To bee or not to bee – why some insects pretend to be dangerous

I just had my first article published at the Conversation – an excellent online collaboration between journalists and academics. As part of their publishing model, anybody can share any articles. So here’s mine!

To bee or not to bee – why some insects pretend to be dangerous

Christopher Hassall, University of Leeds

In the summer of 2011, panic gripped a small community in Gatineau, Quebec. Hundreds of small, striped insects were buzzing around a children’s playground. The playground was evacuated and entomologists were called in to establish whether or not the animals were dangerous. The answer was no, but it is easy to see why local residents were concerned. The animals that had taken up residence in the playground were hoverflies, a family of harmless fly species that have built up quite an arsenal of tricks to convince would-be predators that they are dangerous.

The panic that a swarm of hoverflies can generate belies the fact that they are immensely beneficial insects. Many of their larvae (the baby hoverflies that look like maggots) crawl around on plants feeding on the aphids that would otherwise eat our flowers and crops. Meanwhile the adults –- the stripy, flying insects that instil such terror –- spend their days pollinating flowers as they feed on nectar and pollen. But flying around in the open leaves hoverflies vulnerable to predators, a problem they have solved by evolving to resemble the stinging, pollinating insects such as bees and wasps with which they share the flowers.

Yet the story is not quite so simple. For every hoverfly that presents an exquisite example of mimicry (like the wonderful Spilomyia longicornis pictured above) there are several that really do not seem to be trying at all. Given that mimicry can obviously benefit hoverflies, why don’t they all evolve such excellent abilities?

Researchers found a potential solution to this Darwinian puzzle in 2012, when they looked into the characteristics of mimicking and non-mimicking hoverflies. You might expect that birds would prefer to eat larger species of hoverfly, since those hoverflies represent a bigger, more rewarding meal. Those larger species would therefore have more to gain from mimicry because they are under greater pressure from predators. Sure enough, it turns out that the colour patterns of the largest hoverflies (which are effectively flying buffets for birds) bear a close resemblance to the yellow, black, and white stripes of wasps and bees. The smallest species (which are barely worth chasing) do not show such similarity.

However, hoverflies have more than just wasp-like costumes. Some species also have considerable acting talents. It has been known for decades that certain hoverflies will pretend to sting when attacked, or hold their dark front legs in front of their heads to make it appear as though their antennae are long like those of wasps.

A recent extensive field survey showed that the species that behaved like wasps and bees were comparatively rare (just like the species that look like wasps and bees). This behavioural mimicry also tended to occur only in those species that already showed a strong visual resemblance to wasps and bees. In other words, those species that had the costumes also had the acting skills.

Insect sound bites

One of the most fascinating aspects of hoverfly mimicry has recently been dissected in great detail. As well as looking like wasps and bees, and acting like wasps and bees, some species also sound like wasps and bees. As part of our most recent project, my colleagues and I caught 172 insects from 13 species of hoverflies and nine species of wasps and bees, and brought them into a soundproofed recording studio. There, they recorded the sounds the insects made during regular flight and when the animal was attacked (simulated using a sharp poke with a pair of tweezers).

When they ran a statistical analysis on these sounds, the researchers found that some species of hoverfly make sounds when they are attacked that are indistinguishable from the high-pitched alarm buzz of bumble bees. The high-pitched buzz that bumble bees make seems to be produced by the bee unhooking its wings from the muscles that drive them, resulting in a completely different sound. This is a bit like what happens when you take your car out of gear and rev the engine – a lot of noise and you don’t go anywhere. It seems that hoverflies are capable of the same behaviour.

A board covered in ‘pastry prey’ used for experiments on wild bird predation.

But just because statistical analysis can’t tell the difference, that doesn’t mean natural predators can’t. To test for the benefits of this sound imitation in the wild, researchers presented pastry models of insects to wild birds with the different sounds. Pastry has approximately the same nutritional content as the insects that the birds forage on naturally, being part fat and part carbohydrate. The pastry can also be painstakingly painted to resemble insects as well, as in the photo to the right. To the surprise of the researchers, the birds only avoided the bee sounds. This was despite the fact that the hoverflies sounded identical to the computer-based analysis.

So we are left with a situation where an animal brain outperforms human researchers and their technical wizardry, which is not altogether surprising. Birds have evolved alongside a host of potential prey, developing the ability to find safe prey while avoiding animals that sting. While the hoverflies have a complex and fascinating suite of acting skills to dissuade would-be predators, they are still part of an evolutionary “arms race” where predators either keep up or starve.

The best part of this particular story is that it is possible to watch it unfold in your back garden. Next time you see or hear an animal that makes you reach instinctively for the rolled up newspaper, take a minute to check that it isn’t one of nature’s great actors.

The Conversation

Christopher Hassall, Lecturer in Animal Biology, University of Leeds

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

A hat-full of academic how-tos

Dipping in and out of the stream of tweets, there are always fascinating links to excellent resources for academics at all stages of their careers. I just spotted another, and thought it might be about time to aggregate some of these for posterity. Here’s the quick list (to which I will add if people suggest links), and details are below

  1. “How to find a postdoc”
  2. “How to get started with R”
  3. “How to use Github and RStudio”
  4. “How to use Github effectively”
  5. “How to respond to reviewers’ comments”
  6. “How to write a literature review”
  7. “How to help fight sexism in academia”
  8. “How to make your publications more accessible”
  9. “How to make your work reproducible”

Continue reading “A hat-full of academic how-tos”

Messing about in boats

I realise that this is the second eulogy that I have posted on the blog in the last couple of months (which is all the more striking due to the low frequency of posts), but there was one passing recently that I simply have to mark. I was devastated to hear that Professor Brian Moss died recently. You will find a number of obituaries written by people who are better qualified to comment on his scientific work, and who knew him better as a person. However, while I was not as close to him as some, I did have the honour and privilege of learning from him as an undergraduate, a postgraduate, a postdoc, and as junior faculty, and so I feel the need to share some of the affection and deep respect that I felt for Brian. There have been a number of leading academics who have influenced my work and career (Dave and Tom in particular) and without them I would not have the collaborations, publications, or career that I enjoy today. However, I think it’s fair to say that Brian had the single largest personal influence over me from anyone within the academy, and shaped the academic that I have become. Other people watch David Attenborough on television, but I had the privilege of being taught by and working alongside my very own Attenborough who inspired me to think in different ways across disciplines. Continue reading “Messing about in boats”

Why I am voting “Remain”

stronger-in-logoAs with a number of friends, I am growing increasingly concerned that the UK will vote for Brexit. My postal vote is already submitted, and I voted to remain. From our continued membership of the EU we gain human rights, environmental protection, workers’ rights, huge trade benefits, free movement, valuable immigration, a leading role in the governance of 500m people, and a place on the world stage. Specifically for my situation, I value the ability to work across borders as a researcher where I have the opportunity to learn from and work alongside academics across the continent. I am funded by an EU Fellowship which has brought cash back into the UK, am involved in EU grants which is bringing expertise and cash back into the UK, and am working to build international networks of researchers to solve major problems in sustainable urban development. Investors are pulling out of the UK for fear of Brexit, independent statistical bodies are advising of net loss if we leave, and thousands of valuable workers will be forced to go through long-winded (and currently unplanned) immigration processes to continue their contribution to our economy. Finally, this false notion of “taking back control” ignores the fact that one of our two legislative Houses is unelected, we remain an anachronistic constitutional monarchy, and only 25% of UK voters voted for the current Tory Government. To retain control, we need to stay a major player on the world stage and institute democratic reform within our borders. I’ve voted Remain, and I hope you will, too.

The Fishy Business of Brexit

fishing-boat-1281272_960_720Before you start to feel bad for the fishermen (fisherpeople?) on the Thames, here are some facts:

1) Quotas are important. If we fish all the fish, there are no more fish. The fishing industry has been utterly unable to regulate itself. EU quotas have led to the glacially slow recovery of managed stocks, because the quotas are higher than scientists advise. We need lower quotas combined with no-take zones, otherwise there will be no industry at all. Furthermore, UK quotas are divided among UK fishermen by the UK government so if one individual boat loses out it’s not necessarily the EU’s fault.

2) Three large companies own 61% of all fishing quotas. This isn’t about Michael Gove’s father alone on a tiny boat in a stormy sea. This is an industry monopolised by millionaires who are fighting regulation, just like all other industries. Viewed in that light it is completely unsurprising that “Big Fish” has joined Farage, alongside his banker allies.

3) Fishing rights to certain waters are set based on historic use. The fisheries industry does not want that to change because British boats are in loads of places that definitely aren’t British.

I know emotive stories about these poor Scots in their woolly jumpers and orange hats are relatable, but (as always) it is more complicated than that. It is completely understandable that they are unhappy: the history of their industry has generated a lot of jobs that simply cannot be supported through sustainable fisheries. It seems that the fishermen think Brexit would lead to higher quotas. Someday quotas might increase, but only if ecosystem-based management leads to increases in stocks that can support higher quotas, and that is the point of the EU Common Fisheries Policy.

The man who played with dinosaurs

We had some sad news in the department earlier in the week. We heard from his son that Professor R McNeill Alexander FRS had passed away at the age of 81. I didn’t know Neill very well, but we had chatted a few times over coffee in the department, which he still visited regularly until a year or two ago. We also lived in the same area of Leeds and I saw him often at the local farmers market. However, there was one particular encounter with Neill that I remember vividly, and I wanted to share the anecdote:

dinosaur-470161_960_720I was at a local Cafe Scientifique in 2013 when I saw Neill give a short presentation and demonstration of some of his world-leading research on dinosaur locomotion. However, rather than this being in front of an auditorium full of people (as would befit a Fellow of the Royal Society, former President of the Society for Experimental Biology, former President of the International Society for Vertebrate Morphologists, author of countless books and articles, the list goes on…), Neill gave an informal presentation to a group of four young children, their parents, and me. Sat in the cafe at Leeds Museum, Neill quietly explained to the small audience the history of his discoveries: how dinosaur models could be used to evaluate mass and centre of gravity, how dinosaur tracks could be used to infer gait, stride, and speed. I don’t recall him taking any personal credit, although it was his to claim, but rather he discussed the ideas as having been a communal advance. Then, at the end of the talk, Neill sat with the children and played with them using the same toys from which he had drawn such inspiration as a researcher and through which he had revolutionised so much of what we know about animal biomechanics and locomotion. I don’t know who the children were, and I don’t know whether they or their parents were aware that they were sat playing with dinosaurs alongside one of the greatest scientists of his generation, but for me that is perhaps the purest example of science communication that I have ever witnessed.

RIP Robert McNeill Alexander (1934-2016)

Keeping them engaged – tech solutions for in-class quizzes

clickerWhen I joined my current institution in 2012, I was offered the role of “Blended Learning Champion” – basically I had to promote a combination of the best pedagogical tools, including in-person techniques and digital technology. As soon as I started, I learned about what became known as “the clicker fiasco”. There was a time, you see, in the halcyon days of 2010/11, when all students in my faculty were given little devices that could be used to respond to questions during the class. It looked a little bit like the one on the right here, and worked extremely well. Lecturers would embed questions in their lectures, the students would answer using the clickers, and everybody was happy. At some stage some inconsistencies in the software versions, or possibly some old hardware (the exact cause is unknown), caused the whole system to come crashing down. What was frustrating about this situation is that there was substantial buy-in from academics to use these technological tools to enhance their pedagogical practice, but the failure of the clickers deprived them of both their favourite tools and their enthusiasm for blended learning. Now, I think I have found the solution: Socrative. Continue reading “Keeping them engaged – tech solutions for in-class quizzes”