The Wasp and the Orchid: A Remarkable Partnership

“She was the foremost female naturalist of her generation. Today she is almost entirely forgotten, save by a handful of scientists and naturalists,” writes author Danielle Clode of Edith Coleman – a remarkable Australian who solved the mystery of orchid pollination (even Darwin was stumped!), was the first woman to be awarded the Australian Natural History Medallion, and was one of Australia’s foremost orchid experts.

For over 20 years Danielle has been researching Edith Coleman in an attempt to understand and celebrate the life of this very remarkable woman. The Wasp and the Orchid: the remarkable life of Australian Naturalist Edith Coleman, published by Picador tells Edith’s story in both Danielle and Edith’s words – it’s a fascinating and entertaining read. Here’s an excerpt from the book, an essay by Edith on the wonders of orchid pollination. What a woman!

The Wasp and the Orchid: A Remarkable Partnership
By Edith Coleman, first published May 14, 1927 in The Age newspaper.

Instances of Nature’s wonderful partnerships in the plant and animal worlds are not at all uncommon, but recent discoveries have disclosed a singular alliance between an orchid and a certain wasp which is so strange as to appear incredible. The purpose of the partnership has so far baffled experts both in orchidology and entomology.

One learns to be surprised at little in Nature’s realm, and, though many of her ways are inscrutable, we accept them without question.”

Some of the means she adopts to achieve her ends are altogether beyond our ken, and none are more marvellous than her modifications and adaptations to ensure reproduction in plants and animals. Having satisfied herself that cross-pollination would add vigor to many of her plants, she set about teaching them wonderful lessons in adaptability, modifying their structure to suit the transport of pollen. The square peg was, metaphorically speaking, made to fit the round hole, and in certain plants we can follow many singular evolutions as they adapt themselves to pressing needs or changed conditions.

Flowers have endless contrivances by which insects are invited, often compelled to carry out this work of cross-pollination, and among the orchids we find some of the most remarkable of these – many so wonderful as to appear incredible and others so strangely beautiful as to compel our instant admiration.

Illustration courtesy of Danielle Clode

Of the many interesting partnerships in the plant world there are some that might well be cited as object lessons in co-operation, in which the articles of association are rigidly adhered to, and where the benefit of each member is assured. In some old-established co-operations between plants and fungi both partners draw fixed dividends.

In other plant–fungi alliances the benefit to the plant is evident, though we are not quite so satisfied as to the nature of the quid pro quo for the fungi. We are all familiar with the association between insects and pollen-bearing plants. In the case of bees and owers the purpose of the partnership is plain. In exchange for nectar and pollen the bee performs the service of pollination. Certain wasps undertake the same offce in payment for nectar. But in the case of the orchid (Cryptostylis leptochila) and the wasp (Lissopimpla semipunctata), Nature seems to have excelled herself in her strange methods of achieving her results. Strictly speaking the insect is not a wasp, but belongs to the family of ichneumon flies which parasitise the larvae of other insects. Some of the males do occasionally visit owers in search of nectar, but in the case under question neither egg-laying nor nectar-feeding was the object of the visits.

Instead of entering the owers in the orthodox way, thus removing the pollen on its head or back, the insect was observed to enter the ower ‘backwards,’ and emerged with the pollen on the end of its abdomen – always in exactly the same position!”

Having satisfied ourselves that this was actually taking place we set about to discover the purpose of such an unusual partnership, the object of the wasp’s visit – the payment it exacted for the service it undoubtedly rendered the orchid.

Close observation showed that the insect evinced no interest in the nectar secreted by the ower, for its head was always turned in the opposite direction; and careful search failed to reveal any larva imbedded in the ower in which it might deposit its egg; and which would act as host to its offspring in its larval stage. We took nothing for granted, and though we felt confident that our wasp was too wise to risk its egg in vegetable matter which might dry long before her larva reached maturity, we made a careful examination of the viscid matter of the orchid, but the microscope showed nothing that we could isolate as an egg.

Then came our biggest puzzle, for a leading entomologist identified our insects as males, so that the egg-placing theory fell through, and we could lay hold of nothing but the one outstanding fact, new, we believe, to science, that the ichneumon fly does, in this unusual manner, perform faithfully the service of pollination for the orchid. It would appear to be a perfect partnership for which the orchid has specially modified its shape.

There is no apparent search on the part of the insect for either nectar or caterpillar, or any evident choice of ower.

Possibly possessing keen eyesight or a wonderful sense of smell, the wasp flies directly to the ower selected, taking up the necessary position so easily and surely that one feels it must be answering some natural impulse, whether calculated or mechanical, or obeying some powerful urge.”

As the orchid matures and when one concludes the moment has arrived for the services of the wasp, the labellum of the ower assumes a strange curve – curiously adapted, one would say, to the needs of the wasp, suggesting a vegetable intelligence that knows and plays upon ‘the passion of insects’. As an instance of insect cunning or obedience to some involuntary prompting it appears unparalleled.

It is without doubt a strange partnership and the benefit to the wasp is still shrouded in mystery.

The solution is no doubt simple when it is worked out, but the season of the orchid having closed further investigations are held up for some months.

This extract is featured in The Wasp and the Orchid by Danielle Clode, published by Picador. RRP $39.99 AUD. Buy here.

Featured image by Georgina Reid of a spider orchid (Caladenia spp.) photographed near Wave Rock in Western Australia.