The Resilient Postdoc: Keep the exit rows clear at all times.

If you are seated in an emergency exit row you may be called upon to assist crew members in the unlikely event of an emergency evacuation.

Those who contemplate disaster may enjoy the extra leg room. Thankfully, the probability of any given academic career stalling and rapidly losing altitude is orders of magnitude higher than it happening on your average flight, but my conceit is simply to make the point that preparing for emergency leads to a more comfortable ride. The same can be said for bunker-dwelling, tin-can stockpiling Doomsday Preppers, who are easy to make fun of, except that their backs must be stiffened by a dose of confidence inspired by addressing their perceived existential threat.

In this uncertain and hyper-competitive job market with falling availability of research-focused academic positions, if a postdoc is not preparing to walk away every two or three years they’re a star-performing outlier, or blissfully unaware. It is shocking therefore how often I have encountered postdoc research scientists who simply have never thought about how to get a job outside of their narrow research domain. This should start in their PhD years. In fact, in light of the harsh jobs climate in research, it is unethical for a supervisor or university department to be ignoring the pressure for postgrad students to develop career capital that can serve them and the community outside the narrow field of academic research.

At the end of my first postdoc in 2015, I was beset by anxiety blooming from the combination of scarce opportunities and academic job rejections. I needed to look beyond academia and it took me months to refine strategies to identify jobs that I might be capable of getting an interview for. Eventually I got an interview for a government department, which turned into a job offer. It sounded like an ok job, I didn’t end up taking it, but the fact that I had been offered a decently paying position after successfully marketing my unique set of skills was strong salve to my career anxiety. It gave me some confidence that I could walk away when I needed to.

The chart below shows every ongoing role I’ve applied for since completing my PhD in 2013. As you can see, I have applied for 15 ongoing university academic roles in the past six years and received exactly one interview. Contrast this to the ongoing non-academic government jobs I’ve applied for (five), where I’ve attracted two job offers—a substantially higher strike rate! My research is not easily and directly tied to government priorities, so I’d argue that my single case study supports the assertion that the world outside the ivory pressure cooker is wide and full of opportunities.

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I have applied for 24 ongoing jobs since 2013. My two job offers have come from non-academic government roles, for which I have only made five applications. (Scroll below article to see the same visualisation for fixed-term applications)

In light of my experience, this post is for academics who want some pragmatic advice on accessing the diversity of alternative careers.

– Learn to job hunt. You might not have ever used non-academic modes for job-hunting, you might be baffled as to what keywords will find you relevant positions, and one of the big uncertainties is often not knowing what’s available to you. So take the time to learn how to drive the commercial job advertisement search engines, as well as the relevant government and industry outlets. From the Australian point of view, this means Seek.com.au, federal, state, and local government job sites. Spend time using all the keywords you can think of, learn which ones are productive, then set auto-alerts for these (e.g., keyword “plant” was useful to me). Doing this, you will probably learn about interesting jobs you never knew existed.

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Actually there are no jobs in “speciation”. Four employers misspelled “specification”.

– Scan for jobs early and often. Start looking early. Earlier than you think is necessary. Repeat your jobs search regularly, at least once a fortnight. Make it a part of your weekly routine, or spend time doing this instead of wasting time online on a demotivated Friday afternoon. It’s really not arduous. This ongoing jobs market research will a) arm you with information about the reality of the jobs market before you need it, and b) identify opportunities that might sound attractive now, perhaps even worth leaving a postdoc for. Don’t miss out on a promising alternative career opportunity because you weren’t paying attention.

– Learn to apply for non-academic jobs.This is a big one, and something you want to practice well before your first “must-get” job. Other industries have their peculiar CV or resume formats, and virtually no industry has CV conventions like academia. Learn to craft a CV targeted to the job/industry. For example, consider adding a “skills and expertise” section highlighting your strengths and transferrable skills. While you might need to completely overhaul your academic CV, that doesn’t mean you have to avoid mentioning all your papers or teaching. Just re-phrase and perhaps contract the detail. For example, I reduced my teaching experience to eight lines on a recent CV because it offers evidence of important skills, but the detail of subjects taught and years of experience don’t matter outside tertiary teaching. Learning to apply for non-academic jobs is learning to market your skills to a non academic audience. A PhD and postdoc in science equips you with a diversity of useful skills, but you have to translate them into the keywords that employers want to hear. Examples of skills most STEM academics can speak to include:

    
Communication Analytical Management: projects & people Technical
Writing complex and technical subject matter for specialists

Communicating complex and technical concepts to non-specialists

Professional oral presentation and seminars

Grant writing

Tertiary teaching to a diverse student population
Research and synthesis of specialist and technical information

Critical thinking

Higher order logic and reasoning

Executing sound professional judgment from expert knowledge

Conducting and interpreting statistical analysis

Experimental design

Rigorous attention to detail

An ability to quickly assimilate new and often complex information

Managing complex and competing priorities

Supervision and mentorship

Communicating with influence, in writing or in person

Working effectively in teams, building and maintaining collaborations

Working independently with minimal supervision, demonstrating initiative

Careful and effective stakeholder engagement

Programming skills

Laboratory skills

Field skills

Data visualization

GIS

– Practise applying. Even if you don’t think you’ll take the job, apply anyway. If you’re offered an interview, you might find out information that changes your mind on accepting the job. If you’re offered a job, whether or not you accept, I guarantee this will make you feel better about possible future academic extinction.

– Arm yourself with skills for your desired job. See a job you like, but can’t fulfil the selection criteria? Great. Now you know what you need. Find the time during your postdoc to develop some of these skills. Craft yourself as a candidate for the job you want, ideally by building skills that you can apply to your research now. The counter to this is: Avoid sinking time into skills that are not marketable outside academia. This is a tough line to walk, because some skills that might serve you in research are a hard sell on the outside. For example, learning to master that peculiar and poorly-written R package for detecting hybrids in polyploid organisms, or the latest technique for extracting DNA from sub-fossil sea-urchins might be useful for your research program now, but long-term useless. Can you get a collaborator on that, and instead spend time learning general stats and programming skills to analyse and visualise the results?

– Network, and learn from others. Don’t just sit on the internet reading quit-lit. Tee-up coffee meetings with other scientists who have made the jump. Ask them the obvious and practical questions you think sound dumb. Meet for coffee with people you don’t know who work in the jobs markets you want to explore. Find out: where are the jobs?, how are people getting them?, what are the attractive things about the job you might be overlooking?, what are the negative things you might be overlooking? Networks pay off in unforeseen ways. A 30 minute coffee meeting with someone new is never a wasted 30 minutes.

– Share job information, help each other! Whether or not it’s an academic job, keep your close colleagues and collaborators in the loop. While an isolated job ad can be zero-sum, you operate in an environment of repeated opportunities that is certainly not zero-sum. If you’re applying for a lectureship, don’t let it pass by your postdoc colleagues, share the job ad (but only to the nice, supportive, friendly ones). If you don’t get the position, you’d prefer they got it than a stranger, right? If you see an attractive non-academic job that’s not for you, pass it on to that postdoc colleague who seems like a good fit, even if they are not looking for jobs. A small network of colleagues helping one another catch the opportunities that fall through individual nets.

Overall, the most important and productive thing is to prepare yourself for an exit before you need it, even if you never need it. Taking concrete and practical steps towards building a safety net will give you confidence working under uncertainty. Even if you stay in academia your whole life, never having to break the emergency glass, planning for the event will be invaluable experience to pass on to your future students.

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All 16 fixed-term roles and fellowships I have applied for since 2013.

 

Project update: Contrasting bird and insect pollination through use of novel camera and genetic technologies.

I recently put together some material on my work for the University of Melbourne open day. As a teaser for the papers in current preparation, here’s an abstract and some visuals on the project.

While we simply do not know what pollinates many of Australia’s plants, there is good evidence emerging showing Australia to be a global hotspot for bird-pollination. This raises questions about what ecological and evolutionary factors might encourage plant lineages to adapt to use birds as couriers for their pollen. As well, we might ask what the outcomes are when a plant species ties its reproductive fortunes to a bird, rather than an insect.

My project employs custom cameras designed for motion-capture data capture of insect visitors to flowers, in order to demonstrate contrasting bird versus insect visitation in pairs of closely related native shrubs. Fine-scale population genetic analysis in these plants is revealing evidence for systemic differences in the movement of pollen under these different pollinator regimes.

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Styphelia stomarrhena is pollinated exclusively by birds.

The video below shows bird visitation by a number of honeyeater species, as well as the way in which floral morphology excludes bee pollinators from accessing pollen or nectar in Styphelia stomarrhena.

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Styphelia xerophylla is the sister species to S. stomarrhena and has evolved a tight relationship with a single species of native bee: Leioproctus macmillanii.

 

The videos below show motion-captured footage of the native pollinator of Styphelia xerophyllum, a female native bee (Leioproctus macmillani).

However the flowers are also visited by introduced honeybees (Apis mellifera).

 

A quick note on plant names: These species recently underwent taxonomic revision, moving them from genus Astroloma to Styphelia. It is rather new, hence the confusion over these shrubs apparently having two names.

Photos from the field: The Great Western Woodlands.

The Great Western Woodlands (GWW) form the largest tracts of temperate woodlands left on Earth. They hold approximately 30% of Australia’s Eucalypt species, and close to 20% of Australia’s plant species overall. This is truly an overlooked gem of Australian biodiversity. Last Spring I was lucky enough to visit for my work on pollination in our native plants.

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My target there was Eremophila, a genus of approximately 250 species largely confined to arid and semi-arid Australia. The GWW represents one of the centres of diversity for the genus, and so I chose it as a likely spot to set up a new study contrasting bird and insect pollination.

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Eremophila alternifolia was one of about 15 Eremophilas I saw flowering despite the drier than average conditions.

I was joined by perhaps the best kind of field assistant: a trained and accomplished professional ecologist who also happens to be my beautiful wife. After driving 2800km from Melbourne to field sites near Norseman, Western Australia, we spent a little under two weeks observing pollinators, surveying and mapping populations of plants, and collecting samples for population genetics.

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One of the many viewpoints south of the Nullarbor Plain.

I left in awe of the scale of these woodlands, in love with the peace and isolation they offer, and a bit concerned over their insecure future. Fully 60% of the GWW is tenured “unallocated Crown land”, unmanaged and open access. With more visitors, and more appreciation of the value of these vast woodlands, I hope we can find a way to secure more of it into ongoing reserve for future generations.

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The bluebush understory contrasts dramatically with red sand in many areas. Front left is one of my study species Eremophila scoparia.

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The whole region is dotted with salt-pans.

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As predicted from the small, violet flowers, Eremophila scoparia was visited by a host of native bees.

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Eremophila decipiens has characteristic bird-adapted flowers.

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Camera traps being expertly arranged by Samantha. Footage revealed that E. decipiens was being visited by a range of honeyeater species.

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Eremophila calorhabdos

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This spectacular Grevillea hid a massive bloom of flowers underneath it

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The inflorescences are held on stems that grow along the ground underneath the shrub. The very long style with pollen-presenter is suggestive of adaptation to birds, but mammals might not be out of the question.

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Eucalyptus loxophleba with daggy botanist for scale

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Majestic Salmon gum (Eucalyptus salmonophloia) with Samantha for scale.

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The serenity of wandering amongst giant Salmon gums at dusk was magic.

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Gleaming bark on Eucalyptus salubris

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Elevating on Lake Cowan. Photo: S. Vertucci.

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For the second half of the trip I was joined by collaborator and all-round legend Dr. Renee Catullo. I made us walk 10km to collect camp gear following a single poor decision.

Stay tuned as research results emerge. The study should tell us about the way pollen moves under bee and bird pollination, and how those fine scale patterns play out on a grand landscape level.

The whimsical long-tongue fly and its favourite colour.

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The flowers on one of these plants conceal drops of sticky nectar. The other is a cheating orchid, presenting empty flowers and false promises. Can you tell which is which? Even if you knew which one carried nectar, how can you tell the difference between them? The two plants might look a bit different to human high-res optics, but now try blurring your eyes. Pretty similar, huh?

What about this pair?

Screenshot 2018-10-30 15.09.50If it’s difficult for our brains and eyes to discern the difference between the flower with the reward and the one that’s falsely advertising, then what hope does a nectar-hunting fly with low resolution compound eyes and a smear of a central nervous system have?

Specifically, I’m talking about this fly…

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If this fly looks embarrassed, its because it has orchid pollen stuck to its face.

Until now, you probably thought lion, or elephant, or rhino were the most impressive animals roaming the grasslands of southern Africa. Well you’re wrong, and it’s ok to change your mind after seeing the majestic long-proboscid fly of South Africa. There are several species of these magnificent beasts, and this one is named Prosoeca ganglbaueri.

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That giant proboscis hanging from its face is a tool crafted by evolution for sucking nectar from the bottom of long flower tubes, and it can grow as long as 5 cm (which is longer than the fly’s own body length). Unlike butterflies who coil their proboscises, the long-proboscid flies simply hinge the instrument down, tucking it away underneath their bodies to trail out behind them. And this species isn’t even the most extreme: proboscises in Moegistorhynchus longirostris get up to 8 cm!

Sometimes handling that long instrument can be a challenge…

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In some areas of South Africa, P. ganglbaueri is the only creature capable of extracting nectar from flowers with very long floral tubes, and because of this it has become the exclusive pollinator for 20 species of plant. Altogether, the long-proboscid flies as a group bear the great responsibility as the only pollinator for approximately 130 species of plant, making them a truly important creature for the ongoing survival of many South African plants.

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Figure 1 from Whitehead et al. (2018): Prosoeca ganglbaueri feeding from a variety of nectar sources. (a) Zaluzianskya microsiphon, (b) Scabiosa columbaria, (c) Agapanthus campanulatus, (d) Dianthus basuticus.

An interesting fact about flowers that are pollinated by long-proboscid flies, is that most of them are pink, or white, or some variation in between (with one blue exception). This strong colour preference is a critical feature directing the evolution of the cheating orchid flowers introduced earlier. For a deceptive orchid to attract this fly, the orchids’ flower colour must match the flies’ colour preference, or the mimicry simply won’t work.

In my recent paper, we asked whether the colour preference of flies was something that they learned, like we learn to associate that perfect golden-brown hue of fried food with a mouth-watering culinary experience, or if it was instead a more hardwired innate response, like a moth drawn to a lamp. The answer is important for understanding ultimately what is driving the evolution of false advertisement signals in mimic orchids. So, for example, if flies had an innate bias to pink or white, then cheating orchid flowers would evolve to match that bias, in the same way that any good advertisements are designed to appeal to the fundamental desires of its audience. On the other hand, if flies learned to associate nectar reward with certain colours, their preference should be determined by the colour of their local nectar diet. Under the learned scenario, orchids should be evolving to match local flowers’ colours, not any intrinsic bias of the fly.

To test this, I took advantage of just how easy it is to bamboozle these flies. With a home-made artificial flower, painted to match the pink and white flowers visited by the fly, anyone can fool a fly into attempting to feed. So I mounted a pink and a white model to my “interview stick”, and travelled across the rugged Drakensberg Mountains to interview various populations of flies. In each location, I recorded whether the local flies preferred probing the pink or white model flower, as well as the colour and species of flower that the flies were using for nectar there.


The results were clear. Flies used to feeding mainly on pink flowers preferred the pink model. Flies that fed mainly on white flowers preferred the white model. And flies that fed on both pink, white, and violet flowers, showed no clear preference between pink and white.

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Figure 3 from Whitehead et al (2018): Pink-white preference for flies at seven sites. The x-axis shows colour preference, with pink on the right, white on the left. Measured preference at seven sites is represented, with the colour of local nectar sources depicted in the small pie charts.

This tells us that the flies are very flexible in their preferences, and the strong implication is that these flies are learning to associate colour and reward. A further result showed that as the variation of colours flies fed from increased, this made them less choosy in the pink-white preference choice. So the bottom line is that the colour of their local nectar-buffet strongly controls a fly’s colour preference.

What does this mean for orchid cheats? Well, the colour of nectar cheats is all important, and what matters most for the success of a deceptive orchid is the colour composition of the surrounding nectar-rich floral community.

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Post-script:
Still wondering about which flowers in the opening images were cheats, and which had nectar?

In both cases the deceptive orchid is on the left. The first image features Disa nivea (left), and Zaluzianskya microsiphon (right), the second features Disa pulchra (left) and Watsonia lepida (right).

Reference:

Whitehead MR, Gaskett AC, Johnson SD. (in press) Floral community predicts pollinators’ color preference: implications for Batesian floral mimicry. Behavioral Ecology 

Plants and their very variable sex lives.

Plants mate. In a manner far more elegant than our own mammalian shenanigans, and far more important for the ongoing survival of the Earth’s ecosystems, plants are out there constantly having sex. And it is a deeply interesting thing involving insects, and wind, and stigmas, and stamens, and enough puzzling evolutionary biology to fill journal articles and occupy a small handful of academic careers.

My latest paper is about plant mating, and rather than wade through meadows of blooms to collect the data for this effort, I remained desk-bound in Milwaukee, wading through 30 years of plant mating literature with the intention of assembling a dataset to help us see plant mating in a new light.

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A mint-bush (Prostanthera lasianthos), caught in the act of mating.

As you may know, the flowers of many plant species are hermaphrodite, i.e. they bear both male and female sexual organs. This means plants can have sex with themselves. It’s called self-pollination, or “selfing”, and it can happen in two ways. First, pollen can move from the male parts of a flower to the female parts of the same flower. Second, on a single plant, pollen can move from the male parts of one flower to the female parts of a different flower.

“But isn’t this inbreeding??” I hear you ask, recoiling in horror at the moral and population genetic gutter down which I have so suddenly led you. Yes! Seed fertilized in a selfed flower is about as inbred as it gets, even more so than sibling mating. But you see, inbreeding is not always a bad thing—in fact inbreeding can actually be beneficial in some circumstances—and here’s where things get messy.

Genes are selfish. As such, they will do whatever it takes to get themselves propagated into another body. Consider then the selfish genes of a mother plant, which want to get into the next generation, and into as many individuals as possible. If a mother plant mates with a genetically different plant (an “outcross” mating event), its seeds each inherit approximately 50% of the mother’s genetic variation. This is because they combine with (and are diluted by) the genes of the pollen donor during pollination and sexual reproduction. On the other hand, if a mother self-fertilizes its own seeds, it transmits closer to 100% of its genetic legacy into each offspring. In the eyes of natural selection, this is a huge difference, and offers a great advantage to selfing over outcrossed reproduction.

So why aren’t all plants selfing all the time? This is because the huge advantage in transmitting genes via selfing is offset by the drawbacks of inbreeding. You can’t often get away with inbreeding without cost, and the cost is that inbred offspring are commonly less fit than their “outbred” siblings. Called “inbreeding depression”, this occurs because breeding from related individuals vastly raises the probability of combining rare genetic variants that harm the individual they are in. In the long run, inbreeding also reduces genetic variation that is essential for adapting to changing environments.

Evolutionary biologists have been pondering this tension for decades, and it led to the hypothesis that plants should be driven by natural selection into two polar opposite strategies: selfing plants should be favoured by natural selection when inbreeding depression is weak, and outcrossing plants should be favoured by natural selection when inbreeding depression is strong. Anything in the middle should not be adaptive, and should therefore be rare in nature. Sounds sensible, except numerous studies have now measured selfing/outcrossing across hundreds of plant species, and there is a curious and difficult-to-explain preponderance of plants that are neither exclusively selfing or outcrossing. These plants are having it both ways, seemingly hedging between strategies, and we call them the “mixed maters”.

Now for the problem my study addresses… Over the last 30 years, loads of studies have been measuring the selfing/outcrossing rate of plants in the wild. There have also been important studies which collect all these outcrossing estimates into big global datasets and generate observations like the one above: that mixed-mating is inexplicably common. For 30 years however, much of this discussion on global patterns was centred around average outcrossing per species, and using this to classify a species as a “selfer”, “outcrosser”, or “mixed mater”. We know evolution doesn’t work on a “species level” though. What is more appropriate is what is happening in a population context. And perhaps by averaging away all the variation within each species, my co-authors and I thought we might be missing an important perspective on the data.

What my co-authors and I did then was to collect all the outcrossing estimates from published papers containing three or more population outcrossing estimates. Going back 30 years, we collected data for 105 species and measured the variation in outcrossing within a species, among populations.

What we found was huge variation! There was commonly so much variation in mating within a species, that species averages felt inadequate for expressing where mating system variation lies. The data also showed that variation was difficult to predict. For example, there was an old hypothesis floating about that wind-pollinated plants were less variable in their outcrossing/selfing rate than animal pollinated species. The reason being that animals were thought to fluctuate more in their abundance and service between sites and seasons, while wind was a more consistent, reliable force for pollination. For the first time we were able to test this, and our analysis did not support the hypothesis. We also tested whether mating variation was evolving in a predictable fashion, but found that the relationship of plant species had no bearing on the variation we found in those species’ mating patterns.

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Arabis alpina: revealed in our study as a species with one of the most variable mating systems measured. By Hedwig Storch CC BY-SA 3.0, from Wikimedia Commons.

Ultimately, our study can’t solve the mystery of why we have so many mixed-mating plants. What it does do though is present a new way to look at the known range of variation in plant mating. There are other analyses waiting to be done with the data collected here, and we have highlighted where more studies are needed to answer interesting questions. For example, do different kinds of animal pollinators result in more or less variable outcrossing? Or do populations on the fringe of a species’ range experience more or less variable outcrossing?

As the body of knowledge on plant mating systems continues to grow, this dataset will grow too, and this population-level perspective on plant mating will hopefully provide the basis for the next insights into evolution’s influence on plant mating.

 

Full reference:

Whitehead MR, Lanfear R, Mitchell RJ, Karron JD. (2018) Plant mating systems often vary widely among populations. Frontiers in Ecology and Evolution, 6:38.

Further reading:

Goodwillie C, Kalisz S, Eckert CG. (2005) The evolutionary enigma of mixed mating systems in plants: occurrence, theoretical explanations, and empirical evidence. Annu. Rev. Ecol. Evol. Syst., 36:47-79.

Schemske, DW and Lande, R. (1985) The evolution of self‐fertilization and inbreeding depression in plants. II. Empirical observations. Evolution, 39:41-52.

Barrett, SC and Harder, LD. (2017) The Ecology of Mating and Its Evolutionary Consequences in Seed Plants. Annual Review of Ecology, Evolution, and Systematics, 48:135-157.

First video of bird pollination in Astroloma stomarrhena

I’m thrilled to share this never-before seen sequence of birds feeding on Astroloma stomarrhena, a winter-flowering shrub endemic to Western Australia.

Earlier this year, I decided A. stomarrhena looked like a perfect candidate for my new study on pollinators and gene flow. What I needed was a bird-pollinated species of plant, closely related to an insect-pollinated species. This one seemed to match all the criteria I needed, except there was no evidence that it was bird-pollinated. But with those long, tapered corolla tubes, and that pink-red coloration, I believed that birds absolutely had to be the pollinator.

The danger was, that while birds might be visitors, the plant could be somewhat “generalized”, and also use insects. This is pretty common, especially in places like Australia where European Honeybees (Apis mellifera) have invaded ecosystems that evolved in their absence, and honeybees will visit absolutely everything whether the plants are adapted to bees or not.

By deploying a new camera-trapping method that I am developing to record insect visitation, I was able to gather several days of pollinator observations, despite some very bad weather. After initially being baffled as to what honeyeater might visit such a low ground-hugging shrub, I got my answer after day one, when I captured video of my new favourite bird: the Tawny-crowned Honeyeater (Gliciphila melanops) feeding on the flowers. Furthermore, the recordings of honeybee fly-bys are sufficient to rule them out as pollinators.

This little result is a win on two fronts: a successful trial of new pollinator-monitoring cameras, and vindication of predicting pollinators from flower morphology.

Click here for the full HD video.

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Unearthing diversity in fungal dark matter

To be born an orchid is a most unlikely thing. First your parents must be pollinated, which is difficult. Orchids are both rare, and rarely pollinated due to the bizarre and dishonest means by which they go about attracting pollinators. Added to that, orchids often rely on a single species of pollinator to do the job.

Let’s say, however, that your orchid parents do manage to achieve fertilization. Your orchid mother will produce many thousands of tiny dust-like seed, which will be jettisoned into the wind. Unlike most seeds, you have no maternal energy investment to power your germination and first days as a seedling. Instead, you must rely on blind luck to land you within reaching distance of a strand of soil fungus. This fungus is the wet nurse to bring you into the world, invading the seed coat and hooking the young orchid up to a network of fungal strands that pervade the soil. Tapping into this network provides you with the first sips of carbohydrate and nutrient you need in order to build your first green leaf and begin to stand on your own roots. But it is not enough to land near any fungus. Many orchid species require fungal partnership with a specific species of fungus for this to occur at all. Multiplied together, it is a wonder that orchids ever overcome these odds to propagate themselves into the next generation.

The southwest of Western Australia is rightly famous as a global biodiversity hotspot. The area is particularly rich in orchids, and the spider orchids (Caladenia) are some of the most impressive and diverse of the region’s main orchid groups. In 1967, University of Adelaide researcher John Warcup discovered in association with Caladenia a new genus of fungi. Today those fungi are called Serendipita, and although we have known of them for around 60 years, there have been less than a handful of species discovered and described.

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The spider orchid Caladenia arenicola was one of those sampled in the study

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White spider orchid (Caladenia splendens)

Ubiquitous yet invisible

Although related to mushrooms, Serendipita fungi have not been observed producing the conspicuous spore-bearing fruit bodies we usually use to find and identify them. This makes them largely invisible, and I have therefore never observed them in the wild. Despite that, recent research using DNA sequencing has found them to be absolutely everywhere. Inside all kinds of plants, outside all kinds of plants, and distributed from the equator to Antarctica. It is clear then that there must be a hidden biodiversity of these species siting, waiting to be discovered.

My study took a wide sample of southwest WA spider orchid samples and assayed them for the presence of Serendipita fungi. We then sequenced the DNA of all the fungi we found, and used a new analytical technique for dividing that DNA sequence diversity into units that are probably species. This is currently the only way to sensibly identify Serendipita fungi, as they all look completely alike and do not produce spores in the lab.

We found a total of eight species of Serendipita fungi, including the original species discovered by Warcup back in the 60s. These came from a total of 18 species of orchid. At some sites where we sampled multiple orchid species, we found six species of Serendipita, meaning that the fungi were as diverse as the orchids!

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Lying just below the soil horizon, that swollen, yellow stem bit is called the “collar”, and its where all spider orchids keep their fungus.

Untapped agricultural potential?

Although we have chosen to study these Serendipita in association with orchids, their wide host association has got other researchers interested in their role in plant health and application to agriculture. For example, Warcup’s species and one other have been used in experiments (and patent applications) showing inoculation with Serendipita results in profound benefits for the host plant, including:

  • Increased plant weight in maize, poplar, parsley, tobacco, barley, wheat, switchgrass and Arabidopsis
  • Enhanced grain yield in barley
  • Accelerated plant development in barley
  • Greater seed set, increased growth and faster flowering time in tobacco
  • Increased wheat yield in poor soils
  • Improved nutrient uptake in chickpea and lentil
  • Improved salinity tolerance in barley
  • Enhanced protection against root and stem pathogens in barley
  • Improved resistance to stem pathogens in tomato
  • Stronger defense response against mildew leaf pathogen in barley
  • Increased essential oil content in fennel and thyme
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Figure 7 from Ray and Craven (2016): Root growth in winter wheat in Serendipita vermifera inoculated plants (left) versus control (right)

These proven benefits make Serendipita a potentially powerful tool to enhance plant productivity and stress tolerance in crops. Furthermore, application of Serendipita fungi could be an organic alternative permitting growers to lower the application of unsustainable and ecologically harmful synthetic fertilizers. Our knowledge of plant-Serendipita associations in the wild suggests that these relationships are more prevalent in nutrient poor soils such as those in southwest WA. They are probably one factor that allows our plant diversity to thrive in such weathered, poor soils. This means that species of fungi that have evolved with the nutrient poor soils (like those discovered in this paper) might be untapped tools to enhance agriculture taking place in those very same soils.

 

(Erratum: This story was edited to replace the figure attributed to Ray and Craven (2016). The first image I used was one showing Arabidopsis capability for mycorrhizal association. Arabidopsis is typically thought to be a non-mycorrhizal plant, which is why this is interesting. The image however showed slower growth in the mycorrhizal treatment. A related Serendipita has been shown to enhance root growth in Arabidopsis however. I have now updated the post with a more appropriate image of root growth gains in wheat. Thanks to Pawel Waryszak (@PWaryszak) for pointing this out.)

 

My study:

Whitehead, M. R., Catullo, R. A., Ruibal, M., Dixon, K. W., Peakall, R., & Linde, C. C. (2017). Evaluating multilocus Bayesian species delimitation for discovery of cryptic mycorrhizal diversity. Fungal Ecology, 26, 74-84.

Further reading:

Weiß, M., Sýkorová, Z., Garnica, S., Riess, K., Martos, F., Krause, C., … & Redecker, D. (2011). Sebacinales everywhere: previously overlooked ubiquitous fungal endophytes. Plos one, 6(2), e16793.

Weiß, M., Waller, F., Zuccaro, A., & Selosse, M. A. (2016). Sebacinales–one thousand and one interactions with land plants. New Phytologist, 211(1), 20-40.

Ray, P., & Craven, K. D. (2016). Sebacinavermifera: a unique root symbiont with vast agronomic potential. World Journal of Microbiology and Biotechnology, 32(1), 16.

Bokati, D., & Craven, K. D. (2016). The cryptic Sebacinales: An obscure but ubiquitous group of root symbionts comes to light. Fungal Ecology, 22, 115-119.

Photos from the field: East Gippsland, Victoria

I recently began a brand new project with the University of Melbourne. The beginning of a new project is filled with equal parts excitement and trepidation—excitement at the novelty, the blank canvas, the potential, and trepidation at not wanting to put a foot wrong in critical early decisions that will affect the outcome of a career-defining opportunity.

Here the photos from a first foray into East Gippsland, surveying sites for bird-pollinated Prostanthera walteri.

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Mt. Elizabeth

 

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Snowy River National Park

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Prostanthera walteri

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Prostanthera hirtula

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McKillops Bridge

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The Snowy River

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The Snowy River

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Prostanthera walteri

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Snowy River National Park

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Gippsland waratah – Telopea oreades

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Floral diversity in Prostanthera

 

Australia’s sexual swindlers.

Seduction. Pollination. Deception.

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I recently wrote an article for Wildlife Australia about Australian sexually deceptive orchids, their evolutionary biology, and historical and current research about them. You can download and read the article here: PDF. Thanks to Carol Booth for her collaboration and editorial guidance.

The latest of Australia’s sexually deceptive orchids that I have seen (below) are Caleana major, the Flying Duck orchid (left), and a spider orchid Caladenia clavigera (right). Both were photographed last week in Brisbane Ranges NP, Victoria.

Flowering this year is one of the best seasons of recent times both east and west of the country. So if you’re in Australia, don’t miss the chance to get out bush and enjoy it.

Sex, Lies and Nectar: Evolutionary Biology as Written by Flowers

I spoke to the Canberra Skeptics group earlier this week, on a subject most near to my heart. The abstract appears below. It is my aim to soon turn elements of this into a video for online audiences.

In the eyes of evolution, finding a suitable mate for reproduction is one of the most critical stages in any organism’s life. The great majority of flowering plants have outsourced this essential service to animals, giving rise to a fascinating evolutionary dance between plants and pollinators.

Charles Darwin was the first to recognize that flowers were superb teachers of evolution. I will touch on his classic work and explain what we have since learned about remarkable flowers who smell like dung and death, flowers who attract insects with the false promise of sex and a fly with a ridiculously long tongue.

These and other awesome examples of floral evolution would surely have thrilled Darwin, and may even solve his “abominable mystery”: the rapid rise of the spectacular diversity of flowering plants.

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Male thynnid wasp gripping tightly to the lure of the hammer orchid (Drakaea glyptodon).