Month: March 2019

Smart scientist studies smart butterflies

Posted on by jessica.camps

During his seminar on Monday, Dr Stephen Montgomery explained how his multi-disciplinary team tackles questions of cognitive adaptation, neuroecology and evolution in butterflies. Coming to us from the University of Cambridge, Dr Montgomery’s presentation was all the more interesting as he will be joining us in the School of Biological Sciences in September.

How does cognition relate to evolution?

This may seem like a daunting question, but Dr Montgomery has made it his career. Whilst initially working on primate brain evolution as part of his PhD, Dr Montgomery now leads a team of scientists studying ecological neurobiology in two clades of Neotropical butterflies, Ithomiini and Heliconiini. His research involves many collaborators and a range of experimental methods.

However, what Dr Montgomery described as “the main story” of his research concerns pollen feeding in Heliconius butterflies. The story begins in the 1970s when Larry Gilbert and colleagues pointed out that Heliconius butterflies were the only butterflies that collect and digest the pollen grains of Cucumis anguria. These pollen grains are the butterflies’ ‘elixir of life’, as they provide rare amino acids, which lead to greater longevity and halt senescence. However, whilst these plants are a reliable food source, they are very sparsely distributed. Gilbert thus concluded that Heliconius learned specific “trap-lines” to attain this food source. Later on, John Sivinski suggested that this enhanced ability for learning and memory is associated with an enlarged region of the insect brain, the mushroom bodies.

Dr Montgomery and his colleagues are now investigating the Heliconius mushroom bodies and their relationship to cognition and evolution.

The Montgomery team started with morphometric analyses of the Heliconius mushroom bodies and compared these to closely related Lepidoptera species. Although the data are not entirely collected yet, Dr Montgomery told us that the Heliconius mushroom bodies are “ridiculously bigger” than in other butterflies.

Whilst it is clear that Heliconius have enlarged mushroom bodies, Dr Montgomery wanted to know if this translated into different processing of sensory information. In an impressive feat of computer modelling, Dr Antoine Couto, a member of Dr Montgomery’s team, produced 3D models of Heliconius brains that suggest the presence of a relatively larger projection zone coming from the ventral lobula, which receives visual information. This would be consistent with the hypothesis that Heliconius learn these “trap-lines” with visual cues.

But Dr Montgomery was not content with a suggestion, he wished to confirm this with a large-scale behavioural experiment. Designing this experiment was challenging as Heliconius seem to only learn visual cues on a large spatial scale. Thus, Dr Montgomery and his team sought out ways to conduct comparative behavioural experiments.

This work is still ongoing, but Dr Montgomery already has pilot data coming from his PhD student Fletcher Young in Panama which explores whether enlarged mushroom bodies are associated with differences in learning performance. For example, Young is testing whether Heliconius can reverse an initial colour preference bias through conditioning training. Heliconius and other closely related butterfly species are being put through this training and after a certain amount of time, they can be assessed to test subjects had retained the information. Therefore enabling a test of whether or not enlarged mushroom bodies are associated with variation in learning and memory traits.

As previously mentioned, Dr Montgomery’s investigation of butterfly cognition is impressive by its scope of different approaches. As part of his team, Dr Francesco Cicconardi and Laura Hebberecht-Lopez are also investigating the developmental process of the Heliconius mushroom bodies. They will be undertaking a comparative developmental study of mushroom bodies across several species to identify the “turning point” which characterises Heliconius’ enhanced cognition.

The study will involve monitoring brain anatomy from larva to adult stages and analysing the corresponding transcriptomes.

Finally, Dr Montgomery expressed his wish to conclude this study by a functional characterisation of the candidate genes associated with the mushroom bodies, although he admitted that it might take them a few years until his team gets there. Nevertheless, his results so far are outstanding. I was particularly impressed with the scope of disciplines that his team unite to offer a solid and complete investigation of insect cognition, to an extent which I had never heard of before.

As usual, the seminar ended with some friendly drinks in our building’s Sky Lounge. Whilst overlooking Bristol on a sunny afternoon, Dr Montgomery expressed his excitement at the prospect of moving to our vibrant city and joining our just as vibrant academic team. I can say without a doubt that the sentiment is reciprocated.

Written by Violette Desarmeaux, Biology (MSci)

A dive into the world of dolphin communication

Posted on by jessica.camps

Dolphins are almost celebrities of the animal kingdom, globally adored for their intelligence, personality and aerial displays.

But to what extent do we know why they do what they do? Someone who tries to answer this question is Dr Stephanie King, one of the University of Bristol’s newest senior lecturers who has spent years studying these charismatic mammals. Those of us in this Monday’s seminar were treated to a fascinating look into what life is like studying bottlenose dolphin behaviour, and a sneak peak at Dr King’s new research which investigates the mechanisms behind how dolphins communicate, and the ways in which they can coordinate their behaviour.

Firstly, Dr King introduced us to the social structure of bottlenose dolphin communities.

Her research focuses on males, which congregate in groups called alliances, of either first (2-3 individuals) or second (4-14 individuals) orders. Alliances are aggregates of males, who form lifetime bonds with one another to coerce females into copulation with chosen members of the alliance. Associated behaviours have been analysed by Dr King and her colleagues during follows of the KS alliance, which habituates Shark Bay in West Australia. Currently made up of 7 males, each member can be confidently identified from characteristic nicks and cuts in the dorsal fin of each individual, acting almost like dolphin fingerprints. We were also told that alliance hierarchy is mysteriously complex: there is no linear dominance hierarchy; allied preference is not with kin; and that in fact age (mainly bonding in the juvenile period) can predict alliance formation. The adaptive value of these alliances is high, as male fitness (lifetime reproductive rate) is dependent on alliance formation and membership.

Throughout her talk, Dr King ensured the audience saw the dolphins in action, allowing us to understand and visualise exactly what the behaviours were that she was talking through.

This was done with the use of drone footage that accompanied the explanations, which included incredible birds-eye view shots of phenomenons such as the coordinated butterfly display. Other alliance behaviours explained by Dr King were those such as a ‘tangos‘ and petting.

Not only are visual behaviours important for the efficient functioning of the alliances, but so are acoustics.

‘Pop trains‘, like the name suggests, are a series of successive popping sounds which encourage females to come closer to the males. Dr King and colleagues wanted to know if these pop trains could be synchronised within the alliance. The adaptive value of this was discussed, one idea being that it could possibly encourage bonding through cooperation by promoting oxytocin release. Also posited was that highly synchronous pop trains could be a signal of a high-quality alliance.

Dr King gave the audience a first look at some unpublished research

While the ability of the dolphins to cooperate has been steadfastly proven, the question remains whether the dolphins actually understand what cooperation is; that is, do they understand that they need the exact role of their partner in doing certain tasks (Fig. 1)? Or are individuals actually responding to learned social and environmental cues? Dr King gave the audience a first look at some unpublished research that is pulling apart the possible mechanisms behind previous findings regarding these ideas. Dr King signed off the seminar with other suggested hypotheses for further study, such as whether personality influences cooperative partner choice. The seminar concluded with an animated Q&A and some lively debate, which without doubt continued afterwards in the Sky Lounge over lunch.

Figure 1: Photograph lifted from Jaakkola, Guarino, Donegan and King (2018). An aerial view of a cooperative task apparatus used to test dolphin understanding of cooperation.

 

 

 

 

 

 

 

 

 

Written by Esme Hedley, Biology (BSc) Year 2

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A Biography of Professor Jane Memmott

Posted on by dan.watts

“I’m still smiling!” was Professor Jane Memmott’s reply to being asked her feelings about becoming the newly-elected president of the British Ecological Society. In an office filled with shelves of books, a case of preserved butterflies, feathers from various species and a plant collection to rival the rest of the life sciences building, I interviewed Professor Jane Memmott on her career, interests and her journey towards the prestigious position she holds today.

Like so many of us, Jane’s lifelong fascination with nature began at an early age. It was during her childhood camping trips to County Clare in Ireland that Jane, inspired by her surroundings, developed an interest in ecology. In 1981, Jane began studying zoology at the University of Leeds. She described herself as a “keen and enthusiastic” student but mentioned that she still has “a horror of a few areas of biology from not liking them as a student!”. Jane went on to explain that it wasn’t until her third year at Leeds, when she really enjoyed everything she was studying, that she truly excelled as a student.

Professor Memmott took a year out after her BSc at Leeds, during which she took her first flight to Peru, where she worked as a tour guide in the Amazon rainforest for three months. This was Jane’s first taste of the tropics, and she became captivated by rainforests, leading her to write a PhD to be based in Costa Rica. Jane described one of her most memorable moments during her PhD in Costa Rica, when she encountered a sloth crossing the bridge of the field station. “They’re quite difficult things to catch- you can’t just unhook them from the handrail. We got it into a large dustbin and had the cutlery tray from the dishwasher over the top!” Once captured, the sloth was safely transported to a tree buttress to see what effect it would have on Jane’s experimental phlebotomine sandflies. Professor Memmott explained how she’d spent a lot of her life in tree buttresses, describing them as being “like a series of rooms around a big tropical tree.” The tropics can be a paradise for entomologists, and Jane recalled iridescent Morpho butterflies the size of dinner plates and giant damselflies that fly like helicopters.

“Jane described her endless fascination with understanding how the architecture of the network can affect pollination interactions and the robustness of the system to species loss.”

After her PhD in Costa Rica, Jane returned to the tropics for her first post doc. The project was to create the first food web to come out of the tropics, putting together a picture of the trophic interactions between the plants, leaf-miners and parasitoids of the rainforest community. This project got Jane hooked on studying ecological networks as a way of sampling whole communities. She explained, “rather than homing in on species x or species y, you kind of look at the whole alphabet at once.” Jane described her endless fascination with understanding how the architecture of the network can affect pollination interactions and the robustness of the system to species loss. Jane spent her second post doc working on the biological control of invasive plants. During this project, Jane spent time in New Zealand, which proved to be a contrast to the hot, sometimes gruelling nature of her project in Costa Rica. She spoke of her time in New Zealand, describing it as one of her favourite places in the world: “I lived a life of eternal summer – it was easy to live in a little house in paradise and travel round the country doing experiments.”

After ten years travelling the world and living out of a rucksack, Jane returned to the UK, where in 1996 she obtained her lectureship at Bristol. Jane stressed that returning to the UK did not mean forfeiting amazing wildlife encounters, mentioning the amazing views of peregrines that can liven up staff meetings in the sky lounge. From 2012 to 2016, she became Head of the School of Biological Sciences at the University of Bristol. This position came with some challenges, including leading the movement of the school to the new Life Sciences Building that we know and love today. Nowadays, one of her favourite parts of the job is teaching – especially first year lectures. Jane also enjoys seeing students from all around the world progress through university to do PhDs, and she loves to see the effect that the publishing of a big research paper can have on the young scientists leading the project.

 “I asked Jane what advice she would give to students interested in getting into academia. Her reply was “it’s absolutely worth it!”.”

Outside of her work, Jane enjoys gardening, dog walks and getting out and about in nature with her family; having recently been searching for short-eared owls on the Severn estuary. Professor Memmott describes herself as “always reading”- she enjoys novels, adventure books and books related to ecology. She also mentioned that her two teenagers take up a lot of her attention. I asked Jane what advice she would give to students interested in getting into academia. Her reply was “it’s absolutely worth it!”. She spoke of the “tremendous freedom” associated with being able to do your own research but warned to be prepared to put up with lots of rejection. “You can learn a lot from your rejections – it’s not wasted time.”

The British Ecological Society is the oldest ecological society in the world. The society has six journals including the Journal of Ecology and Ecology and Evolution, and it provides research grants and supports ecologists in their early careers. Jane joined the British Ecological Society as a PhD student and has been a member ever since. She described the society as having been very supportive over the years; providing her with a grant that enabled her to employ a field assistant to help carry out the field work that began all of her pollination research. I asked Jane what it meant to her to be elected as the president of the British Ecological society. She replied, “I’m very honoured – I’m still smiling!”.

Written by Jenny Stewart, MSci Zoology



From protists to whales: predicting the future of biological systems

Posted on by dan.watts

Complex biological systems are notoriously unpredictable, but forecasting their fate has arguably never been more important. In a recent seminar in the School of Biological Sciences, Dr. Chris Clements describes his latest research in this emerging field at the interface of ecology and conservation science.

The world is facing an unprecedented biodiversity crisis. As mankind’s ecological footprint grows ever larger, the rate of environmental change continues to accelerate. Identifying at-risk populations or ecosystems before they are irretrievably lost or damaged is becoming an increasingly important goal for conservationists, but predicting how complex biological systems will respond to evolving pressures is challenging.

One way of forecasting the future trajectory of biological systems is to use system-specific models founded on a detailed understanding of the underlying ecological processes. In practice however, scientists’ ability to do this is constrained by a scarcity of in-depth knowledge for the vast majority of ecosystems. An alternative strategy is to concentrate on inferring changes in the underlying state of the system from trends in more readily available data, such as estimates of population abundance. This approach is based on detecting statistical patterns or ‘early warning signals’, which can potentially be used to alert conservationists to the imminent danger of a sudden and catastrophic shift within an ecosystem, or the impending collapse of a population. A large part of Dr. Clements’ current research is focused on testing and extending these techniques.

“Under sustained pressure, the system will eventually reach a tipping point where it is so unstable that even tiny disruptions can trigger an abrupt change”

Dramatic shifts within ecosystems can occur when a change in conditions overwhelms the capacity of the system to return to its original state. Under sustained pressure, the system will eventually reach a tipping point where it is so unstable that even tiny disruptions can trigger an abrupt change. A classic example is the rapid transformation of pristine coral reefs due to declines in the abundance of algae-grazing marine life. While transitions to so-called ‘alternative stable states’ are often difficult to reverse, in theory, it should be possible to detect them in advance: as tipping points approach, predictable changes in statistical signals should become apparent.

Despite the potential usefulness of abundance-based early warning signals, the inherently noisy nature of population estimates can sometimes lead to unreliable predictions. Animals living in complex and inaccessible landscapes are usually elusive, and it can be tricky to estimate population sizes with confidence. One possible solution to this problem is to combine or replace abundance-based early warning signals with information on trends in key individual traits, such as body size, which can be estimated more reliably. Crucially, shifts in the distribution of body sizes within the population at-risk can be indicative of deteriorating environmental conditions, and of a population under strain.

“Dramatic shifts in the variability of body size also predicted plummeting worldwide populations of blue, fin, sei and sperm whales during the historical period of commercial whaling”

By describing his recent experiments on microcosm populations of the predatory protist Didinium nasutum, Chris showed that the collapse of stressed populations was preceded by a sharp decline in mean body size. Switching focus to an analysis of whale populations during the 20th century, Chris went on demonstrate how dramatic shifts in the variability of body size also predicted plummeting worldwide populations of blue, fin, sei and sperm whales during the historical period of commercial whaling. In both cases, trait-based early warning signals produced more accurate predictions about timing of population collapses, compared to those based on measures of abundance.

While our understanding of trait-based early warning signals is progressing rapidly, there is still much to learn about how these techniques can be applied to identify at-risk biological systems in the real world, where populations differ markedly in the rate of environmental change they are exposed to. Using both mathematical models and experimental microcosms, Chris’s research group is currently focused on tackling a range of unresolved questions in this area.

Written by Andrew Szopa-Comley, PhD student in Biological Sciences