Mimicking the mimickers

Researchers have used 3D printing and artificial flowers to find out exactly how a type of Dracula orchid deceives flies into pollinating it, by pretending to be a mushroom.

The shade-loving, tree-dwelling species, Dracula lafleurii, can be found in the cloud forests on the slopes of the Ecuadorian Andes. It often grows close to mushrooms, and resembles them in shape, colour and scent. This Dracula orchid is pollinated by small drosophilid flies normally associated with mushrooms – in mimicking the mushrooms, it is recruiting flies to help it to reproduce. The question is: is it the looks, or the smell?

Melinda Barnadas creating the prototypes for the artificial flowers used in the study. Temporary studio located deep in the Ecuadorean cloud forest at Reserva Los Cedros. Photograph: Melinda Barnadas.

Melinda Barnadas creating the prototypes for the artificial flowers used in the study. Temporary studio located deep in the Ecuadorean cloud forest at Reserva Los Cedros. Photograph: Melinda Barnadas.

Research published in New Phytologist shows how, by mimicking the mimickers, scientists have been able to untangle the visual and scent components of the Dracula orchid’s appeal to figure out what makes them so good at fooling flies into pollinating them. Using 3D printing to make realistic artificial flowers, which copied the real thing in colour and scent, Tobias Policha and colleagues experimentally separated the cues used by the Dracula orchid to lure in flies.

The researchers found that a particular feature of the Dracula orchid – its mushroom-like labellum – worked together with its mushroom-mimicking scent to attract flies by exploiting their visual and chemical preferences. In doing so, it ensures regular visits and pollination by the flies. Without mimicking the mimickers using their 3D printing technique, the researchers would not have been able to work out the secret of the Dracula orchid’s devious attraction.

This is the original draft of a press release published via the Wiley news room, and appears in edited form as a blog post on the New Phytologist Trust blog.

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Shy flowers attract fewer moths

Plants that have flowers that point towards the sky may be better at attracting pollinators than plants that have ‘shy’ flowers that point sideways. The study, by researchers in the USA, Germany and South Africa, used two species – Zaluzianskya natalensis and Zaluzianskya microsiphon – to investigate the idea that flower orientation, in combination with floral scent, affects the behaviour of pollinators.

Extract from Fig. 1 in the article, showing Zaluzianskya natalensis being visited by the hawkmoth Hippotion celerio.

Both flowers are open in the evening, and attract hawkmoths, which pollinate them. In the experiment, hawkmoths showed a preference for Z. natalensis flowers. Z. natalensis produces more floral volatiles than Z. microsiphon – it has a stronger scent to pollinators – but artificially adding more volatiles to the flowers had no effect on the numbers of hawkmoths that visited.

The secret of Z. natalensis’ success doesn’t appear to be its smell. Z. natalensis, however, also has flowers that point upwards. The researchers found that manipulating the flowers of Z. microsiphon to point upwards increased their appeal to hawkmoths, and that manipulating the flowers of Z. natalensis reduced their appeal.

This study, published in New Phytologist, shows the importance of flower orientation in affecting how pollinators behave, which in turn influences the reproductive isolation – the chance of inter-breeding – that those plants experience.

This is the original draft of a press release submitted via the Wiley newsroom, and appears in edited form as a news post on the New Phytologist Trust website.