Today my latest paper Schistocephalus parasite infection alters sticklebacks’ movement ability and thereby shapes social interactionshas been published in Scientific Reports! Although many fundamental aspects of host-parasite relationships have been unravelled, few studies have systematically investigated how parasites affect organismal movement. In this study we combine behavioural experiments of Schistocephalus solidus infected sticklebacks with individual-based simulations to understand how parasitism affects individual movement ability and how this in turn influences social interaction patterns.
By detailed tracking of the movements of the fish, we found that infected fish swam slower, accelerated slower, turned more slowly, and tended to be more predictable in their movements than did non-infected fish. Importantly, the strength of these effects increased with increasing parasite load (% of body weight), with the behaviour of more heavily infected fish being more impaired.
When grouped, pairs of infected fish moved more slowly, were less cohesive, less aligned, and less coordinated than healthy pairs. Mixed pairs exhibited intermediate behaviours and were primarily led by the non-infected fish. These social patterns emerged naturally in model simulations of self-organised groups composed of individuals with different speeds and turning tendency, consistent with changes in mobility and manoeuvrability due to infection.
Together, our results demonstrate how infection with a complex life cycle parasite affects the movement ability of individuals and how this in turn shapes social interactions, providing important mechanistic insights into the effects of parasites on host movement dynamics. Download our open access paper here!
Today I gave a talk at the 2020 ASAB Summer meeting about my recent work about the effects of Schistocephalus parasite infection on individual and social behaviour (paper here). It was my first talk at a virtual meeting, which took a bit more time to prepare, but despite being completely virtual due to the covid-19 pandemic, the conference turned out really well. Many people “attended” my talk, which was followed by a live Q&A with the other speakers in my session. All other conferences I was planning to attend this year (at least 4) have been cancelled this year, so it was great to that this conference was made possible in the virtual realm at least!
After chairing one of the sessions at the ASAB Summer Conference in Konstanz today it was time to give a talk myself. I presented an exciting project that explores the role of Schistocephalus parasite infection on individual movement and social interactions. Using experiments and individual-based modelling we show mechanistically this fascinating parasite strongly impairs mobility, with large cascading effects for animal groups.
Today I visited Münster to give an invited departmental seminar at the Institute for Evolution & Biodiversity. It was great to see the nice stickleback labs of Jörn Scharsack and Joachim Kurz and the way in which they are able to experimentally parasitise the fish with Schistocephalus.
Really enjoyed meeting many other members of the department and the very enthusiastic students in the group. I am excited about the possibilities for future collaborations with Jörn to unravel the mechanistic underpinnings of parasite infection and its link to personality variation. Thanks again to Jörn and Nicolle for inviting me!
Recently I started a couple experiments related to parasite infection of Sticklebacks with Schistocephalus, a tapeworm with a fascinating life cycle that requires three separate host species. Our experiments focus on how the parasite affect the fish’s movements, its social interactions and positioning, collective behaviour, and survival in the context of predation.
Today, when moving fish around for experiments, I noticed one particularly bulged individual that, instead of a the smooth elongated body had the body shape of a brick! A clear sign of Schistocephalus infection. We put it down and measured its body weight, both before and after opening up its stomach cavity. What we found was not one, not two, not three, but four individual flatworms with a total weight of 55% of that of the fish! Incredibly how the fish could actually survive with such an immense parasite load.
Three-spined stickleback before and after removing four Schistocephalus worms