The Resilient Postdoc: How to be ok with uncertainty.

Posted on 25/09/2019 by michaelrwhitehead

Building resilience in the face of career anxiety…

One of my favourite plants.

In arid Southern Africa there exists a most fantastic species of cucumber. Like other cucumbers, its fleshy fruits are refreshingly high in water. Unlike just about any other flowering plant, these fruits develop beneath the ground, concealed and entombed by soil and sand. This bizarre trait gives the cucumber its scientific name: Cucumis humifructus, humi- referring to soil, fructus referring to fruit. To understand this deviant fruit, you must know who or what is responsible for fulfilling the purpose of this, or indeed any fruit: to promote the spread of its seeds. The only creature capable of finding and eating the fruit of Cucumis humifructus is one of our most fanciful and enigmatic mammals: the Aardvark. And this gives the plant its common name: the “Aardvark Cucumber“. In the context of seed dispersal, Cucumis humifructus is an extreme ecological specialist, having evolved to employ just a single species to eat its fruit and distribute its seed. The Aardvark itself is also an ecological specialist, its diet is composed exclusively of ants, plus the occasional Aardvark cucumber.

One of my favourite animals.

The Queensland Lungfish (Neoceratodus forsteri) is one of only a handful of extant lobe-finned fishes, having existed largely unchanged for over 100 million years—a time when the Cretaceous Empire of the Dinosaurs was at its ferocious zenith. The fish is remarkable for having the ability to breathe air via a rudimentary lung, which when combined with its fleshy limb-lobes, gives it the power to locomote and survive for days out of water. It is also the only fish with a soul (Figure 1). The age of first breeding for a lungfish female is 22 years. Read that again. 22 years! Lungfish development and reproduction is a longer and more drawn-out affair than our own spawning. You see, the lungfish is what ecologists would class as a K-selected organism, she grows slow, reproduces slow, and invests heavily in a few offspring. A temperate and upstanding lungfish will lay a few hundred eggs over her lifetime, while for contrast, the profligate and rapacious common carp can spawn 300,000 in a single season.

Figure 1: Cladogram for the vertebrates placing the evolutionary origin of the soul approximate to the divergence of the Actinopterygii.

The maladapted postdoc

So here I’ve described the extremities of two separate axes in ecological strategy. The generalist-specialist axis describes the narrowness with which certain organisms have adapted to specific niches in their environment. A generalist can tolerate a wide range of environmental variables, while specialists (Aardvark cucumbers) are exquisitely adapted to maximising the narrow case. The r- and K- selected life histories describe how organisms reproduce and grow, from boom-bust generations and mass dissemination of cheap offspring, to the heavy investment and delayed pay-off of fewer offspring, with better odds of survival for each one.

Academic science incentivizes production of K-selected specialists. Specialists are encouraged, and rewarded, because one has to specialise to not only reach the horizon of knowledge for a subject, but also to contribute to moving it back a meaningful amount. And academic scientists are K-selected. The gestation and development of a scientist is slow and long (4 years undergraduate and 3 years PhD at minimum), and the best outputs of academics take years to produce. It routinely takes years to get an original study from idea, to funded, to conducted, to published. It can routinely take a year to merely progress a paper from first submission to publication!

The problem with being a K-selected specialist however, is that they do very poorly in unpredictable and variable environments. The early career trajectory in research science is both highly unpredictable, and highly variable. With the scarcity of jobs, fixed term contracts lasting a maximum of three years and most frequently shorter, and low funding rates in grant schemes exacerbated for the young, those navigating this foggy career path frequently find themselves dealing with the anxiety of not knowing where or who they will be working with in the coming months. Add to that most support for ECRs drops off after five years, and its a direly unpredictable environment for a K-selected specialist to find itself in.
There are plenty of other careers that are similarly “contract-to-contract”. Freelancers, some Government roles, creatives, consultants, and so on. Compared to those careers though, academic success depends on the outcomes of projects borne of very long gestation periods (K- selected outputs). For a researcher, it can feel pointless developing new ideas, growing new collaborations, and applying for research funding if the funding outcomes are not known for nine months, and the money won’t be available for another six months—a future point for which they cannot forecast their own employment status. Therefore, many researchers must prepare to walk away every couple of years, a cycle that corrodes career momentum and mental health.

Learning to be ok with uncertainty

At the end of my first postdoc, I had a crisis. The end was steaming up and I had nothing to go to. While it’s a common feature of academic careers, no one knows how they will handle it until they get there. For many, it’s tough. The anxiety of the unknown can run riot through your life, dominating thoughts, detracting from focus at work, interrupting sleep, and sapping motivation—a cloud of noxious gas growing in saturation as the contract end date approaches.

I wasn’t totally surprised that it was hard to nail down another job straight away. What really caught me by surprise was how I responded to the uncertainty. Since I was a kid I had wanted to be a scientist, and now confronting the long-held idea that I may not be a professional biologist challenged a deeply held and largely unexamined part of my identity.

I was able to jump that chasm in 2015, and I’m on my third contract since that time. But I’m glad I went through that, because it forced me to face uncertainty, reflect, and adapt. I have learned to be ok with uncertainty, and today look at the possible future extinction of my research science career with much less emotion than I did four years ago. Not to say I don’t occasionally have bad days, but the days of amity now outweigh the days of anxiety.

The resilient postdoc

In case the time I have invested in wrestling this might return some interest for postgrad students and postdocs with the same worries, here’s some unsolicited advice on building resilience in the face of postdoc career anxiety.

Where are the exits? The most important and productive thing to do is prepare yourself for an exit before you need it. I have a whole post on this in the works. So for now, lie down on this couch and lets talk about our feelings.

Is your job your identity? This is both an asset and a liability. Academic careers reward those who let career conform the shape of their lives. Surrender to it and your platter of opportunities broadens. But hitching your identity to a job also makes you vulnerable when things aren’t working out at work. Finding meaning outside of work is a healthy strategy for taking pressure off career as a means to fulfillment. Think of it like an investment portfolio, spreading risk and associated reward. If your relationships, family, pets, hobbies, community work etc are thriving and fulfilling, you’ll be buffered against career anxiety.

Another sensible strategy is re-framing your identity around skills, rather than a role. The talents and skills you hone are more a part of you than the job title, however society more often places prestige on the title, not the skills.

Thinking about what else you could or should be doing is totally normal. Everyone is doing it, all the time. Most postdocs I talk to, many lecturers, most people in most jobs. I don’t know if this cognitive bias has a name, but it probably should. There’s no harm in occasionally fantasizing about the vineyard/cafe/photography/alpaca business you could go and open, but you’re probably falling victim to the focusing effect (see below).

Exiting academia won’t be your last move. There’s only so much momentum a publication record gives you to exit, re-enter and remain competitive. This increases the stakes on the decision to leave or not. However your first move out of academia need not be immune to revision. Release yourself from the pressure of finding the perfect job straight out of research. Trying new things is the only way to settle on what works for you, and in many ways researchers have been conditioned to avoid swapping and changing, because singular focus and narrow expertise is rewarded in academia.

Beware the grass-is-greener. Focusing on contract impermanence might lead you to think that other jobs with ongoing status are more desirable than they really are. This is the focusing effect, where we compare complex things along only one or two axes of variation. Plenty of people with ongoing jobs are unhappy and think your job looks marvelous because…

There are perks to this job. In science and academia we have the opportunity, at times, to make work a pleasure. Take advantage of that. If you’re not going to get to do this job forever, focus on the good things, don’t make it shit for yourself. Enjoy the moment.

The abyss is exciting. The end of a contract and unemployment can be seen as a career existential oubliette, or an exciting opportunity forcing your hand into taking a risk and trying some new things. Framing is powerful. Deliberately try to look at the same event from different angles.

Talking to colleagues can get tough. Don’t whinge, but never avoid communicating the facts. If you let your anxiety too often cloud your interactions with co-workers, you will find no one wants to get stuck in a conversation with you. When you need to talk, find the colleagues/mentors who you trust and can speak to in confidence, vent to family/friends, or speak to a counselor.

Stop looking sideways. People are going to get the jobs you want and missed out on. People are holding jobs you could probably do better than them. Dwelling on the number of people with your equivalent expertise who have found an ongoing role is demoralizing and unhelpful. It is also classic survivorship bias. It is easy to count the number of jobs that get filled by someone other than you, but much harder to count the number of failed job applications alongside yours.

If you’re feeling down, get off Twitter. Academics on Twitter are commonly whining or flexing, neither of which will make you feel better.

You won’t starve, life goes on. You’re a highly trained, intelligent individual with skills to offer. I cannot speak for all economies, but in Australia there are jobs everywhere for people like you. It’s also the case that for most of us, we return to baseline fairly quickly and adapt to what’s in front of us. The very worst outcome of a career change is highly unlikely to live up to the weight of anxiety the transition can create.

The whimsical long-tongue fly and its favourite colour.

Posted on 30/10/2018 by michaelrwhitehead

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?

If 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…

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.

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…

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.

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.

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.

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

Unearthing diversity in fungal dark matter

Posted on 27/02/2017 by michaelrwhitehead

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.

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

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!

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

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.

Pollination, evolution and an orchid’s seductive ruse.

Posted on 01/07/2014 by michaelrwhitehead

In a PR coup for dumpy little green orchids everywhere, research from my PhD recently landed on the cover of the journal Evolution. But what is it about?

Spring. The Blue Mountains, west of Sydney. Altitude 1000m. Frosty winds whip a swaying eucalypt canopy infiltrated by billowing cloud. Down below, amongst snowgrass tufts, rotting logs and bracken dwell the diminutive bird orchids. Genus: Chiloglottis. They huddle in tight colonies, sporadically sprayed by the high country squall.

Each plant holds two leaves pressed flat to the damp ground. Between the leaves a stem rises, holding aloft a single intricate flower in dusky shades of green and burgundy. When banks of cloud give way to azure sky and the shrike-thrushes resume their piping, these small blooms become irresistible lures.

Their target are the gracile flower wasps. Slim glossy black insects, zooming silently on shimmering wings. They are helplessly drawn to the flower. The bird orchid is emitting a scent, detectable only to wasps, which signals the promise of a mate. Known as ‘sexual deception’, the elaborate ruse uses a precise mimicry of female wasp pheromones to fool male wasps into pollinating the orchid.

However, here on the forest floor there is not only one species of orchid outwitting wasps for its own reproductive ends. Look closer and slight differences in the characteristics of flowers and visiting wasps betray something more complex and interesting. There are actually two species here, looking largely the same, growing in the same places, both deceiving their wasp pollinators through the false promise of sex.

By emitting subtle variations of their chemical trickery, these orchids have “tuned in” to two different pollinator species. This research paper explores this phenomenon as a way of separating the gene pools of closely related organisms. At the heart of it, the story here is about the forces that keep species apart once they split, or reproductive isolation.

First, we show that the different pheromones emitted by the two orchids are responsible for attracting different pollinators. Through arcane powers of chemical synthesis that I do not understand, chemists created synthetic orchid pheromones for us. We took these into the landscape and showed that the two chemicals attract two different wasps. The only perceivable difference between the wasps involved is yellow spangles on the carapace of one of the varieties. What’s more, this specific attraction is exclusive. Chemical A only attracts wasp A, and chemical B only appeals to wasp B.

Next, we take real flowers of both kinds and place them in a row and watch the hapless wasps roll in. We see that wasp A is only attracted to flower A, even when flower B is present just centimetres away. The results are identical to the results of the synthetic pheromone experiment.

On the basis of scent, we therefore expect that orchid A may never mate with orchid B. Exclusive attraction ensures that despite living amongst one another, some orchids may never exchange genes. Despite looking almost the same to us, they may as well exist on separate islands. They distinct separate species.

In order to back this up we then looked at the genetics of the species. By using the same kind of genes used in human DNA fingerprinting we were able to show that the two kinds of orchid exhibit differences in their gene pools of a degree expected if they were different species. Furthermore, analysis showed not a single individual displaying the genetics of a hybrid. Our last tests were to make hand-pollinated hybrids to check that hybrids could indeed form. These crosses showed hybrid offspring germinated and grew faster than pure crosses.

The potential for animals to drive the formation of plant species has long been recognized. This study gives us a strong case study of how that process might look. Our orchids are spectacular examples of the power of pollinators to create and maintain plant species. Through selective pollinator attraction, the orchids have been set upon unique and separate evolutionary journeys.

Roses reflect greatest above 620 nm, Violets reflect at 420 – 480 nm…

Posted on 13/02/2014 by michaelrwhitehead

Roses are red,
Violets are blue,
Botany is sexy,
But less so than you.

Along with odour, flower colour is perhaps the most important cue plants use to advertise to pollinators. Change the colour of a flower and that change can have large consequences on which pollinating animals are likely to visit^[1]. Bees, for example, are attracted to purple flowers with UV highlights. If that plant were to mutate to white, it could very well find itself being visited by nocturnal moths^[2].

In studying plant-pollinator evolution and ecology, it is very important then that we have some objective quantification of the colour of a flower. Human eyes are famously fallible and many insects and birds can see outside the range of our colour vision (400 – 700 nm).

The instrument we use is a spectrometer^[3]. It uses optic fibres to bounce an initially white-light beam off the surface you want to measure. The wavelengths of light that are reflected (as opposed to absorbed) determine the colour of the surface you are looking at. The spectrometer collects the reflected light, separates the wavelengths through diffraction and digitises the signal. The result is a graph such as the one above.

In the graph, the wavelength is given on the horizontal axis, while the proportion of reflectance is on the vertical. The rainbow bar above provides an approximation of how the human eye perceives a given wavelength of light. The rose therefore will reflect greatest at wavelengths above 620 nm, the red part of the spectrum. A violet most strongly reflects around 420 – 480 nm. A pure white surface would show high reflectance across the range of the visible light spectrum.

Dedicated to my sweetheart, who for the second year in a row has been alone on Valentine’s.

Kniphofia are red, Agapanthus are blue.

Fieldwork is fun, But I do miss you.

Michael Whitehead

Plants, pollination, evolution, ecology, natural history.

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