Caladenia drummondii, the winter spider orchid is an enigmatic and beautiful orchid, which I was privileged to see east of Narrogin last week. Unfortunately the spot remains secret because they are uncommon, and someone had already dug up a plant there.
The location had leaf and bark litter on a loamy gravel slope of Eucalyptus neutra (Newdegate mallee) . Flowers are tiny and exquisite, but so well camouflaged that it is very easy to walk over them without noticing. There were a couple of white variants as well.
The winter spider orchid intrigues me. It is the earliest flowering spider orchid, which flowers in unforgiving terrain at a risky time of the year, when rainfall is variable and there are few pollinators or other flowers.
They observed only males, which approached the flowers in a mating pattern. This suggests that it is being attracted to the orchid by a pheromone.
Adult flower wasps feed on flower nectar, which poses a problem for their survival in late autumn. Researchers found that the winter spider orchid labellum has a higher sugar content, and the calli are sticky. This is another attractant for the wasps, which can lop the labellum. In the two years studied, only 2% and 10% of the orchids produced seed.
I found a fly on one orchid, which was loathe to leave it despite gentle poking. I doubt that it is a pollinator, possibly resting overnight.
I was surprised to also see an ichneumon wasp nearby. Wasps are obviously not restricted to warm months.