Time is a tyrant and, as I have write this, my summer Erasmus student, Teun de Jong, has almost finished his internship. I first met Teun in Wageningen, in February 2023, during my visiting fellowship to the lab of Nina Fatouros. Teun was fascinated by my work on thermal fertility sensitivity in the large white butterfly, Pieris brassicae, and the experimental set up that Jamie Smith had worked on during last summer 2022 for his MSc research (as a side note, congratulations to Jamie on securing a PhD at the University of Hull!). Luckily, he secured an Erasmus research internship to come work with me in Lincoln this summer 2023! Teun has worked very hard this summer to replicate Jamie's experiments heating wild pupae of the large white butterfly, and measuring the effects of heat on butterfly reproduction success and fitness. Teun arrived the last week in May 2023, and, in a happy coincidence, I had just received news that I had been funded by the Royal Society for an international exchange with Sylvain Pincebourde. Teun therefore, started trialling different thermal imaging cameras with Sylvain's help. Following this, Teun launched into rearing butterflies and plants, setting up experiments and troubleshooting the butterfly's lack of interest in mating! I have thoroughly enjoyed working with Teun, who is looking for a PhD. I can highly recommend him, he is hard working, dedicated, and I have no doubt he will find a suitable project to pursue and excel in.
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It all started with an email in late August 2022. I wrote to Nina Fatouros at Wageningen University and Research (WUR), to ask her for some images (SEMs) of Pieris brassicae eggs. Over a few brief email exchanges, we discovered that we both shared an interest on insect eggs, and that we could learn from each other's different angles (mine on the evolution of reproductive traits, Nina's on plant-insect interactions). Nina invited me to apply for a Visiting Scientist Fellowship at WUR and then fast forward to 30th January 2023, I found myself on a train crossing the Channel heading for Wageningen, the Netharlands. I spent four intense (and fun) weeks at the Biosystematics Group, WUR. Nina, her PhD student Liana Greenberg, and I, drafted some hypotheses on latitudinal and climatic gradients effects on eggs of populations of Pieris spp. Nina and Liana have collected Pieris napi from across Europe, from Wageningen to Spain. Nina also has two stable populations of Pieris rapae and brassicae, which she has kept in the lab for a number of generations. I then spent several days in the company of Marcel Giesbers, a very knowledgeable SEM technician, to image Pieris eggs using Cryo SEM, which was a lot of fun (oh, and talking of Dutch cheeses with Marcel...). I have learnt a lot about plant-insect interactions (and dusted off my two botany exams taken decades ago), started a collaboration with an amazing colleague, and visited the Netherlands for the first time! I was made to feel at home by every member of the Biosystematics group, and I am indebted to Nina, Klaas, Eric, Liana, Wilma, Marcel, Patrick, Jordy, and everyone else at WUR + WEES for inviting me to give a talk. I really hope to be able to come back 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 search of micropylesWhen I arrived at the University of Lincoln in 2015, I started a project on a topic I had not worked on before: micropyles. These intriguing structures found on insect eggs (but analogous structures are also found in ovules of seeds in plants and on the eggs of fishes, among other organisms), are the point of sperm entry. Literally micropyle (from the Greek mikro- pule) means small gate: what a wonderful word!
My model species was the Indian meal moth, Plodia interpunctella, which proved rather difficult because of the size of its eggs, about half a millimetre long, or about the size of a dot on this page! It followed a year and a half of trying to image Plodia's micropyles with a variety of imaging techniques, to no avail. Recently, however, I have started collaborating with Professor Johanna Mappes on her model species, the wood tiger moth, Arctia plantaginis, an aposematic moth with larger eggs. Thanks to new Alicona 3D imaging microscope, just installed at our department, Sarah Aldridge (also a new collaborator) has captured this amazing image of a micropylar plate on A. plantaginis. Enjoy. |
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