Secrets of the orchid mantis revealed – By James Gilbert


Secrets of the orchid mantis revealed – it doesn’t mimic an orchid after all

By James Gilbert, University of Sussex

In his 1879 account of wanderings in the Orient, the travel writer James Hingston describes how, in West Java, he was treated to a bizarre experience:

I am taken by my kind host around his garden, and shown, among other things, a flower, a red orchid, that catches and feeds upon live flies. It seized upon a butterfly while I was present, and enclosed it in its pretty but deadly leaves, as a spider would have enveloped it in network.

Orchid mantis: Hymenopus coronatus
frupus, CC BY-NC

What Hingston had seen was not a carnivorous orchid, as he thought. But the reality is no less weird or fascinating. He had seen – and been fooled by – an orchid mantis, Hymenopus coronatus, not a plant but an insect.

We have known about orchid mantises for more than 100 years. Famous naturalists such as Alfred Russell Wallace have speculated about their extraordinary appearance. Eschewing the drab green or brown of most mantises, the orchid mantis is resplendent in white and pink. The upper parts of its legs are greatly flattened and are heart-shaped, looking uncannily like petals. On a leaf it would be highly conspicuous – but when sitting on a flower, it is extremely hard to see. In photos, the mantis appears in or next to a flower, challenging the reader to spot it.

Hiding in plain sight?

On the face of it, this is a classic evolutionary story, and a cut-and-dried case: the mantis has evolved to mimic the flower as a form of crypsis – enabling it to hide among its petals, feeding upon insects that are attracted by the flower. Cryptic mimicry by predators is well known. For example, crab spiders camouflage themselves against a flower, and can change from yellow to white to match their host flower.

Crab spider (Misumena vatia) with wasp prey.
Olaf Leillinger/Wikimedia

The orchid mantis is something of a poster child for such cryptic mimicry. So obviously true is this evolutionary story that it is often discussed today as established fact.

No one seemed to have noticed that there has been no evidence to support this hypothesis. Orchid mantises are actually very rare in the field, so their behaviour is hardly known about, except in captivity. For example, nobody knows exactly which flower the mantis is supposed to mimic.

Now a set of new studies by James O’Hanlon and colleagues shows quite clearly that we’ve been getting it wrong all this time. While it is indeed a flower mimic – the first known animal to do this – the orchid mantis doesn’t hide in an orchid. It doesn’t hide at all. And to an insect, it doesn’t even look particularly like an orchid.

A deadly lure

O’Hanlon and colleagues set about systematically testing the ideas contained within the traditional view of the orchid mantis’ modus operandi. First, they tested whether mantises actually camouflage amongst flowers, or, alternatively, attract insects on their own. For a flower-seeking insect, as predicted, the mantis’ colour pattern is indistinguishable from most common flowers.

However, when paired alongside the most common flower in their habitat, insects approached mantises more often than flowers, showing that mantises are attractive to insects by themselves, rather than simply camouflaging among the flowers.

“We can clearly observe insects, like bees, diverging from their flight paths and flying right towards this deceptive predator,” O’Hanlon told me. “These beasties are marvellous for this kind of question, because we can observe a dynamic interaction between predators and prey.”

This phenomenon, known as aggressive mimicry, occurs in other animals. The Bolas spider releases chemicals that imitate sex pheromones released by female moths seeking a mate. Male moths, with their elaborately plumed antennae, can detect these pheromones from miles away, and are lured in to their death. Carnivorous Photuris firefly females can mimic the flash-responses of a different species of firefly, attracting amorous males who find themselves on the menu.

Next the researchers assessed where mantises chose to sit. Surprisingly mantises did not choose to hide among the flowers. They chose leaves just as often. Sitting near flowers did bring benefits, though, because insects were attracted to the general vicinity – the “magnet effect”.

Any old flower

When they compared the mantis’s shape and colour with flowers from an insect’s perspective, the predator did not resemble an orchid or indeed any particular species of flower, but rather a “generalised” flower. This fits with what we already know: some of the best mimics in nature are imperfect mimics with characteristics of several “model” species.

Placing experimental plastic models out in the field, the researchers found that mantis colour was much more important than shape in attracting insects. They believe that mantises may not actually precisely mimic a particular kind of flower. Instead they may exploit a loophole created by evolutionary efficiency savings within the insect brain.

Jumping to conclusions

As humans with giant, hyper-developed brains capable of abstract thought, we have the luxury of being able to make decisions using all the available information. After a few seconds of scrutiny, what initially looks like a flower because of its colour begins to look suspicious – and once we spy bug eyes and a vaguely insectoid outline, the game is up: it’s a mantis.

But a tiny insect zipping around on the move, with its compact brain, cannot afford such cognitive extravagance. It has a shortcut – a rule of thumb: anything matching colour X is a nectar-containing flower. More colour equals bigger flower, with potentially more nectar. No cross-checks, no two-step authentication. The mantis takes advantage of this shortcut by using “sensory exploitation”. It is a concentrated mass of the right colour – a supernormal stimulus. The insect classifies the mantis as a giant nectar-filled flower and approaches to investigate – to its doom.

“This work is terrific,” Martin Stevens of Exeter University, an expert on animal deception and mimicry, unconnected with the work, told me. “It’s wonderful to see something that Wallace and others discussed so long ago, finally tested experimentally.”

Colour me beautiful: an orchid mantis nymph devours its prey
Igor Siwanowicz

This is not the first species to lure in prey with sensory exploitation. The white crab spider reflects strongly in the UV, making it highly conspicuous to wandering insects. But the spider still “hides” on a flower. Surprisingly a flower with a crab spider is more attractive than one without: the crab spider mimics UV-reflective floral patterns that guide insects to nectar. But the orchid mantis is the first animal ever shown to mimic an entire flower, attracting insects on its own.

There is one remaining issue, though: if the mantis can attract insects by sensory exploitation alone, muses Stevens, then: “Why have body parts that look like petals? My guess is that the pollinators are initially attracted at a distance through sensory exploitation, but then more accurate mimicry kicks in at close range, when the insects can inspect the mantis more closely for what it is.”

Greg Holwell, who coauthored the study, told me: “What this work really emphasises is that working on a completely unstudied species can produce fascinating results. Getting out there and starting with some solid natural history helps to generate hypotheses that you can subsequently test with field experiments, and can lead to the discovery of completely novel phenomena.”

“While important discoveries are made from laboratory research on model species like fruit flies, every species has an exciting story to tell and can help shape our understanding of how the natural world works.”

The Conversation

This article was originally published on The Conversation.
Read the original article.


Conference posters: Less is more!

For some it’s the highlight of a conference, for others it’s a dull chore – the poster session. Unfortunately giving a poster presentation at a conference sometimes comes with the stigma of not making the cut for the oral presentation sessions. But conferences aren’t just about sharing your work; they are about making career forming connections with your peers and seniors. And for someone like me who is terrified by the mere thought of trying to make small talk with strangers over the tea and coffee table, the poster sessions are a perfect opportunity to just walk up to someone and say ‘hey, talk to me!’.

If you have a poster session coming up think about how you can make the best impression, and what’s the best way to get people talking about you and your work. A few years back I won the first place prize out of the several hundred poster presentations at the International Behavioural Ecology Congress in Lund, Sweden. Since then I’m often asked for tips on making poster presentations so I thought I would share some of the philosophy behind the creation of this poster and some of the feedback I received after presenting it.

Here is the poster and the research it refers to can be found openly available here.


The golden rule: Less is more

The worst possible poster is one that consists of huge blocks of text. If I can’t understand what your poster is about with a cursory glance I’m probably not going to bother reading it. The most common feedback I had on this poster came from people simply saying ‘I love it, I don’t have to read anything’. If your posters have a series of paragraphs on it, either go through and stream line it as much as you can, or completely rethink how you approach your paper. The fundamental purpose of research is to answer a question. This poster takes that fundamental idea to an extreme by simply having two sentences, a question and an answer.

It may feel a little weird to streamline your story so much, after all it usually represents several years of hard work. But as I will explain a little bit further on, the poster session isn’t just about the poster, its about you. You have the opportunity to stand next to it and talk as much as you like. Make your poster as succinct and direct as possible, if anyone wants further details they can ask you as many questions as they like.

Another cliché that works: A picture says a thousand words.

A huge contributor to the success of this poster is the big picture in the middle of it. I could have written a paragraph of information about mimicry theory, deception, sensory ecology and what sort of animal the orchid mantis is. But the big picture in the middle does all that for me. People can simply look at the picture and immediately understand that we have a predatory insect that looks like a flower. I then ask the question of whether by looking this way it deceives pollinators. A picture of an orchid mantis devouring a bee immediately answers that question without needing to explain it in words. The single (and simple) graph helps enforce the main finding of the paper, which was that orchid mantises can attract even more pollinators than flowers.

Think of what images you can use and let your pictures do the talking. Get rid of those unsightly blocks of text and make everything as self explanatory as possible. Hopefully you will find more people reacting positively to your succinct and well-designed poster. It will take some creative thinking but that’s the fun part right?

A poster is not a paper

There is an out dated perception that posters have to resemble truncated papers with introduction, methods, results and discussion sections. I have even seen posters with the whole bottom half taken up by references, footnotes and funding acknowledgements. I was horrified to hear that there are some conferences that have strict requirements that posters must adhere to manuscript formats and even specify font types and styles. If you are attending one of these conferences you have my deepest condolences. Best hit the sauce and make the best of it.

For most of the conferences I have been to the extent of poster requirements is their dimensions, so the design is a limitless playground for you to work with. Forget about your manuscript and think about your story. What is the story you want to tell and what visual aids do you need to tell it? Go bananas, get creative, and remember your poster is just a tool to help tell your story.

It’s all about you.

Maybe I am just getting old and grumpy but I have stopped reading posters all together during conference sessions. I simply walk up to the person standing next to it and say ‘what’s the go smarty pants?’ Having someone talk me through their research and tell me what they did is so much more engaging and makes the poster sessions so much more fun than even the most well organised symposium, and definitely more fun than a plenary session.

Remember that a poster session is your opportunity to sell yourself as a professional. The poster is simply a tool for you to help engage with your audience. If someone is reading your poster, don’t stand there expectantly staring at them waiting for them to ask a question. It makes you look creepy and it makes them very uncomfortable. Don’t let them read it, interrupt and ask them if they’re would like to hear your story. Be prepared to do a hell of a lot of talking and make sure you have fun.

Once you are busy telling your story the poster is just there to give you something to point at. As said above think about what visual aids you need to tell your story – a particular graph you are likely to refer to, or a photo of your plant/animal/fungus/study site/whatever. Forget everything you’re used to seeing on posters, like references, acknowledgements and methods sections, and make your poster a story telling tool.

Think outside the poster

Your poster presentation doesn’t have to end at the poster. I decided to stick in a QR code that led people to this very website. It even managed to draw in a few people who simply wanted to know what the strange black and white box was and how it works. Others may simply put up a website link or recommended search terms. Now that QR codes are out of fashion I cant wait to see poster designers start using augmented reality apps to help their stories jump off the page.

Don’t forget you can also bring a heap of other story telling tools with you. I went a bit overboard with this particular poster session and brought an iPad loaded up with extra figures, pictures and videos so that I could present my entire PhD thesis if anyone cared to ask. I’ve seen people brandishing stuffed animals, preserved specimens, even bags of lollies to lure in passers by. If nothing else it could be a nice ice-breaker, so have as much fun with your supplementary materials as you are comfortable. Feel free to bring a stack of business cards and hand them out like its Christmas because this is your time to shine!

If you have seen some other great posters or poster techniques I would love to hear about them. If you have any other great tips share them here, or if these techniques have worked for you I would love to hear about it! Enjoy your poster session, because it is what you chose to make it. So make it kick ass!

Brutal Biology Podcast

There is a new science podcast doing the rounds specifically aimed at biologists with a sweet tooth for metal music. The appropriately named Brutal Biology features a prominent scientist/researcher/thinker each week and focuses on getting to know the person behind the ideas and the research. So what starts off as a scientific discussion often diverges into personal stories and obscure conversations interspersed with explosions of hard-core metal.

And just in case you needed an extra reason to check it out, I am on it this week! We discuss everything from research and university culture, to video game developers as artists. Check it out below or on SoundCloud and keep up to date with Brutal Biology on Twitter and Facebook. Just make sure you have your fingers on that volume dial because those musical interludes can get the jump on you!

3D printing an orchid mantis

I just finished up a four month stint as a research fellow at the National University of Singapore. Whilst there I worked towards increasing the capacity to do orchid mantis research using model stimuli.

Flying insects such as bees and butterflies are lured towards the flower like orchid mantis. Bees can be observed making back and forth inspection flights in front of and within capture distance of orchid mantises. I recently showed that these behaviours could be stimulated by presenting wild pollinators with artificial orchid mantis models. Using artificial models allows me to manipulate the signals presented by the orchid mantis so that I can conduct experiments to understand how different aspects of their colour and morphology affect pollinator behaviour.

mantis copy
Preliminary sketches of a sub adult female Hymenopus coronatus.

I started off by putting together some scale drawings of a sub adult female orchid mantis based on photographs I had previously taken. Then using these reference drawings I sculpted a 3D model using the open source software Blender.

Once I had my 3D sculpture I worked with the 3D printing company Shapeways to print out the final models. The model had to go through a few iterations as the delicate legs of the orchid mantis were pushing the limits of how thin the 3D printers could actually produce. With a printable prototype in hand I then started working on the making several different versions to use as treatments in field experiments.

The experiments are ongoing and are likely to take a while. Conducting field work in Malaysia is difficult, especially when you are based in Australia. For now you can get your 3D printed orchid mantis kicks by purchasing your very own 3D printed mantis! I put together a larger more robust model based on the experimental models and have made it available online.

Follow this link to check out the orchid mantis models available for sale. I recommend the strong and flexible plastic materials as the model, although larger than the real thing is still very delicate. The models take a few weeks to produce and keep in mind they are posted from the US so postage is the most expensive part. Check out the rest of the Shapeways site and stock up on wacky 3D printed goodies to make the postage costs worthwhile 🙂

Now that I have the Shapeways store up and running I am working on putting together some more science/zoology themed designs that I will be prototyping and making available soon!

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Endeavour Research Fellowship

I am off on a new adventure! I was offered an Endeavour Research Fellowship by the Australian Government to conduct research in Singapore. For the next few months I will be based at the National University of Singapore conducting research in Daiqin Li’s Behavioural Ecology and Sociobiology Lab. What will I be researching? Why the orchid mantis of course! I just cant seem to stop asking questions about it! I will keep posting updates on the project and other wonderful Singaporean experiences that come my way.