With the simulated heatwaves experiments well under way, and the behavioural experiments finally progressing, we can breathe a sigh of relief. Since Sofia Gigliotti joined us in April 2022, we have been so busy preparing experiments, sourcing caterpillars and setting up the field study, that this is my first post in four months and Sofia has left us! However, it is a sign that we have been working very hard to make our British Ecological Society-funded large project work.
Jamie Smith has been in charge of looking after the Pieris brassicae pupae. He has released them in their field enclosure and they have mated, produced eggs and the caterpillars have successfully hatched. He has then set up the simulated heatwave experiments and is attempting cross-matings between heated individuals and controls. Fingers crossed it works out! Meanwhile Electra is investigating the behavioural thermoregulation of caterpillars. Originally we were hoping to use large white (P. brassicae) too, but we had to source some new ones when the first batch died - I do wonder whether our heated diapause caused them physiological stress (see for example, this new work by Nielsen et al 2022 on Pieris napi). Electra has worked against all odds as two more batches of caterpillars did not make it! She is now working with a third batch sourced from the wild, and things are finally looking better.
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A couple of weeks back I talked about my new venture as a member of a Special Topics Network on Thermal Fertility Limits. This is a network of researchers interested in delving deeper into the mechanisms behind fertility failure following heat stress. I attended the first of three online meetings of the network and, after so many months at home with little interaction from a research perspective, it was so interesting and refreshing. We discussed a range of ideas around the topic and, as you'd expect, we had more questions than answers. We started off by asking: what do me mean with fertility? Do we intend viable eggs and sperm? Number of hatched young? Clutches of eggs? Then we moved on to thermal stress. Heat stress comes in lots of different forms, which one should we study? Long-term heat stress or short intense bursts? Should we be looking at a constant temperature, steady or sudden increase? If an animal/plant suffers damage, should be looking at irreversible damage or measure time to recovery? Are there sex differences (some initial evidence suggests there are)? Does it matter at what developmental stage heat stress happens? For insects, which undergo metamorphosis, early stages are usually immobile and less likely to be able to buffer damage caused by heat stress. Could this affect the lifespan of the individual post sexual maturity? There seem to be almost endless possibilities for student research! If you are interested please do get in touch to discuss this exciting and timely topic. I will be writing more as the network develops, meanwhile we will stay in touch and meet regularly. At the beginning of this year, I was invited to join a Special Topics Network of colleagues (mainly, but not exclusively, behavioural ecologists) of the European Society for Evolutionary Biology to work on the evolutionary ecology of thermal fertility limits. The network is chaired by Claudia Fricke, Tom Prize, Rhonda Snook and Amanda Bretman, and I was very excited to join this initiative.
I have previously noted that males and females show different sensitivity to temperature stress. This may tell us something about how species will be affected by climate change and how we might buffer or tackle these sensitivities. I am very keen to explore this further. As I mentioned previously, I have been isolating at home for over half a year now, and therefore I was disappointed that I would not be able to join the inaugural meeting of the Special Topics Network set to take place at the end of March 2020 in Germany. However, due to the current lockdown in place in most of Europe and the rest of the world, the inaugural meeting was hosted online. Three separate online sessions were hosted to allow all participants to have a say on how the network should be shaped, and what we would like to achieve, so more to follow soon! In May 2019 I was lucky enough to visit the University of Jyväskylä (Finland) Darwin's group. This is a large research group headed by Johanna Mappes. I met Johanna last summer at the International Society for Behavioral Ecology congress, where she was giving one of the plenary lectures. Her lecture was fascinating. She described the work she and her collaborators had done on aposematism using the wood tiger moth, Parasemia plantaginis, as a model species. The work on colour morphs, the interaction with the environment and predators is really interesting, but the fact that Johanna has established various moth populations from different geographical locations in the lab, is what got me interested.
As you might have read from a previous post, I am looking at micropyle diversity - micropyles are small holes in insect eggs which allow the sperm to enter the egg and fertilise it. Micropyles vary a lot but little is known about this variation and I am trying to find out more with a combination of comparative analyses and experimental work. With the help of Sarah Aldridge, we visualised the wood tiger moth's micropyles clearly. I am hoping to investigate variation of micropyle numbers in the various moth populations that Johanna and her collaborators have established in the lab. So if you are a student, and this sounds interesting, please get in touch! And finally of pulla - this is a type of delicately sweet bread, usually in the shape of a bun, that Finnish people love eating alongside their coffee. Having lived in Finland for a couple of years with young children, I immediately got hooked and now it is a staple in our household. I find that baking and cooking are great ways to reliving memories! A few months back, I was working on a manuscript (soon to be published) about work I have been doing during my Back to Science Fellowship. We ran different experimental treatments for our Indian meal moth cultures, heating them during their development and up to the point when, as adults, they were ready to mate. We found that sperm got shorter the higher the temperature we subjected the insect cultures to. This is interesting in itself because it is important to know how species will be affected by rising temperatures as the climate is changing. However, as I was reading the literature, I was surprised to learn that this pattern wasn't unique. I mean, I have been working on reproduction since my PhD, so I have done a fair bit of reading on the topic in general and yet, I had not noticed this pattern before. Let me explain. It is well known that male mammals are unable to produce sperm at body temperature, hence the reason why mammalian testes are usually located outside the body cavity - there are some exceptions to this pattern, for example in marine mammals, but these species have developed adaptations to cool the testes. However, what I was reading in the literature, was that when subjected to heat stress, male mammals and some male insects too, become infertile - and this is the interesting part - before the females do. So, you can mate females who have also been heat stressed to non-stressed males - and they can produce offspring but the reverse doesn't work, heat-stressed males are infertile. Somehow, spermatogenesis (the production of sperm) - and more generally gametogenesis (the production of gametes) too, as plants show the same trend - appears more sensitive to heat stress than oogenesis (the production of eggs). Then, in January, an opinion article came out that summarised exactly what I had been thinking. As I read it excitedly, I noticed that the authors had not picked up on the male/female differences on heat-stress sensitivity, so I wrote a comment. It is not only intriguing that males and females show different sensitivity to temperature stress, it may also tell us something about how species will be affected by climate change and how we might buffer or tackle these sensitivities. I am very keen to explore this further. So if you are a student, and this sounds interesting, please contact me. In August I attended the International Society for Behavioral Ecology (ISBE) 18th congress in Minneapolis, Minnesota. It was one of the best conferences I have ever attended. Not just because of the great science I expect to find, but because this is one of the most child-friendly conferences in my field. There were fewer participants than usual, which meant I could interact with people more easily. The range of topics covered and the plenaries were inspiring - which is exactly what you want a conference to be. It was set in the beautiful and friendly city of Minneapolis. Above all though, ISBE provided free childcare and travel grants for early career researchers. As an early career researcher, part postdoc part lecturer, and with a young family (I have a brood of three), this is an amazing opportunity to present my work, meet colleagues and travel with my family. I submitted a poster and a travel grant and was lucky enough to secure both. As I started preparing my poster, the children were interested in what I was doing. It seemed fitting that they should prepare their posters too. And so they did. We went along to the conference with all posters rolled up in my tube (even managed to retrieve it after forgetting it during the security checks!) and the two eldest and I (the youngest wasn't so keen in preparing his), attended the poster session. Needless to say, their posters were far more popular than mine! The children loved the evening sharing their work with other conference participants, it was the highlight of our stay. After the conference, we took some time to explore the green and blue state of Minnesota, which is just about perfect for a family of nature addicts. Below is a selection of our favourite nature shots. If you ever get the chance, Minnesota is gorgeous. |
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