IMM11-GroupPhotoI’ve fallen a little behind on updates, so in a bid to get things back on track, here are a few highlights from the lab over the past year or so:

Firstly, congratulations to Mark Koschmieder for completing his Master thesis on sexual selection and the evolution of allometry (a theoretical project I supervised together with Matthias Galipaud) and to Max Edich for completing his Bachelor thesis on identifying seminal fluid transcripts in different Macrostomum species just before Christmas! Our DFG seminal fluid project is coming to an end this year, and we’re busily writing several things up, so hopefully much more on that theme to come…

Also just before Christmas, it was our great pleasure to host the 11th International Macrostomum Meeting here in the department. The weather could have been better (as you can see from the group photo), but it was great fun having everyone here for our annual get-together of the Macrostomum research community for a weekend of talking worms.

I seemed to have missed writing about a few publications during the year too:

First, the special issue of Molecular Reproduction & Development dedicated to sex in hermaphrodites came out. My review focussed on flatworms, with other contributions from Stefan Siebert and Celina Juliano on cnidarians, Joris Koene on snails, Ronald Ellis on nematodes, Delany Rodriguez, Susannah Kassmer and Anthony De Tomaso on ascidians, Hui Liu, Erica Todd, Mark Lokman, Melissa Lamm, John Godwin and Neil Gemmell on fish, and a general introductory essay by Lukas Schärer. Thanks to Mariana Wolfner and Julian Wong for putting it all together!

Then in the spring, it was great to see Maike Foraita‘s Master thesis work published on strategic investment in sperm removal behaviour in the bushcricket Metaplastes ornatus. Maike and co-author Sophie Lehfeldt were students on our Master programme Behaviour: From Neural Mechanisms to Evolution, and conducted the experiments for this paper during our annual field trip to Greece.

Over the summer, a long-running project came to fruition with the publication of this paper in Biological Reviews, which is a sort-of review-theory-hybrid exploring the varying patterns of reproductive investment (as captured by gonado-somatic index, or GSI) among male and female broadcast spawning marine invertebrates. Geoff Parker was the driving force behind the study, with sterling contributions also from Jono Henshaw and Jussi Lehtonen. The four of us never met together in one place throughout the whole process (and with Jono and Jussi based in Australia part of the time, we were frequently working in very different time zones), but pinging emails and drafts backwards and forwards somehow worked very smoothly. To summarise the findings: broadcast spawners show a range of different sex-specific GSI investment patterns, with usually females investing more than males, but sometimes the opposite (or roughly equal investment is quite common too). Theoretically, we explored how factors such as sperm competition, sperm limitation and trade-offs with somatic maintenance and growth might affect GSI investment; greater female investment is easy to derive, but only under quite restrictive conditions would we predict greater male investment, so this empirical pattern remains something of an evolutionary puzzle. You can read the paper here, just don’t be too daunted by the ridiculously long (34 pages!) tables of raw data that interrupt the flow a little in the middle of the literature survey…keep reading/scrolling to get to the theory part!

And on a much smaller scale, it was also fun to write this Perspective with Leif Engqvist on an interesting study by Manser et al. on how multiple mating by female mice can keep a selfish genetic element in check.

2018 promises to be a bumper year for thesis and manuscript submissions, so there’ll hopefully be more to report here very soon…



One of the main reasons I began working on Macrostomum flatworms is because they are so plastic, dynamically adjusting investment into reproductive traits according to the prevailing social environment. However, we’ve recently discovered that one species we’re keeping in the lab, Macrostomum pusillum, isn’t really plastic at all. That was initially puzzling, but we now think it’s for a very good reason. Rather than preferring to outcross like its close relatives, our recent experiments would seem to suggest that M. pusillum individuals instead prefer to self-fertilise their eggs with their own sperm. That means they don’t really have to plastically respond to their social environment, because that social environment isn’t particularly relevant to how they gain fitness.

Having the option to self is one major advantage of being a hermaphrodite, of course. Even so, it is not straightforward that selfing should evolve, because selfed offspring are often less fit, suffering from inbreeding depression. By forcing worms to self or giving them the option to outcross, we found no evidence for differential inbreeding depression (suggesting the worms may not be outcrossing even when they have the chance), nor did we find any evidence for plasticity in the age that worms begin producing hatchlings, their relative investment in making sperm versus making eggs, or the speed at which sperm are produced (all of which we would have expected under preferred outcrossing, based on what we know from other Macrostomum species). The next step will be to perform direct genetic tests for selfing, but for now our new working hypothesis is that the amazing diversity in Macrostomum sexual biology extends to a novel dimension, namely that some worms prefer to mate with another individual in order to reproduce, whereas others prefer to do it all by themselves.

Congratulations to lab member Athina Giannakara, who performed the study. The paper has just been published in the Journal of Experimental Biology here. (JEB were kind enough to feature my recent work on a hypodermically self-inseminating relative of M. pusillum, so the journal felt like a natural choice.)

Giannakara A, Ramm SA. 2017.
Self-fertilization, sex allocation and spermatogenesis kinetics
in the hypodermically-inseminating flatworm Macrostomum pusillum
Journal of Experimental Biology, doi: 10.1242/jeb.149682


Photo credit: Athina Giannakara


At the author’s urging, I just began composing a review of Stephen Heard’s brilliant new book The Scientist’s Guide to Writing. It got me thinking about where it fits in the science writing ecosystem. So, rather than a review of just that book, this turns out to be a comparison of my favourite three books on the topic. Which of three you’ll benefit from reading the most depends I think on your level of prior experience…

For advanced undergrads and early postgrads learning the nuts and bolts of a how a scientific paper is put together, in a crowded field I particularly like:

Writing Scientific Research Articles: Strategy & Steps
by Margaret Cargill & Patrick O’Connor
2nd edition, 2013, Wiley-Blackwell

The book has clearly been assembled with the beginning researcher in mind, and perhaps especially the non-native English speaker. It is very well suited to both individual study and for use in a teaching context. Each chapter takes a section of a research article (introduction, methods, results etc.), or a part of the process of writing a research article (submission, peer review, responding to reviewers…), providing both essential background information as well as suggesting strategies and exercises to develop the relevant skills. It’s a very practical approach, with an emphasis throughout on learning about these different aspects by analysing real, published examples in the reader’s own field.

[Aside: For German speakers, a special mention here for my colleague Nils Cordes’ new book also pitched at (biology) undergrads: Schreiben im Biologiestudium (2016, UTB).]

For PhD students who already have some experience with writing and with reading the scientific literature, but who now need to learn the craft of turning their own data into papers that effectively communicate their findings to others, I would throughly recommend Heard’s book:

The Scientist’s Guide to Writing:
How to Write More Easily and Effectively Throughout Your Scientific Career
by Stephen B. Heard
2016, Princeton University Press

The tone of the book is much more conversational. Rather than laying down just ‘the facts’ as clearly as possible, one instead gets the impression of someone’s experiences being shared; of accumulated wisdom being imparted. There are many more personal anecdotes and diverting asides, especially on the historical development of scientific writing and the etiquette of publishing. I liked those elements, but to an absolute beginner, I can see how they might actually hinder the uptake of the main messages. Overall, though, I think the balance is just right for a PhD student, which is of course a crucial niche. There’s enough of the basics to make sure everything is covered, but plenty of “professional advice” beyond the strict focus on the actual writing itself. I particularly liked the early chapters on learning to become a professional writer, developing strategies and processes to help get into the writing habit. Not everyone will come to the same solution, but Heard does a good job of making you think about the importance of writing to a scientific career and on the practical steps one might take to become better at it.

Finally, for postdocs and more experienced writers looking to hone their writing skills, my last recommendation would be:

Writing Science:
How to Write Papers That Get Cited and Proposals That Get Funded
by Joshua Schimel
2012, Oxford University Press

Here the focus is more squarely on the actual words on the page; how the language we use and the way we structure it affects the clarity and force of the story we want to tell. It’s definitely not for beginners, and doesn’t claim to be. Rather, what Schimel achieves I think better than any other book I’ve read on writing is to make the reader really think (or re-think) about the fundamental goal of any piece of (scientific) writing, and – by analysing many real examples – to learn to pay close attention to how language choices really matter. Early in the book he introduces the key concept of making a story ‘sticky’ (an idea he borrows from Heath & Heath’s book Made to Stick). Now, that might sound a bit like marketing, and that might make some readers uneasy – surely the aims of marketing and science are diametrically opposed ? – but I think he convincingly argues that the concept of stickiness transcends the details of how one might use stickiness to, say, get more customers to buy your products, or to sell more newspapers, or whatever, and speaks to a larger truth about how we can argue and convince each other by using all the linguistic tools available to us. It’s just that historically marketing people or journalists have done a better job of using those tools than have scientists (a situation Schimel aims to correct).

Looking back, I think the book titles reflect these differing target audiences quite well. For Cargill and O’Connor, the focus is on the scientific research article, dissecting it up into its component parts in order to understand what exactly it is and how one might assemble one. For Heard, the focus is rather on the individual scientist, learning the craft of writing as part of the daily routine of actually being a professional researcher tasked with regularly producing scientific articles. For Schimel, the science itself takes centre stage: how do we come to gain new insights from writing about our research, and how can we most effectively convey those to others?

Phrased like that, there’s a natural progression from one book to the next, and correspondingly, I think I gained most personally from reading Schimel (which likely just reflects my own career stage). Not least among the insights in Writing Science was that, although research articles are full of strange conventions and unwritten rules, it’s worth always remembering that there’s nothing particularly special about their underlying aim: to locate the story and tell it effectively. Reading Schimel will help you do that. Heard’s book was packed with insights too, and could certainly profitably be read by more experienced researchers looking to improve their writing and perhaps especially their writing routines; I will be enthusiastically recommending it to all of my students from now on, with Schimel a perfect complement once they have mastered the basics.


Photo credit: Thomas Lefebvre, via Unsplash.

2016-06-11 18.53.54

Just emerging from a busy teaching period, it was as ever a pleasure this year to welcome first another enthusiastic group of Bachelor students to our upper-level undergraduate course on “Key Concepts in Evolutionary Ecology”, followed by another excellent set of Master students taking our module “Evolution of Behaviour”. The Master module – which Klaus Reinhold and I teach together – focuses on bushcricket behavioural ecology, and our aim is to try to pack in the full scientific “experience”, from developing a hypothesis and designing an experiment to test it, then actually conducting the experiment and analysing the results, through to finally presenting the research in a paper and oral presentation (all in 6 weeks!). The highlight is a two-week trip to central Greece, where we conduct the experiments the students have designed in the field. It was a brilliant trip this year, undoubtedly enhanced through various guest researchers joining us (thanks all!). Today is the last day of the module, and I’m very much looking forward to the students’ presentations of their work in the final symposium this afternoon.

A few other recent lab developments:

First, a very warm, if slightly belated, welcome to Ekin Demir, an intern student studying in Ankara who is joining the lab over the summer. During her visit, Ekin will work together with Bahar, myself and our collaboration partner Claudia Fricke in Münster on a spermatogenesis project.

Second, speaking of Münster, the lab was well represented at the Insect Reproductive Molecules meeting there this week. Well done to Bahar, Michael, Yumi and Ekin for your contributions and thanks very much to Claudia and her team for putting together an excellent meeting (and for inviting us even though we don’t work on insects!). Some fascinating discussion of seminal fluid-mediated effects and various other reproductive phenomena in Drosophila, beetles, snails and flatworms, and a really friendly and open atmosphere (despite all the talk of Brexit in the coffee breaks!).

And finally, my aim of blogging about papers as we publish them has slipped a bit, so to catch up, I’m delighted to report that an experimental evolution study in Macrostomum lignano led by Tim Janicke has just come out in Journal of Evolutionary Biology, plus two review articles. The first is a chapter I wrote together with Lukas Schärer on sex in hermaphrodites for the Encyclopedia of Evolutionary Biology, and the second is my take on why flatworms are an interesting model group for studying various aspects of sexual diversity, commissioned for a forthcoming special issue of Molecular Reproduction & Development dedicated to Hermaphrodites.

Janicke T, Sandner P, Ramm SA, Vizoso DB, Schärer L (2016)
Experimentally evolved and phenotypically plastic responses to 
enforced monogamy in a hermaphroditic flatworm
Journal of Evolutionary Biology.

Schärer L, Ramm SA (2016) 
The Encyclopedia of Evolutionary Biology. Vol 2, p. 212-224.

Ramm SA (2016)
Exploring the sexual diversity of flatworms: Ecology, evolution,
and the molecular biology of reproduction.
Molecular Reproduction and Development.


Photo: our field site in Paleokastro, central Greece.


Huge congratulations to Yumi Nakadera, just awarded a Humboldt Research Fellowship to study the adaptive dynamics of seminal fluid in snails. The project will allow Yumi to continue developing her independent research programme over the next two years; it will be hosted in my lab here in Bielefeld, with collaboration partners in Amsterdam and Rennes.

Photo: the great pond snail, Lymnaea stagnalis (Public domain, via Wikipedia).


This year’s edition of Advances in the Study of Behavior will be published shortly, to which Paula Stockley and I have contributed an in-depth review of male adaptations to sperm competition in rodents. The review pulls together many of the different research strands we have ourselves been working on over the past several years, covering aspects such as copulatory behaviour, sperm production, sperm allocation, sperm quality, seminal fluid and genitalia, as well as the wider context of sperm competition studies by considering topics such as cryptic female choice, sexual conflict and multivariate selection and trade-offs. We argue that allied to traditional behavioural and morphological studies, recent molecular and genome-based approaches are transforming our understanding of traits that contribute to male competitive fertilization ability, closing the gap between genotypic and phenotypic perspectives on their adaptive evolution.

Hopefully the review will be a useful synthesis of where we’ve got to with respect to understanding sperm competition in this important vertebrate model group, and can serve as a guide to where we need to go next. The advance online version can be found here.

Integrating perspectives on rodent sperm competition.
Ramm SA, Stockley P (2016)
Advances in the Study of Behavior 48, in press. 
DOI: 10.1016/bs.asb.2016.02.003

Photo credit: Joad Hughes, via Unsplash.

Our latest experimental results in Macrostomum lignano flatworms demonstrate that individuals are able to produce sperm faster under conditions of higher sperm competition, presumably contributing to stronger sperm competitiveness. The findings are important because they imply that the speed of spermatogenesis is not a fixed property of a species or a genotype, but rather a malleable parameter that varies according to the prevailing environmental conditions. Whether or not other animals are capable of modulating the speed of spermatogenesis in this manner is currently unknown, but it could be that speeding up and slowing down spermatogenesis based on sperm competition cues is a taxonomically widespread – but until now largely overlooked – mechanism underlying phenotypic plasticity in sperm production.

The paper is based on experiments conducted by Athina Giannakara for her Master Thesis with me here in Bielefeld,  in collaboration with Lukas Schärer in Basel, and has just been published in BMC Evolutionary Biology.

Sperm competition-induced plasticity in the speed of spermatogenesis.
Giannakara A, Schärer L, Ramm SA (2016)
BMC Evolutionary Biology 16: 60. doi: 10.1186/s12862-016-0629-9

Picture: Detail from Fig. 1 in Giannakara et al. (2016).