.

 

 

If you are interested in reading the paper on this research, please see the journal paper here.

If you would like to support the work of the Orchid Conservation Program, please consider making a tax-deductible donation through the Royal Botanic Gardens Victoria Foundation.

We would like to thank the following funders and organisations for supporting research and conservation of this species. Victorian Threatened Species Initiative Grant and National Landcare Programme funding through the Wimmera Catchment Management Authority. Parks Victoria, DELWP and Trust for Nature for access to property; the Australasian Native Orchid Society Victoria group for assistance in planting the conservation translocation sites.


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