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It depends how you look at it

October 23, 2020

One group of the plants flowering at the moment, if you are looking carefully are Australian bush orchids. They come in a vast array of shapes, sizes and colours. Most orchids replicate by producing seed and for this to happen they need to be pollinated. Some species self-pollinate but the majority rely on insects to do this task. Most orchids however do not produce nectar or pollen with which to attract the insects but instead use various deceptions to lure them. These generally take two forms, food deception and sexual deception.

Orchids that use food deception look like plants that provide insects with pollen or nectar. The Common Donkey Orchid (Diuris orientis), pictured above, mimics the bush-pea flowers of the Fabaceae family, for example Common Bossiaea (Bossiaea prostrata), pictured right. The orchid flowers are larger than the pea flowers thus creating a more visible target for nectar-seeking insects.

Orchids that use sexual deception have petals that look like female insects. The flowers emit a pheromone that attracts the male insect who then proceeds to ‘pseudo-copulate’ with the orchid petal. The Orchid Dupe Wasp (Lissopimpla excelsa), pictured below, is so named because it is one of the insects deceived.

This wasp, a native of Australia, ‘mates’ with plants of the genus Cryptostylis, the Tongue Orchids. To the human eye the orchid petals are similar in colour to a female wasp. However to the visual system of a wasp, more in the green, blue and ultraviolet range, the similarity is more striking.

It depends how you look at it.

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