Science

Many plants rely on insects for pollination. While there’s an advantage to attracting generalist pollinators – the flower will get lots of visitors – limiting which insects can visit means it’s more likely that the plant will be pollinated by pollen from a different individual. One way of limiting visitors is with a nectar spur: a tubular outgrowth from the petal with nectar at the bottom. Only an insect with the correct length tongue will be able to collect the reward (and therefore will continue visiting the flowers). But how does the flower control the length and positioning of the spur? I’m now seeking to answer that question using toadflax (Linaria vulgaris) as a model organism, with genetic manipulation and transcriptomic analysis.

My PhD

The global population is currently around 7.5 billion, projected to rise to about 10 billion by 2050, so we’re going to need to find more food. Around 75% of the food we eat relies on insect pollination to some extent, and insect levels around the world are generally in decline. The increase in food requirements and the decrease in insect numbers don’t match up! Others are investigating how to reverse this decline; I looked at how to make flowers more attractive to insects (to help them find them faster) and more rewarding in terms of nectar and pollen (to help boost insect populations).

I did this by looking at the extent of variation in flower size and reward that exists in 21 varieties of strawberry. In practice this involved a month on a strawberry farm in King’s Lynn (by kind permission of Dr Paul Walpole). I then took that variation back to our bee lab to ask bumblebees questions about what they thought of that variation, and if they could use it. I did this with relatively simple testing: let’s say I wanted to see if bees could tell the difference between a round-outlined flower and a wiggly-outlined one. I put a reward (in the form of a droplet of sugary liquid) on the round ones and no reward (just a water droplet) on the wiggly ones, and watched to see if bees could learn to tell the difference. If they could, then I moved on to testing whether wiggly or round outlines helped bees move between flowers faster. And, of course, wiggliness of outline is just one of a whole host of characteristics available to test. The results of all this will be published soon.

I also looked at flower colour in a pink-flowered relative of the plant scientist’s workhorse Arabidopsis thaliana (a rather scrubby little weed which has white flowers), trying to find out what genes were turned on to make pink, and why those genes are turned off in Arabidopsis. In practice, this involved a lot of mixing of minute droplets of colourless liquids in the lab.

Additionaly, I’ve spent a long time staring at bees. What started as a six-week ‘get used to working with bees’ project grew into an interesting and absorbing piece of work watching bees vomit, which turned into a paper which was featured in the New York TimesThe Times, The Independent, the Daily Mail, ITV News, Sky News, The Naked Scientists on BBC Radio and Australia’s Radio National and more. I also made bees choose whether to forage from high-sugar slippery surfaces or low-sugar easy-to-access surfaces, which tells us how they make decisions about foraging. I’m very grateful to Dr Jonathan Pattrick for allowing me to collaborate on both these experiments – while relentless to perform, they’ve allowed us to come to exciting conclusions.

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