Congratulations to Sergio Ávila who was awarded with his doctoral degree today. Sergio conducted his PhD studies at the Institute for Evolution and Biodiversity supervised by Dr Claudia Fricke and Dr Sophie Armitage. In his PhD, Sergio investigated the link between mating and immunity in Drosophila melanogaster. We wish Sergio all the best for his future career!

Background

Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biocontrol. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts.

Results
We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp), highly syntenic, and the most AT-rich reported thus far for any arthropod (GC content: 25.8% and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We also find that absence of some immune genes (Toll and Imd pathways) resembles similar losses in their aphid hosts, highlighting the potential impact of symbiosis on both aphids and their parasitoids.


Conclusions
These findings are of fundamental interest for insect evolution and beyond. This will provide a strong foundation for further functional studies including coevolution with respect to their hosts, the basis of successful infection, and biocontrol. Both genomes are available at https://bipaa.genouest.org.


For the full paper, please click here.

Dennis, A.B., Ballesteros, G.I., Robin, S. et al. Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum. BMC Genomics 21, 376 (2020).

The vast majority of eukaryotes reproduces sexually, yet, the evolution and maintenance of sexual reproduction remains a puzzle in evolutionary biology. Reproducing sexually comes with high costs: Each sexually reproducing organism can only produce half as many offspring as an asexually reproducing organism (since only the females bear offspring and they usually make up only 50% of the population). In addition, finding a mate requires energy and may increase predation risk. To balance these costs, sexual reproduction must have benefits. One such benefit may be genetic diversity generated by reshuffling of maternal and paternal alleles. However, many organisms perform self-fertilization, meaning they undergo sexual reproduction without a partner involved and thus without generating new genetic variation. Another, so far rather neglected hypothesis is that the molecular mechanisms underlying sexual reproduction overlap with those of the cellular stress-response thereby providing a direct fitness advantage to the individual when engaging in sexual reproduction under stressful conditions. Together with colleagues from the National Research Council in Naples, Italy,  MGSE PI Francesco Catania and EvoPAD PhD student Valerio Vitali tested this hypothesis in the ciliate Paramecium tetraurelia and published the results in the May issue of Genome Biology and Evolution, which also contains a Highlight profile of their manuscript. Their results show that self-fertilizing Paramecium cells are much more likely to survive after a heat-shock compared to genetically identical cells that divide asexually. Results from transcriptional data suggest that heat-shock proteins may play a role in meiosis/fertilization and the response to environmental stress at the same time. They also reveal connections between metabolism and developmental program, which are reminiscent of observations in multicellular organisms. These results indicate that sexually reproducing organisms may gain direct fitness benefits through an overlap in the molecular processes involved in sexual reproduction and stress response thereby contributing to the prevalence of sex.

The article has been featured on various science news platforms such as EurekAlert!, Phys.org, The Medical News, Technology Networks, and Quanta Magazine. Additionally, it will be featured in the German Science Podcast ‘Undoder zum Quadrat’.

Original article: Thind AS*, Vitali V*, Guarracino MR, Catania F (2020) What's genetic variation got to do with it? Starvation-induced self-fertilization enhances survival in Paramecium. Genome Biol Evol 12:626-638. 10.1093/gbe/evaa052 [doi] *equally contributing authors

Highlight profile: McGrath C (2020) Highlight: Sex As Stress Management in Microbes. Genome Biol Evol 12:639-640. 10.1093/gbe/evaa080 [doi]

The WWU is one out of 10 universities to receive the "Eine Uni - ein Buch (one university - one book)" award by the Stifterverband für die Deutsche Wissenschaft for a project based on Prof Norbert Sachser's recent book "Der Mensch im Tier (The human animal)". The award includes a prize money of 10,000 EUR that will be used to organize a series of public events in the upcoming winter semester, also involving the MGSE. A lecture series, discussion forum and art, poetry and science slam aim to spark and promote a broad discussion both at WWU and within the local public, centering around the insights described in Nobert Sachser's book and their consequences for animal welfare and how we as humans view animals. The application for the award was filed by MGSE graduates Dr Niklas Kästner and Dr Tobias Zimmermann from the Department of Behavioural Biology. 

Link to WWU press release (in German)
Link to press release by the Stifterverband für die Deutsche Wissenschaft (in German)
Link to the application video on YouTube

MGSE PI Dr Francesco Catania is featured in a recent article discussing new insights into the evolution of sexual reproduction in Quanta magazine. Quanta magazine is an online publication aiming to enhance public understanding of science by reporting developments in mathematics, theoretical physics, theoretical computer science and the basic life sciences in an accessible manner to a broad audience. In the article, Francesco and others argue that while sexual reproduction usually carries costs to individuals and is thought to mainly benefit future generations through increasing genetic diversity, it may also directly benefit the individual engaging in sexual reproduction - especially in stressful environments. The basis for the article is a recent study headed by Francesco and EvoPAD PhD student Valerio Vitali published in Genome Biology and Evolution showing that self-fertilization can enhance stress resistance to starvation in the ciliate Paramecium tetraurelia.

Quanta magazine article: Why Sex? Biologists Find New Explanations, 23 April 2020

Original article: Thind AS*, Vitali V*, Guarracino MR, Catania F (2020) What’s genetic variation got to do with it? Starvation-induced self-fertilization enhances survival in Paramecium. Genome Biology and Evolution evaa052 doi: 10.1093/gbe/evaa052

MGSE graduates Niklas Kästner and Tobias Zimmermann founded an online magazine on animal behaviour, emotion, and cognition. On their website ETHOlogisch they publish articles to inform a broad audience about the current developments and level of knowledge in animal behaviour in an easy-to-understand and entertaining, while scientifically sound manner. The magazine is targeted towards a German-speaking audience.

Dr Niklas Kästner and Dr Tobias Zimmermann completed their PhDs in the Department of Behavioural Biology at the University of Münster and participated in the MGSE’s structured doctoral programme in course of their PhD studies.

On 13 and 14 February 2020, the MGSE hosted a workshop on "The Evolution of Social Immunity" with ETT fellow Barbara Milutinovic. The workshop started on Thursday with three keynote talks by invited speakers Peter Biedermann (University of Würzburg), Dino McMahon (Freie Universität Berlin), and Chris Pull (Royal Holloway University London, UK). On Friday morning, the participants discussed the concepts of social immunity and superorganisms.

On 5 February 2020, the MGSE hosted a workshop on "The Evolution of Reproductive Traits" with ETT fellow Geoff Findlay. Geoff opened the workshop with a talk on the role of de novo genes in male reproduction in Drosophila. Clelia Gasparini (University of Padova, Italy) and Steve Ramm (Bielefeld University) joined the workshop for keynote talks on postmating sexual selection in guppies and zebra fish and sex allocation and sexual conflict in hermaphroditic flatworms. In the afternoon, the students drafted research questions and a short proposal how to answer these and discussed them with the speakers.