I have written about mimicry before, describing why most mimics are imperfect and how some mimics imitate not only the appearance of other animals but also their sounds and behaviour. Now, I need your help with an ambitious experiment to test theories about the evolution of mimicry. Most people know that there are harmless animals that have yellow and black stripes to look like stinging bees and wasps. But did you know that there are many thousands of such species, all with different degrees of “bee-ness” or “waspiness”? The new experiment is designed to compare 56 harmless hoverflies with 42 wasps and bees to measure how similar they are. That’s 2,352 unique comparisons! This information will allow us to test exciting new ideas about the evolution of mimicry. There’s only one catch…
This particular experiment will use the human brain as a processing tool and the power of the crowd to generate data. It’s a bit like “Strictly Come Mimicking” (or “Mimicking with the Stars“, if you’re in the US): you just need to rate how similar you think the two insects appear out of 10. I’d appreciate it greatly if you could take some time to run through the experiment below. Don’t do it thinking that there is an end, though – there are 2,352 combinations, remember, and the images are randomly paired on each screen! You can access the experiment here:
My goal is to reach 10 ratings of each pair of insects. That means a total of 23,520 ratings. I know this is a long shot, but that’s the aim, people! Please do share it far and wide! I’ll share regular updates on the blog as the ratings come in (however many or few there are!).
I blogged some time ago about a Cafe Scientifique talk I gave on the topic of “Avoiding Attack” (broadly mimicry and camouflage in animals). I stole the title of the talk wholesale from the excellent book of the same name written by former colleagues Mike Speed and Tom Sherratt along with Graeme Ruxton). After giving that talk, I was asked to contribute to the Leeds Festival of Science – a great initiative where University of Leeds staff engage local people (particularly schools) with their research through on-campus and external events. As part of that event this year I took part in the “schools roadshow” where researchers go out into schools to teach about their work. I thought I would post the resources that I used here with some notes so that teachers can make use of the materials that I produced. Everything here is released on a Creative Commons license (CC-BY 4.0).
For those of you not familiar with Cordyceps fungus, that’s the one that attacks insects (and other arthropods) by infecting and then spreading through the whole body. The result is something like what you see below:
Each one of those little growths is a “fruiting body” and that is where the fungus releases its spores in order to found new patches of fungus. The most famous of these kinds of fungi is perhaps Ophiocordyceps unilateralis, which infects ants and influences their behaviour. The fungus forces an ant to climb a blade of grass or a twig and then attach there until it dies. Meanwhile the fungus produces a series of fruiting bodies that release spores from the new vantage point – the height helps those spores to disperse a greater distance. Apparently fossilised plants from 50m years ago also bear the marks of these Cordyceps-related attachments by insects, suggesting that this is an old battle.
What we don’t know is the extent to which Cordyceps influences the behaviour of other hosts. I posted the image above because it is the first time that I have seen a dragonfly infected in this way. It would make more sense (to me, at least!) for Cordyceps infecting a dragonfly to make it fly upwards while the fruiting bodies are releasing spores to broadcast those offspring as far as possible. However, the only image I have seen is this one where the animal is firmly rooted to the perch.
If it was a parasite that affected dragonfly flight then it wouldn’t be the first. A few recent studies (e.g. Suhonen et al. 2010) have suggested that dragonflies infected with parasitic mites that cling to the outside of the animal result in greater movement. It has been suggested that this could be an attempt to get out of an area with a high parasite population – after all, that’s not a great place to raise your little dragonfly family. However, we think this response has evolved to help the host and not the parasite, which is the opposite to the response elicited by the manipulative Cordyceps.
Suhonen, J., Honkavaara, J., Rantala, M.J. (2010) Activation of the immune system promotes insect dispersal in the wild, Oecologia, 162 (3): 541-547.
If you are interested in doing a PhD but are struggling to find funding that fits your project or have been unsuccessful in applications to the funding schemes that are scattered around (e.g. the NERC DTP schemes that are interviewing at the moment) then don’t despair! There are always funny little pots of money that you can apply to. The University of Leeds has three such scholarships available that can be used to fund PhD research in biological sciences (and some other areas). These all close on 1st June but if you are interested in applying please do get in touch with me (or one of my colleagues in the Ecology and Evolution Research Group) to discuss a potential project. The sooner the better!Read More »
I’m delighted to announce a suite of additional PhD projects in the School of Biology at the University of Leeds (scheme details are here). These are in addition to the dozen or so competitively-funded projects through our NERC DTP, so please do check there as well if you are interested. Most titles are indicative of the broad research area, but there will usually be a great deal of flexibility in the nature of the project depending on the interests of the student. The deadline for all projects is Thursday 29th January 2015, and applicants will need to have submitted a research degree application form (see our “How to apply” page) and be in receipt of a student ID number prior to application for the scheme. Briefly, the titles are:
The Evolution of Plant Form
Marine microbial processes and interactions
Improving piglet survival and subsequent performance
Managing soil plant processes to enhance the sustainable intensification of agriculture
Emerging Infectious Diseases
Continental trends in, and drivers of, the spread of European aquatic invasive species
Biomimicry, biophilia, and urban design solutions
Identifying and investigating factors which improve sow performance in Irish pig herds
See the project summaries below for more details.Read More »
Something strange seems to be happening in one particular species of damselfly, the common blue jewel Rhinocypha perforata (pictured right). Or at least it has been caught on video for the first time… Aside from being a particularly attractive species of damselfly found in China, Thailand, Laos, Malaysia and Vietnam, the common blue jewel seems to adopt a rather unusual form of reproduction (for an insect, at least). Read More »
For the two or three people who actually pay any attention to what I get up to here, you might have noticed a bit of a theme over the past couple of months: large numbers of posts (an anomaly in itself!) summarising some of my papers. I set myself the task of writing these lay summaries to try to make my work a little bit more accessible to people who might be interested in the topic but who might not have access to the paper, have the technical skills needed to interpret the findings, or who simply don’t have time to go and read a 7,000 word scientific article.
I’m pleased to say that I am (nearly) up to date now, and you can see the fruit of my labour here or click the green links labelled “lay summary” next to each of my papers on my publications page. There are 30 summaries in total, with a couple missing for the most recent papers. Trying to make research more open and accessible is a personal passion, and so I’d love to hear what you thought of this. Is it useful? Is anything still unclear? Drop a note in the comments and let me know.
Background: Body size is among the most important characteristics of animals and plants. Larger animals are capable of buffering against their environment (think big polar bear vs tiny chihuahua in the snow!) so that they can survive in a wider range of locations, are capable of eating a wider range of prey, and consume more prey than smaller animals leading to a stronger impact on ecosystems. However, we are still trying to understand the factors that influence body size, both ecologically and evolutionarily.
What I did: A number of previous studies have compared body size in particular animals across different locations to see whether or not there are consistent patterns in that variability. I wanted to collect specimens of a single species (the ebony jewelwing damselfly, Calopteryx maculata) for analysis from across its entire range in North America, but the range is so large (Florida to Ontario, and New York to Nebraska) that I wouldn’t have been able to travel to sufficient sites within the one season that I have available. Instead, I asked a lot of local dragonfly enthusiasts to catch and send me specimens from their local sites. I am extremely grateful to all of them for helping, as this could not have been done without their kind volunteering of time and energy. I ended up with a substantial dataset of animals from 49 sites across the range. I showed that there was a general increase in size further north, but that this was not a simple increase. Instead, there was a U-shaped relationship between latitude and size with larger animals in the south and the north with an intermediate size in the middle. When I looked at the drivers of this trend, it appeared that warm temperatures resulted in higher body sizes in the south. In the north, the animals use shortening days as a signal to accelerate their development and so in the most northern regions animals were developing very quickly despite the cold.
Importance: Large scale (across the whole of an animal’s range) measurements of body size are essential to provide an ecologically relevant test of explanations for changing body size. These findings support previous laboratory work which suggested a twinned role for temperature and photoperiod in driving development in damselflies.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Time stress and temperature explain continental variation in damselfly body size”, was published in the journal Ecography in 2013. You can find this paper at the publisher’s website or for free at Figshare.
Background: As well as publishing in ecology and evolutionary biology, I am also interested in how that publishing industry works. There is a clear need to disseminate information as widely as possible in order to accelerate the rate of testing of new theories and discovery of new information. However, some publishing models (and some publishing companies) hide scientific research away so that most people do not have access to that work. Self-archiving is a way for researchers to make available certain forms of their research without breaking copyright (which is almost always handed over to the publishers).
What I did: I reviewed some of the literature on the benefits of self-archiving, in terms of the access to the general public and what has become known as the “open access advantage”: papers that are more openly available are cited more. I also show that over half of all ecology and evolution papers could have been archived in a format that was almost identical to their final, finished format without breaking copyright. I then highlight key methods that researchers can use to self-archive their work: publishing through institutional repositories, third party websites, or self-creation of online portfolios using online tools.
Importance: Self-archiving has the potential to open up research (often funded by taxpayers) to a far wider audience, and this is an important step towards making research more accessible to the general public.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled ““Going green”: self-archiving as a means for dissemination of research output in ecology and evolution”, was published in the journal Ideas in Ecology and Evolution in 2013. You can find this paper for free at the publisher.
Background: A large number of species are expanding their ranges in response to climate change. This is also true in the damselflies, where the small red-eyed damselfly (Erythromma viridulum) has recently (around 1998) crossed the sea from France to England. Since then, the species has moved hundreds of kilometres north in an unprecedented range expansion (at least as far as European dragonflies and damselflies are concerned). What is less clear is what impact this expansion has had on the species. Are the newly-founded populations the same as those that are resident in France? Can we trace the arrival and expansion of the species through genetic techniques?
What we did: Simon Keat was a PhD student at the University of Liverpool who was lucky enough to be just beginning his PhD when the small red-eyed damselfly first established in the UK. Simon surveyed a number of populations around Europe and in the UK, collecting animals to measure them and extract DNA. With the body size measurements we showed that animals tend to show a strong relationship with latitude: populations further north were much larger and this held for both the older populations in France, Belgium and Germany as well as the newer populations in the UK. Looking at the genetics, we had expected to see declining genetic diversity further north, as a small number of individuals led the charge up the country. However, instead of a decline in diversity in the UK we saw an almost complete lack of genetic pattern. This suggests that the animals were moving in such great numbers that there was not the time for any local patterns to develop.
Importance: Range expansions have important consequences for many aspects of human life: agricultural pests shift and threaten crops, diseases and their vectors shift and threaten human health, and endangered species shift and potentially move out of protected areas. We have shown that during this particular range expansion there has been negligible change in genetic structure but that newly-invaded areas contain relatively large damselflies. Since damselflies are voracious predators, this could have substantial implications of local ecosystems.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Bergmann’s rule is maintained during a rapid range expansion in a damselfly”, was published in the journal Global Change Biology in 2014. You can find this paper at the publisher or archived at figshare.