News

Francesca’s project on Illuminating range shifts through evolutionary FIASCO: contrasting FaIling And Successful ColOnizations in replicated wild populations has begun!

We are excited for the upcoming collaborations, novel insights and more snail adventures ahead! More information can be found on Francesca’s website: https://raffinifrancescalab.weebly.com/the-fiasco-project.html

Photo (side): FIASCO logo

Congratulations Dr Katherine Hearn for passing her viva with minor corrections! Her PhD thesis was on sex chromosome evolution and local adaptation in the intertidal snail Littorina saxatilis.

Photo (side): Shell-abratory cakes handmade by Roger for the occasion - check out the mark-recapture label!!

Jenny Larsson had her PhD graduation on 20 October, after the ceremonies were postponed due to the Covid-19 pandemic. Congratulations once again to Jenny and all the best wishes for her career!

Photo: Jenny Larsson (left) and Roger Butlin (right) in their academic gowns at the graduation ceremony

Many congratulations to Martin Eriksson, who has successfully defended his PhD "Modelling the evolution of species ranges", on 14 October with Kimberley Gilbert as Opponent. He was supervised by Marina Rafajlovic.

Photo: Marina Rafajlovic (left) and Martin Eriksson (right) after a successful PhD defence

Amin Ghane, our MSc student was presented with the Prof. Michael B. Collins Award for the Best MSc Thesis presentation in the Marine Environment and Resources (MER) and Erasmus Mundus Joint Masters Degree Programme 2020-2022. He presented his work on "Sex-associated genomic variation in two ecotypes of Littorina saxatilis on the Swedish west coast".

Congratulations Amin on this achievement!

Photo: Amin Ghane at the Prof. Michael B. Collins award presentation ceremony

Two new Littorina papers accepted:

Koch EL, Ravinet M, Westram AM, Johannesson K, Butlin RK. 2022. Genetic architecture of repeated phenotypic divergence in Littorina saxatilis. Evolution.

Hearn KE, Koch EL, Stankowski S, Butlin RK, Faria R, Johannesson K, Westram AM. 2022. Differing associations between sex determination and sex-linked inversions in two ecotypes of Littorina saxatilis, Evolution Letters.

Congratulations to Eva and Katie!

An exciting Postdoc position in Portugal, to study chromosomal rearrangements in Littorina, with Rui Faria (PI), Roger Butlin (co-PI) and an additional team of truly excellent researchers.

The deadline is 15 May 2022.

More information about the position (PDF, 487KB).

Our new Leverhulme Trust funded project on "The roles of chromosomal inversions in polymorphism, adaptation and speciation" started on 28 March.

The focus will be on ecotypes of Littorina fabalis in Sweden, Iberia and the UK.

Roger and new research assistant Scott Barlow went collecting at Cemaes Bay, North Wales, and were very happy to be joined by Meghan Wharton and John Grahame.

Photo: Scott and Meghan collecting as the tide starts to go out. Despite the sunshine, there was a cold wind off the sea!

Samuel has made Littorina more famous by answering interview questions for this quirky article: Watching snail sex could help scientists see evolution in real-time

New paper by Samuel Perini and collaborators published in Journal of Molluscan studies.

Title: Very short mountings are enough for sperm transfer in Littorina saxatilis

Link: https://doi.org/10.1093/mollus/eyab049

Summary: Conflict over reproduction between females and males exists because of anisogamy and promiscuity. Together they generate differences in fitness optima between the sexes and result in antagonistic coevolution of female and male reproductive traits. Mounting duration is likely to be a compromise between male and female interests whose outcome depends on the intensity of sexual selection. 

The timing of sperm transfer during mounting is critical. For example, mountings may be interrupted before sperm is transferred as a consequence of female or male choice, or they may be prolonged to function as mate guarding. 

In the highly promiscuous intertidal snail Littorina saxatilis, mountings vary substantially in duration, from less than a minute to more than an hour, and it has been assumed that mountings of a few minutes do not result in any sperm being transferred. 

Here, we examined the timing of sperm transfer, a reproductive trait that is likely affected by sexual conflict. We performed time-controlled mounting trials using L. saxatilis males and virgin females, aiming to examine indirectly when the transfer of sperm starts. 

We observed the relationship between mounting duration and the proportion of developing embryos out of all eggs and embryos in the brood pouch. Developing embryos were observed in similar proportions in all treatments (ie 1, 5 and 10 or more minutes at which mountings were artificially interrupted), suggesting that sperm transfer begins rapidly (within 1 min) in L. saxatilis and very short matings do not result in sperm shortage in the females. 

We discuss how the observed pattern can be influenced by predation risk, population density, and female status and receptivity.

Many congratulations to Dr Jenny Larsson!

Jenny's PhD thesis "Understanding the evolution of shell shape in snails" has just been approved.

New paper by Eva Koch and collaborators published in Evolution Letters.

Title: Genetic variation for adaptive traits is associated with polymorphic inversions in Littorina saxatilis

Link: https://doi.org/10.1002/evl3.227

Summary: Chromosomal inversion polymorphisms, segments of chromosomes that are flipped in orientation and occur in reversed order in some individuals, have long been recognised to play an important role in local adaptation. They can reduce recombination in heterozygous individuals and, thus, help to maintain sets of locally adapted alleles. 

In a wide range of organisms, populations adapted to different habitats differ in frequency of inversion arrangements. However, getting a full understanding of the importance of inversions for adaptation requires confirmation of their influence on traits under divergent selection. 

Here, we studied a marine snail, L. saxatilis, that has evolved ecotypes adapted to wave exposure or crab predation. These two types occur in close proximity on different parts of the shore. Gene flow between them exists in contact zones. However, they exhibit strong phenotypic divergence in several traits under habitat-specific selection including size, shape, and behaviour. 

We used crosses between these ecotypes to identify genomic regions that explain variation in these traits. We could show that previously detected inversion regions contribute to adaptive divergence. Some inversions influenced multiple traits suggesting that they contain sets of locally adaptive alleles. 

Our study also identified regions without known inversions that are important for phenotypic divergence. Thus, we provide a more complete overview of the importance of inversions in relation to the remaining genome.

We are looking for a postdoc to work with us at Nord University, Norway. Find out more: https://www.jobbnorge.no/en/available-jobs/job/202881/researcher-position-2-years-in-evolutionary-biology-adaptation-genomics

Many congratulations to Jenny Larsson, who has defended her PhD thesis on Understanding the evolution of shell shape in snails on 31 March 2021.

The opponent was Professor Chris Klingenberg, from the University of Manchester and the internal examiner was Dr Chris Cooney, from the University of Sheffield.

Many congratulations to Samuel Perini, who has completed his PhD thesis on Reproductive Isolation at Contact Zones on 26 February 2021.

The opponent was Professor Anna Qvarnström, from the Department of Ecology and Genetics at Uppsala University.

Many congratulations to Samuel Perini, who has submitted his PhD thesis on Reproductive Isolation at Contact Zones.

His work covers a wide range of topics, including hybrid zones, sexual selection and phenotypic plasticity. Samuel's defence will happen online on 26 February – if you would like to join the event, register here.

Rui Faria, Sean Stankowski and Kerstin Johannesson have guest-edited a Special Issue on Speciation in Marine Environments in the Journal of Evolutionary Biology, which also features Littorina!

Francesca Raffini is currently guest-editing a SI on biological endemism – abstracts for contributions can still be submitted until June 2021.

Read an article about our new project in Norway, funded by the Research Council of Norway.

On this site, both researchers and the general public will find (hopefully) interesting information on our research, our team, evolution, genomics, and snails! We hope you enjoy your visit.